Ask Ted!
If you have any questions you want answered, feel free to drop me a note. If you’ve got a question, chances are, there are lots of others out there with the same question. So ask away!
Comments
If you have any questions you want answered, feel free to drop me a note. If you’ve got a question, chances are, there are lots of others out there with the same question. So ask away!
Hey Ted,
Can you talk about the pros and cons of different insulation materials?
Hi Ted
Hope your well. Thanks for including me on your e-mail list. I like your blog and could of used it years ago.
On my 16 seer heat pump I can’t stand the fan revving up and down constantly. If I knew this I would of never got a 2 stage variable speed unit. It’s loud enough to wake you up at night. Starts at high, slows down for 30 seconds then high again. Was told it may be the thermostat and may have to upgrade. They say it is all about comfort but really feel it is defective. They said if I upgrade to $500 thermostat it may help?
Thanks
Steve
Thanks Steve,
That sounds defective to me. These systems typically ramp up slowly so that they’re unobtrusive. Not to say that they’re silent, but they should be much “smoother” sounding than a conventional single speed unit.
The ramping cycle is handled by the controller electronics in the unit, so that should be independent of the thermostat. However, it is possible that the thermostat is doing something odd with the multiple stages. Normally, they’ll turn on stage one, let it run a bit and then if it can’t satisfy the call for heat, it will ramp up to stage 2. If that doesn’t work, it will turn on the auxiliary heat strips. But this should all be very smooth.
One thing that could be making it run less than optimally is if you program your thermostat to use setbacks of more than a couple degrees. Heat pumps like to be run at a constant temperature with only changes of one or two degrees. If you have it programmed to, for example, set the temperature to 65 during the day when you’re not home, then up to 70 for bedtime, then it will most likely force it to high speed or auxiliary heat, making it run inefficiently.
You could also have an issue with how the refrigerant lines run through the wall. I have this problem – my lines are strapped to the wall outside my bedroom so that when the system comes on, there’s a loud buzzing as the vibrations are transmitted right into the wall. Very annoying.
One question – is the noise coming from the outside unit or the air handler?
[...] Ask Ted! [...]
Ted, I have oil fired forced hot water heat and indirect domestic hot water. In the basement and on the first floor I also have two chest freezers, a refrigerator/freezer, a dehumidifier, and two window air conditioners. Although I currently get domestic water from a main in the street, I also have two dug wells piped into the cellar (i.e. a lot of cool water) and a good site for solar thermal panels (i.e. a source of hot water). It seems to me that with a little plumbing there ought to be a clever way to make all the things that are hot but trying to be cold and all the things that are cold but trying to be hot work together to reduce my energy bill. My first thought was pipe cool water to the radiators of the freezers and dehumidifier, but would cooling their radiators make the compressors any more efficiently? My second thought was why not a sterling engine to generate electricity and preheat the domestic hot water. The WhisperGen system burns natural gas, and low hot-end temperatures are said to increase the size of a sterling engine, but in my cellar space isn’t an issue. Thoughts? Too bad you don’t live closer, we could tinker.
Ah tinkering. That would be fun!
You’ve got a lot going on there and your thoughts about using systems together instead of opposing one another makes a lot of sense. I’ve always wondered about utilizing waste heat from refrigerators to pre-heat water, for example. You’d have to be a bit clever about it to optimize the operation. For example, turn on the compressor to pre-heat the water at the same time as you’re taking a shower so that cold water is coming through the heat exchanger. Otherwise, you’d actually be less efficient than normal because it would be trying to extract heat into hot water. So there are definitely some nuances that would have to be considered.
The Stirling engine idea is always intriguing. My issue is that, for residential applications, the “waste heat” issue is much lower than in industrial apps where it’s a huge problem. Because of that, the benefit of reclaiming the waste heat in residences is reduced. I would probably just go solar-thermal since that’s well developed and highly efficient. Anything with off-the-shelf parts is going to make your life easier in the long run.
Have you looked into the wastewater heat recovery systems? I would have installed one of these but my drain line isn’t far enough below the bathroom and you really need the drain to be going out down low in the house. http://www.energysavers.gov/your_home/water_heating/index.cfm/mytopic=13040
Isn’t cellulose flammable? I know of at least one instance where the fireproofing compound on cellulose was washed away because of water damage and an electrical fire started from wires damaged by the same water damage. What about fiber metal insulation, I saw it on How It’s Made?
I’ll have to look into the cellulose flammability issue. I do know the green building community has wholeheartedly adopted it for many projects so perhaps it was a shortcoming of an older version of the fireproofing. Much cellulose is installed using a “damp spray” method these days, so I can’t imagine that the borates would come off however it’s manufactured today.
The last research report I saw showed that the house have a vastly improved fireproofing capacity, but much of that was because the fire couldn’t more through wall cavities, since it typically travels along air currents and it would just snuff out in the cellulose. However, if exposed to enough heat, they say it will burn. It has fire retardant properties, not fire proof.
Check into Roxsul- discovered it when our cabin was done 3 years ago and the stuff is incredible. For our home to be done in roxsul, it was only a 25% increase in insulation cost, but the non-flamability and r-value together were the drving factor. Around here, many of the trades use it for fireproofing at required spaces. Additionally, the wood stove and chimmney penetrations can be insulated right to the object- no need for the air space as with fiberglass or other insulations. Just cant put tight to can lights or other devices that air space to dispurse heat. Hope this helps…
Roxul is great stuff! Most of the Green builders I know love it as a replacement for fiberglass. It can be hard to get, but if you’re persistent, you can usually find a supplier to special order it for you.
I had a home energy audit 2 years ago and among the many things done as a result wad dense packing of cathedral ceiling with cellulose. I have no soffit vents. I have been talking to roofing contractors who all seem to be of the opinion that I need to add soffit ventilation. I have a ridge vent when my previous roof was applied approx, 17 years ago. I live near Albany, NY.
I read your article entitled “Cathedral Ceilings – Problems and Solutions where you state “I have no problem with ridge vents IF they’re implemented along with a proper amount of soffit vents. I have huge problems with ridge vents when installed without soffit vents.”
As I am going to have a new roof installed, this is the time for me to handle the cathedral ceiling properly.
What do you suggest?
If you had the roof dense packed, then adding soffit vents isn’t going to do anything for you. A dense-packed ceiling is supposed to be sealed because the cellulose dense packed should be stopping air movement.
However, you have to be really careful. It depends on the interior construction of your ceiling also.
When you say you’re having a new roof installed, are you actually removing all the roof sheathing? Are you having moisture or issues with your roof making it need a new roof? This is definitely the time to handle it “properly”.
Thanks for the reply! I’ve had problems with ice dams in the past and again this year (which was an especially bad year in our area (Albany, NY). I probably will have to replace some roof sheathing. The underside of the ceiling (sheetrock) has peeling paint and you can see dark spots where the rafters are. However, this problem existed prior to the dense packing. The gentleman who performed the home energy audit suggested the possibility of installing 3″ of polyiscyanurate to the underside of the ceiling for additional insulation properties which I would then cover with some kind of wooden ceiling. Should the ridge vent be closed or is that even possible? At this time I will consider any solutions you may offer. Thanks for your time and help!!
Bruce – Definitely problems! Did your auditor find signs of heat leakage from the house where the the ice damming occurred? Did you happen to notice the snow melt pattern on the roof? I have some posts with pictures of exactly this that you can check out. There’s an article on ice dams as well with a pointer to a Building Science article that goes over this in gruesome detail.
I like the idea of a few inches of polyiso on the inside and then using a nice facade inside that. I’ve recommended that before (in fact I want to do it to my house but my better half won’t let me…).
But before I did anything drastic (and potentially expensive), I would want to know why it is happening in the first place. There’s got to be some major heat leaks, maybe up through the wall and into the soffit area. If that’s the case, then even the polyiso treatment wouldn’t work.
If you can get your auditor out with their thermal camera, I would try scanning the roof from the outside on the coldest morning possible (hard this time of year) before the sun rises. That should show any hot spots on the roof which can give more clues as to the sources of the problems.
The other thing you can do, though it’s destructive, is to cut out the sheetrock in those areas where it’s damaged already and examine the roof sheathing and the construction in that area. That can be invaluable in tracking down these issues. I wouldn’t be surprised to find that the dense packing wasn’t done properly and perhaps left areas un-insulated.
Have you heard of Hunter Cool-Vent panels? They are made of polyisocyanate rigid foam with built-in venting. Foam, then 1″ cube wooden spacers about 1′ apart, attached to 3/4″ flakeboard, onto which your roofing material is attached. It was recommended for my vaulted, plank & beam ceilings, and is the cat’s meow. It replaced 1″ of old fashioned beaver board. Needless to say, I went from having icicles as big as my arm and the front door being frozen shut, to icicles only sometimes as big as my little pinkie. Big energy savings!
Thanks,I’ll have to look into those. I haven’t seen them but they sound like a great idea.
My insulation contractor Ned Reynolds of Newport, RI, is bullish on packed cellulose and says he’s be installing if for years with never a call-back. My contractor interrogated him for about an hour about vents and condensation. Ned said these days, with AC, the condensation is as likely to come in from the outside as the traditional route from the inside out and having cellulose with no vapor barrier allows the whole wall (or roof) to breathe, even without vents. The final factor in deciding was when we talked about mice. Mine is an 1850 farm house with a dry-laid stone foundation and hybrid framing (mix of post and beam and balloon frame) and it is very mousy. According to everyone we talked to, and my own experience, mice LOVE fiberglass insulation and HATE packed cellulose. Apparently the borate is an irritant to the mice and you can guarantee mice will stay out of walls/roofs that are stuffed with it. My finished attic has blown in cellulose and my cathedral ceiling-ed sunroom has 3″ of closed cell spray-in foam against the underside of the sheathing and then cellulose in the rest of the space and there’s narry a soffit vent or ridge vent in any of it. Fingers crossed it was the right decision.
I did my own cathedral ceiling this way as well. The Building Science article warns that many roofs are vapor impermeable to the top which can lead to problems. Between tar-paper, rubber membranes and whatever else is under the shingles, they note that the moisture can in fact migrate up to the underside of the roof sheathing and get trapped there. So I’m being a bit more conservative in my recommendations on dense packing cathedral ceilings. Doing what you did with 3″ closed cell spray foam would be great because the inner surface of the foam shouldn’t drop to a low enough temperature to allow condensation. So that’s safe. That construction dries to the inside. The only potential issue with that is when you have a roof leak, that saturates the roof sheathing and works its way down the topside of the foam. That would likely rot out your sheathing because it couldn’t dry out.
My preferred method for Bruce would be to pull off the rotten roof sheathing and check for any signs of moisture/rot. If there are, then you know there’s a problem. Unfortunately, my recommendation then would be to vacuum out all the cellulose and fill most of the cavity with foam to the back side of the ceiling – the part exposed when you pull the roof off. This will air/moisture seal the ceiling. I’d then leave a gap so that you could install soffit and ridge vents to allow ventilation under the roof deck which would both help any moisture in there dry out and keep the sheathing cold in the winter which will dramatically reduce the possibility of ice dams. If I were building a new house, I’d do it that way. Actually, I’d also add a couple inches of polyiso inside to reduce thermal bridging. I did the walls of my addition that way. Worked great! But I definitely take these things to the extreme…
Hi Ted:
When I have the rotten roof sheathing removed and a check reveals no moisture/rot, would you remove some of the cellulose to leave a 2″ gap for airflow and then have soffit vents installed. If the answer is to leave the cellulose as is; would you then close off the ridge vent?
Bruce – if you have rotten roof sheathing, it’s almost has to be due to interior moisture unless you had a bad roofing job and it’s been dripping for a long time.
An approach that I would consider is to create the air channel between the roof deck and the cellulose as you note. However, to avoid wind-washing the cellulose I would be inclined to use 2″ polyiso board foam pressed down into the cellulose and affixed in place with 1×2 nailers. It’s a little hard to describe.
_____________________ roof sheathing
| |I <– nailer I| | <—- rafters
| |==================| | 2" Poly-iso rigid board foam
| | ********************| | cellulose
| | ********************| |
| | ********************| |
——————————– interior sheet rock
Continued: On the other hand if rot/moisture is found then you are recommending the cellulose be removed and foam insulation be applied. Would that foam be closed as opposed to open and how many inches would you recommend?
Thanks again for your assistance!
It it were my house, that’s the approach I’d take – spray foam, closed cell.
I’d fill the cavity minus ~2″ to leave the air gap between the foam and the roof deck. Then use full soffit-ridge vent combination.
There may be some areas where you can’t get air flow due to obstructions (chimneys, etc.) With the closed cell foam filling the cavities, I wouldn’t worry about those areas. There’s not much you can do and if the foam job is done right, minimal moisture is getting through.
Let me know what you find when you start deconstruction. I’ll be very interested in seeing what happened. We can all learn from your misfortune!
Maybe take pictures and send them along. They’d be a great educational resource especially if you can trace the path of the moisture.
Hi, Ted-san,
Love your blog. I am looking into getting mini-splits for cooling in my home in Montgomery County PA and from some reading I’ve done I’m guessing the right system might also be used to replace our 37-year old boiler and hydronic heating system for heat as well. I appreciate any thoughts you have on the efficiency of these systems for heat. I also welcome any recommendations you might have for an HVAC outfit that installs either the Fujitsu or Mitsubishi systems since they seem to be the most efficient due to the variable speed/inverter technology.
Thanks,
Josh
Thanks Josh. You’re close by – I’m just in New Hope.
I use my mini-splits to supplement heating/cooling year round. I wouldn’t necessarily use it as my only system however, since the output drops as it gets cold. However, you might consider just getting some electric baseboards put in as supplemental backup which you’d only use when it gets too cold for the heat pumps. Electric baseboards are dirt cheap (less than $100 each) though the electrical work will of course drive up the cost.
As for efficiency (speaking for the Fujitsu Halcyon units I use), in our climate, they are at least equal my geothermal system and they’re better than any central system for air conditioning.
A lot depends on the size and layout of your home. With all these things, you want to start with a house that is well insulated and tight. This will help keep things more comfortable and efficient regardless of your heating system, but it’s especially important for heat pumps. Also, with the mini-splits, you really need one for each area. They’re great for us because it’s just my wife and I so we have one in our master bedroom and one in the living room. But if you had several used bedrooms, I’d want one for each bedroom. That really starts adding up!
If you do stick with a boiler, I’d strongly suggest looking into the Energy Kinetics System 2000. It’s less expensive than the high end one I got but more efficient overall due to a better design.
As for installers, for the Fujitsu units, I used TCS Heaing and Air Conditioning out of Philly. The owner lives in Bucks and they do a lot of work in Bucks and Montgomery County.
For the Energy Kinetics boiler, talk to Hannabery, based out of Quakertown. I believe they also do the Mitsubishi mini-split.
-Ted
Hi Ted,
How do you think the Fujitsu split units will work out in NM? We have radiant floor heat in the new house, but no cooling system at this time. I would like to keep the floor temp down a little in the winter and have some back up heat provided by a heat pump for the rooms we spend most of our time in, but don’t know if these units would work for us here due to the sometimes cold nights. Can the heat pump also be used to provide some hot water as well? I really don’t know much at all about these units, so look forward to your input.
Hope you are well,
Stephen
Hi Steve, thanks for asking!
The units should work quite well for supplemental heat even down to some of those chilly SF nights. It won’t blast out the heat at 5F, but it will still be much more efficient and throw off more heat than a typical space heater. And of course, the air conditioning will be welcome in the summer.
Because of the dry air out there, you’ll have less to worry about the heat pump frosting up as well.
No luck on the hot water though. There are some interesting units that will do hot water. See: the Daiken website for more info on these. I haven’t had any experience with them unfortunately, but they do sound like good tech. Note: I just checked their website and it looks like they’re for heating only because they’re all hydronic so that’s probably no good for you.
Well, Ted,
We had 2 Fujitsu tri-zone mini-split units installed in July, and they are great! Our house is very comfortable now, and our first utility bill was a very pleasant surprise. Thanks for the good advice!
Your brother Stephen in Santa Fe
Hey, that’s great news! That’s a great system with all those independent zones. Glad it’s working out for you.
Cheers,
-Ted
Hi Ted, You’ve written extensievly about heat pumps and particularly the Fujitsu. I happen to have the AOU24RML1+ARU12RML x2-Concealed Ceiling Heat Pump Dual-Zone Mini Split.
I mounted the units behind a wall and did a small dust into the room which hides them nicely. I love the performance, we mounted them upstair sin a loft room and they basically keep 3200 sq feet cool most of the time. My question is whether or not you can have them shut off like traditional HVAC units? Once I turn them on they run constantly and of course the inverter unit varies its speed greatly. I’d just like the to shut down at night sometime and can’t figure out if you can set them to do that. Thanks jim
Hmm, I’m not familiar with the specifics of those units but my units (12RLS) behave the same way. The blowers one them are very efficient and when I run on “auto” mode, they slow down to a whisper.
I do notice that the outdoor units do shut down even when the blowers are running and when I monitor their power draw, it drops down very low.
Otherwise, when I want it “off” I actually have to use the remote and turn the unit fully off.
-Ted
sorry for the typo’s on the previous post. That’s supposed be “a small duct” and “upstairs in a loft…”
Thanks Ted
That’s been my experience also although the blowers seem to have the same consistent output. The outdoor unit slows WAY down! These are the same units as yours except meant be roof or ceiling mounts. We adapted them for our particular utilization. I’ll check and see if the blowers are on auto mode and if they slow as well but overall these things work like a champ! I think they even use less or equivalent energy of an attic fan. Thanks again JIm
Interesting. My indoor unit has a number of setting – auto, low, medium, high, quiet. I usually run it on medium or high during the afternoon then switch it to auto for other times when demands are lower. At those times, the fan varies considerably on ours. Maybe the ceiling version behaves a bit differently?
Hi Ted,
Hope you’re enjoying your holiday weekend and you don’t answer this until Tuesday. Back to these minisplits again! I’m wondering about two things. The unit is locked when I try to set the thermostat at the remote as opposed to the unit. I’m concerned because the units sit in an attic space where it is hot so I’m not sure where the temperature is actually measured. I’d rather have it at the remote so I’m wondering if I can unlock this factory setting. I’m also having trouble getting the controllers to allow me to set the set back time and temperature. I also can’t get it to set in timer mode. In both functions I can get to the setting program but once I select a day, single day or all nothing else sets like time or temp. i keep going back to the instructions to see if I’m missing anything but no luck. Any ideas? thanks, jim
Hi Jim,
I’m always on my email. Don’t feel bad because I don’t have to put too much thought into this answer – “I don’t know!”
Seriously, I have no idea how that works. The only recommendation I have is to call the installer and see if they can help. Sorry I can’t be more helpful than that.
When you find an answer, let me know. I’m sure others will be interested in what you learn.
Cheers!
-Ted
Hi Ted,
We got a quote for minisplits and then, in light of the age of our boiler and the price of oil as well as the tax credit that runs until 2016, we’re considering upgrading our hydronic system to geothermal heat pump instead of getting the minisplits and then later replacing our old boiler. Do you have any thoughts about this and/or a favorite brand?
Josh,
The geothermal incentives are indeed attractive. The trick is, they’re not very friendly with conventional hydronic systems, unless you just have radiant underfloor heating.
Here’s the problem – I should probably write an article about this because it’s a common question…
Conventional boilers run at very high temperatures. By default, most are set up to run at 180F. When you run water that hot through radiators and baseboard fin-tube convectors, they throw off a lot of heat!
Geothermals are very efficient at making hot water at temperatures up to about 120-130F. Some can push this a little, but in general, physics stands in the way, so you’re very unlikely to get a geothermal thats producing hot water much above 130F with any reasonable efficiency.
So you have two things working against you. First, if you try to generate water hot enough for the radiators or baseboard convectors, you lose the efficiency. Second, if you run at a lower temperature where the geothermal is still somewhat efficient, the radiators won’t throw off enough heat to keep you warm.
If you have proper underfloor radiant (by proper, I mean tubes embedded in concrete and a tile floor), you can run at much lower temperatures, like 90F. At that temperature, geothermal is very efficient. So if you have that type of radiant of this sort, you can get very good results.
Feel free to ask if you have more questions!
-Ted
I should have been more clear- we’re running ductwork anyways, b/c getting enough cooling to all the rooms we need in our upstairs (6- 2 of which are rooms off of rooms off of the hallway) would require it anyways to work with our architecture and the minisplits. And we are also tired of the ups/downs of the oil market and trying to budget around that. If our boiler were newer, we would probably just do the minisplit upgrade for cooling but since it’s such a dinosaur (38 years old) we’re gonna scrap it.
Long term plan is to rip out the hydronic system as we renovate each room over the years.
Back to the geothermal: do you have a favorite brand and/or setup?
Thanks again,
Josh
Ah sorry. Well it was a useful discussion anyway!
For that, usually it turns out that your best luck is with the best installer in the area. Get someone really experienced who has done dozens or hundreds of installs and talk to references. Every Joe is jumping in the business because of the incentives so there are a lot of hacks out there.
Internally, most of the systems are very similar, so I wouldn’t worry about brand A vs. Brand B.
Hi Ted,
We have an expanded log cabin in Northern New Jersey with too many addition mistakes to mention, but we have an urgent one right now that I’d appreciate any input on:
We had our vaulted/cathedral tongue and groove original (about 60 years old) pine ceiling (which used to be “A” frame but we made a loft above, so now only half an A frame) re-roofed about 4 years ago. Unfortunately was not advised on insulation, (we had no GC for this addition, just a “project mgr” who wasn’t very knowledgeable in construction, as it turns out. Anyway, we know we are losing some heat out of there and now we have a leak but can’t pin point it. We were thinking of insulating on the inside with foam then sheetrock. We haven’t done anything because we didn’t know what to do about moisture issues, vapor barrier, etc., and it’s a good thing we didn’t because now we have a leak! We also have two skylights fit within log beams in that area that we put in 10 years ago. So, we don’t know how to go about re-roofing this area as far as insulation and correct roof system for this type of vaulted wood ceiling with skylights. We are getting ice cicles in that roof area but not sure if due to heat factor or need wider gutter due to pitch, etc. We believe the last roofer put a layer of ice shield, but who knows.
On another note, we have to replace our gas water heater soon which is in a low ceiling basement. Current water heater is 50 gallon and it really doesn’t have enough ventilation area due to low clearance, so we’ve been told. We have 2 CO readers and haven’t had a problem in 10 years here. We run out of water if two people take a shower at same time. Seems by looking online, that the lower profile tanks only come in electric or are only up to 40 gallons and since we are already running out of hot water at 50 gal, I’d hate to go to 40!. So we don’t know whether to try a tankless or what. Also we have hot water lobster in upstairs bathroom because takes for ever to get water warm up there (probably bad insulation below!) The lobster definitely helps but isn’t really compatible with tankless.
Any recommendations there?? I could go on and on, but will stop with those two pressing issues!
Thanks,
Mia
Hi Mia, Thanks for visiting. Sounds like some real issues going on there!
Leaks can be tricky to find because sometimes water will behave “strangely.” However, most of the time, it’s fairly predictable when there’s a large enough quantity that gravity is the main force on it. In general, it will run down hill, with a little side-to-side movement if it hits a barrier that redirects it. The tongue and groove ceiling, I’m assuming runs parallel with the roof’s width – i.e. not from ridge to soffit but from side-to-side. What can happen is that the water can run in the grooves and go sideways a bit. But, for the most, your water will leak into your house pretty much downhill from where the water leaks into the roof.
So the first question is – is the leak downhill from the skylights, maybe off to the side by a foot or two, but still pretty much downhill from the skylight?
If not, might the leak be somewhere downhill from a chimney?
Unless you have really bad shingles, the probability is vastly higher that the leak is occurring at the flashing for the skylight or chimney. With either of those, it should be relatively easy to fix for someone who knows what they’re doing.
So that should get you started troubleshooting the roof leak. You can also verify this problem using the high-tech testing called “the hose test.” Seriously, if you methodically spray the hose at your roof, you can pretty well pin down where the leak is. There’s definitely a technique to it, because it can take a real soaking and 5-10 minutes for the water to soak in and drip down to where it’s coming into the house. But the first thing I would do is a detailed visual inspection in the vicinity of the leak and up the slope, all the way to the peak.
Regarding your water heater – that lobster sounds interesting. I’ve never heard of it. But looking at the description, it’s probably doing the opposite of what they say. It’s not saving you energy because it’s constantly re-heating the water in the pipes every time they cool down. This is great for supplying instant hot water, but it’s bad for efficiency. The “chilli pepper” is a much better idea. You push a button and it circulates water in your pipes until it gets warm. So you still have to wait, but at least you’re not flushing tons of water down the drain. It’s the best compromise between a circulator and nothing.
With something like the Chili Pepper, you could use a tankless. Given your situation, that’s the route I’d go. You’ll just have to get a big capacity tankless system if you want to take two showers at once. Or, maybe consider using a lower flow shower head. You might have read my article on these…
Hope that helps. Post again with your leak troubleshooting findings.
-Ted
Thanks Ted, we’ll try those suggestions. Any suggestions for insulating materials for that problem area roof to prevent heat loss, assuming we are up to re-roofing? We did have someone come in with an IR camera a while back that said we were losing heat through the ceiling, but don’t know if it’s enough loss to warrant investing in ripping off shingles and insulating $$!
– Mia
It’s difficult to comment on insulation without knowing the ceiling construction. You noted that it’s tongue and groove. Is there anything above that or are the boards just nailed to the rafters? That would be the typical (incorrect) construction method. If you’re lucky, then they attached sheet rock to the rafters first, which acts as a good air barrier. So my answer will vary considerably depending upon that.
The big problem is, if they just attached the tongue & groove ceiling to the rafters, you can’t really properly insulate above it without ripping off the roof sheathing as well as shingles, and you really don’t want to go through that unless absolutely necessary!
If you don’t have moisture problems (other than the existing leak) then I wouldn’t mess with the roof insulation. But if there are signs that the roof sheathing has been moisture damaged and they are going to rip off the roof, then you have a once-in-a-lifetime opportunity to redo the roof “correctly.”
In the case that all the roof is going to be replaced, the best solution is to coordinate a spray foam insulator to come in right after the roofers rip off the sheathing. They can then spray the foam right in to the back side of the tongue and groove ceiling material. This will air and moisture seal it better than anything else. To keep costs down, you could do an inch of closed-cell foam and then have the rest of the space filled with damp applied cellulose, leaving 1″ of air space between the top of the cellulose and the roof sheathing. This is a ventilation channel allowing air to rise up through the soffit, go up the channels and out the ridge vent.
If you go this route, check out the excellent Cor-a-vent product for soffit and ridge venting. It’s the best I’ve seen (used it on my own house).
-Ted
ok, thanks again!
Mia
Hi Tted,
How noisy are the Fujitsu heat pumps? Are they like a hotel unit?
Thanks,
Bob
Mpls
Bob – they’re much better than most hotel units which I find to be very noisy. However, if you turn them on “high”, they’re moving a lot of air, so they definitely make a fair amount of fan noise. If you run it on any of the lower speeds (quiet, low, medium), they are very quiet indeed.
Cheers,
-Ted
hi Ted – i’ve read your comments regarding the Energy Kinetics system 2000 and i’m wondering if you might offer me some advice – i live in northern NJ in a 2700′ sq house that i bought in 2007 – the house has EK 2000 system with water tank (previous owner installed). I want to convert the house to natural gas from oil and have been told that i can convert the burner to a gas burner (without replacing the EK 2000 system which has been good to me)- i’ve also read that EK 2000 is really meant “for oil” – but in my situation since i already have the system in my house i want to avoid scrapping it and buying an entire new gas boiler. How easy is the conversion and how do i find a compnay with experience doing it ? all the EK 2000 dealers seem to be oil companies around NJ. How long is the job to convert and what would you estimate the cost for conversion parts? If you were in my situation would use also go for the conversion vs. an entire new system? is it ‘really true’ that the EK 2000 works just as well with NG compared to oil ? thanks in advance for you help !
Mike,
First, I’ll give you a disclaimer – I’m not an HVAC tech/installer, so I can’t give you any real-life numbers or comments based on experience with this type of conversion.
As I understand it, you should just be able to replace the burner with a natural gas burner that has been designed for oil to gas conversions. These type of conversion products, which should cost a few hundred dollars, should work fine because their designed for the purpose, and the flame they produce should be cleaner and less corrosive than an oil flame (which can produce sulfuric acid). So in theory, you shouldn’t have any problems.
Here’s a link to one such device: http://www.waynecombustion.com/news.aspx/oil-to-gas-conversion-burners
I suggest you call EK since they’re based in NJ. They should be able to give you a lead on someone in your area to do the conversion. However, if they don’t know, any competent gas HVAC tech should be able to swap out burners for you since they design these things to be “plug and play”
As for your other questions – I would absolutely go this route if I had NG in my area. The EK2000 is a fine unit, so I’d keep using it as long as possible.
Good luck! Let me know how it works out for you.
thanks for your quick reply and advice !
I am the author of the McGraw-Hill textbook “Retrofitting for Energy Conservation.” I have a free energy audit spreadsheet on my website at http://whclark.com as well as excerpts from the book. The book is now out of print, but McGraw-Hill has now transferred the copyright back to me. You can now order the book in a handy spiral bound form for a fraction of the original cost.
Thanks,
Bill Clark
Hi Bill,
Thanks for the contribution! I’ll check it out and hope it proves to be a valuable resource for my readers.
Cheers!
Hi Ted, I just found your blog and I’m really impressed with all the information. We are building a 2700 s/f house in Massachusetts and are now in the process of getting quotes from insulation contractors. We were planning to go with the “flash and batt” method with an inch of spray foam topped by fiberglass batts. So far, one estimator has said that’s “a fine method” and another says it’s not recommended in the northeast because over time, temperature fluctuations could lead to cracks in the relatively small thickness of foam. What do you think? We are using 2 x 6 construction.
Hi Barbara,
Thanks for writing. Hope I can be of help. My folks live in MA (in Falmouth/Woods Hole) and I spent quite a few years there myself. Beautiful area of the world…
On to your question – Flash & Batt: Even worse than cracks, if done improperly, it can lead to severe moisture/mold/rot issues. Here’s why – typically it’s done by spraying that thin layer of foam on the outer wall sheathing from the inside of the house, then packing the rest with inexpensive insulation. The best analogy I can make is imagine wearing a sweater with a rubber raincoat over it.
To continue the analogy, when you sweat, what happens? That moisture goes right through the sweater then comes to the rubber barrier. Before you know it, you’re dripping wet! This exact same thing happens with flash and batt. The fiberglass allows the moisture to flow through and the foam traps it.
Having said that, you can do flash and batt correctly in cold climates like MA. If the foam is sprayed to the back of the sheetrock and the fiberglass is packed outside the foam. Then what happens is the moisture from inside the house stops at the foam and never gets into the cold cavity of the walls or ceilings. Here the sweater and rain slicker analogy doesn’t work because the physics are different.
However, almost nobody does flash and batt like this because it means you have to install the sheetrock before the outer walls and roof sheathing.
Another way you can do F&B correctly is to use thicker foam on the outer walls. In your climate, you typically need at a minimum of 2″ (and likely more) foam if you’re going to use fiberglass with the foam. I’d have to go into the physics of dew points and moisture to fully explain this, but it’s well documented. The research of the best building scientists in North America supports this.
If I were you, rather than using 1″ of foam and the rest fiberglass, I’d go with 3+” of foam and forget the fiberglass. High density spray foam gives you R6.5 to R7 per inch, so with around 3″, you hit the requirements for building code and you don’t have to worry about condensation, mold and moisture like you would with F&B. And of course, the thicker foam the better, but you’re trying to get the best bang for your buck, so there’s going to be an optimal thickness for you based on what is cost effective vs. the R-value.
Ted,
I’m building a log home and want to plan a good roof. I would love exposed rafters on a cathedral ceiling, so a “built up” roof seems the way to go. How would you go about doing this if spray foam is too costly? Here’s my thought: rafters on a ridge pole, then I want to do plywood ceilings, so I would put 3/4″ plywood on the rafters. I would then spray foam fill everywhere plywood sheets meet. Then I would toenail 2×12′s ontop of the plywood. Use visqueen in all of the gaps I’ve created with the 2×12′s. Then fill the cavity with cellulose, but leave 1.5 inches for venting. build soffets on the overhang and install a ridge vent. This is in a high country arid climate, but it does rain and snow. Thanks!
Sounds like you’ve been doing your homework!
I’m not visualizing your proposed solution very well.
How about using one of the sheet-foam products like polyiso or blue-board? Use that for a couple layers, staggering the seams 50% between layers and taping seams. That can work really well to prevent air movement. Then you could use the cellulose for the rest of the cavity, with the air gap, giving you reasonably priced, high-R-value structure.
If you haven’t read through the roof material on the Building Science website, take a look there.They’ve got designs for a variety of climate zones and construction techniques.
Sounds logical to me! Thanks, Ted!
Ted, I’ve got serious condensation in my attic despite a humidistat/thermostat-controlled exhaust fan and gable vents. The cause might be air leakage through 15 hi-hats and other sources. I’m looking for knowledgeable contractors who can deal with this problem and would appreciate your suggestions.
Thanks very much.
Bill
Hey Bill,
You probably nailed it – those 15 high-hats are like open windows as far as moisture is concerned. If you’ve got insulation near them, and it appears discolored, then air has been moving through them.
There’s a good chance that it’s going through any access hatch/pull-down ladder as well.
I see you’re in the area – what town are you in? I might have a couple people who I could refer you to. You can email me directly: ted at soleburymountain . com
Ted…. I’d appreciate any leads you can provide to deal with the air leakage, ventilation (if necessary) and possibly insulation. I live in Malvern. Thank you!
Hi Ted
I recently had a pair of Daikin Quaternity mini split heat pumps installed. A 9k for the master bedroom and a 15k for open area entry/living/dinning/kitchen.
Extremely happy with my choice but wondering if a behaviour issue is common to all mini splits. I read your review on your Fujitsu RLS. Do yours or any of your followers have this same issue:
Both heating and cooling will move approx 5 degrees F passed the set point. e.g. I set my units to 65F to maintain a room temp of 70F as measured on my aux heating tstat and another I have for a propane f/p. At the same time the display on the Daikin remotes indicates that the sensor on the wall mounted (8 ft ceiling) indicates 72F. Both units behave the same.
I can understand the extra 2 degrees on the sensor, based on heighth but is the 5 degrees passed set point not a tad excessive?
Those look like excellent units. Actually, they look almost identical to the Fujitsu, so I wonder if they’re the same unit with different covers?
As for your set point issues – I do adjust mine based more on the stat near where I sit rather than the number on the unit. But in part, that’s because the units are mounted in somewhat strange locations, so that will confuse the issue.
For example, I had to mount my living room unit near the floor instead of high on the wall. So the unit is measuring the floor temperature rather than the ceiling temperature. With typical stratification of air, you might have a five degree temperature difference between these locations. Is seems like you’ve already thought of this. Five degrees does seem excessive.
In my experience, the temperatures are pretty accurate overall. In my bedroom, where the unit is mounted on the wall, the temperature setting and the wall thermostat match up within a degree or two.
So the quick answer is, 5 degrees seems excessive, assuming that you’re getting good air mixing in the room. Is this a problem? Not really, it’s just an arbitrary number. As long as the units keep the temperature consistent, I wouldn’t worry about what it thinks the temperature is.
thanks Ted.
you’re right about the similarities between RLS and Quaternity. RLS was my 2nd choice, I went with Daikin based on the Dehumidification capabilities. Being able to lower humidity without lowering temperature seemed a nice option for our region in Nova Scotia.
My installer tells me Daikin can change boards in my units to overcome the 5 degree diff.
He’s going ahead with that for another client and will get back to me based on those results.
thanks again, great blog.
Thanks for the info. Great to hear about the board. Hopefully that will get it all going just right for you.
BTW – the Fujitsu also has the dehudification mode. I use that in spring and fall.
Thanks for the feedback. Hope to hear more from you.
what outside temperature does not work on a 12,000 btu a/c heat pump. we live in montreal, qc.
tnx j.s.
Hi Jerry,
You’ll have to check with the manufacturer’s spec sheet on your unit. Every unit has an ‘output curve’ that defines how much heat it can deliver based on outside conditions. For example, there are some modern units that are designed for cold temperatures and can put out a good amount of heat even at 0F. On the other hand, some normal system drop down to about 50% output when you get to freezing temperatures.
Typically, when you’re about five to ten degrees below freezing to about five degrees above freezing, heat pumps struggle because of the need for defrost cycles. If you look at the outdoor unit at these temperatures, you’ll see a lot of ice forming on the coils. The unit has to run in reverse periodically to melt the ice. When it does, it actually puts cold air into the house and heats outside.
However, the overall efficiency of a heat pump, even at these conditions, will be higher than using a normal electric space heater. So even when it’s somewhat cold out, you’re best off using the heat pump and supplementing it with other heat as needed.
Check with the manufacturer to see what range of temperatures they recommend.
Hello Ted, you have answered a couple of my questions about the 12RLS and this week I had one installed. The first couple of days the temp was about 0 F but last nite it went down to about 10 F and has not warmed up much today and the Fujitsu is performaning well, I have an older home on three levels with variable degrees of insulation, all new windows. The unit is on the lowest level of three and is just outside my kitchen window and the indoor air handler is just a few feet away (6′) over the kitchen sink. Its keeping the house nice and warm but I am wondering what can I expect as the weather gets colder? I just noticed a little while ago that it went into defrost cycle for less than 10 min. and when it restarted the fan came on a what seemed a higher output than normal when set at”medium” I chkd the output air at the unit and it was about 94F with the remote set at 74F. Is that normal in you experience? I was disappointed with the manual that came with the unit. very little about how to operate it for peak performance, and nothing on what to expect with varing climate conditions.
Thanks for your help Ted
Jack Leonard
Ontario, Canada
Hey Jack,
Thanks so much for writing. Glad to hear that the Fujitsu is working well under such harsh conditions! I haven’t pushed my units that hard, so it’s great to hear from you.
The defrost cycles get “funky” – expect some strange sounds and fan operation during that time. I’ve found that my unit suddenly goes to defrost, the fan cuts out and then it works overtime when the cycle is done. So the behavior of your unit sounds “normal” from my experience.
The output air depends on a lot of factors, but typically, I get 100-110 degree air out during moderate temperatures outside. When it gets colder, the system has to work harder, so 94F sounds in the right ballpark.
My expectations these days for manuals are pretty low. I would have liked to see more also. Pretty much, I just set the units to “auto” and put the temperature around where I want it to be, and let it do it’s thing. You’ll definitely notice diminished output as it gets colder. With heat pumps, 50% decrease in overall heat output when the air drops to 10F is not unusual. These mini-splits with inverter drive compressors do better because they can push the compressor hard at cold temperatures but you’re still fighting physics. If you get appreciable hot air out when it’s under 10F, consider yourself lucky
I hope you’ll report back and share your experiences as the temperatures drop.
-Ted
Hello Ted, well since I last wrote to you just after having the 12RLS installed (Dec 14) we have had a wide range to temps here. All the way from -15C to +5C, sorry I’m going to give temps in celius that is what I’m used to and all my themomters are in C and thats how I’m recording temps. Anywat during this great variation in temps I have seen output temps in the 35C to 41C depending on the outside temps I guess? For instance on 18 Dec the outside air was -15C and the units output was 37C, on 21 Dec with an outside temp of -3C the output was 41C.
I keep the remote @ 74F and set on AUTO.
What I am most pleased about is that it is keeping the rooms I wanted to heat with the 12RLS at about 74F pretty constantly. Today for instance its really brutal ot there the temp is 12C and heading lower but the wind chill is already -22C and that is cold for 3 in the afternoon.
thats it for now
best regards and happy new year
Jack
Hi Jack, that is an excellent New Year’s message. I’m really happy to hear that these are working out for you so well. I’ll bet Fujitsu would be as well.
You’ve got it right – the maximum output temperature of the system will be directly related to the temperature. I’ll tell you, 37C output from a heat pump when the outdoor temperature was -15C is spectacular. From what I’ve seen in conventional heat pumps, you’re usually lucky to get 30C at those outdoor temperatures.
Thanks so much for the report. I’m sure others will be very interested in this.
-Ted
I can’t find a Fujitsu dealer in Northern Ohio. Did you have a local Fujitsu dealer or did you have to get them some other way? Thanks.
I had a local HVAC contractor supply them.
There should be someone in your area qualified to install them.
Try calling Fujitsu and asking for an installer near you.
Hello Ted, another report from the “frozen” north. If you think you have enough info on my experience with the 12RLS let me know, I don’t want to get boring. I will try to give temps in both celcius and farenheit so as not to confuse anyone reading this. Canada changed to C back in the mid eighties and I have mostly mentally converted. The remote for the 12RLS is just in F as near as I can find out.
The morning of the 29th Dec here was quite cold -23.5C (10 below 0 F) but was clear with a calm wind. At 7:30 AM I ck’d the output of the 12RLS which was at 35C ( about 97F).
I usually keep the 12RLS set at 74F which seems to keep the area I want to heat at about 24C (about 74F) which seems to be comfortable most of the time.
At about 8:30 AM with the outside temp still at about -23C I upped the temp control on the 12RLS remote to 76F, within a few minutes the unit was putting air out at 39C (about 102F?) with a greatly increased fan speed.
The temp that day stayed around -18 to -19C (3 or 4 below 0F) and the output from the air handler maintained at about 35C with the remote set back to 74F.
My observation so far is that the heat pump does better on clear, dry days rather than on a day like today which is cloudy with snow flurries and high humidity.
Today while the temp is only -12 or 13C the heat output is still at about 35C.
Well Ted I hope you and your readers fine this info useful?
Jack
Jack, it’s always good to hear from you. I’m a data junkie so I never get tired of this. Plus, there’s nothing more valuable than actual field experience to help others who might be considering a similar setup.
The more you say about your experiences the more impressed I get. I’m alway very conservative recommending heat pump technology in cold climates like yours, but it really seems like the Fujitsu is working well.
Your observation about the type of weather matches up well with the theory and my own experiences. In more humid weather, the heat pump coils will freeze up more, requiring additional defrost cycles and lower overall heating effectiveness. With dry air, the system can crank away without the performance degradation.
Cheers,
-Ted
Thanks for the info Jack, I am really surprised to see the 12RLS performing that good in frigid Canadian conditions. It gives me confidence that a mini split heat pump would perform well here where the temperature rarely gets below 0F(-18C). I am in the process of looking for someone that will sell me a Fujitsu 12RLS. I would like to avoid some of the high installation costs and equipment markups by doing part of the instillation myself and letting the contractor make the line set connections, do the pressure test, and vacuum the system.
Due to Fujitsu’s strict “dealer sales only” policy it might not be possible for me to install any part of the system or even find an HVAC contractor the sells Fujitsu products in my area. Hopefully other manufacturers’ heat pumps will perform as well as the Fujitsu 12RLS, although the 12RLS has the best SEER (25) and best HSPF (12) of any mini-split I have looked into.
Check into the Daikin units as well. Check out this link. Maybe you could find someone to install one of those.
There are some sources on the web where you can buy the 12RLS for under $2000 and if you’ve got a cooperative HVAC contractor, you could do much of the work yourself. But as you noted, you’d be unlikely to get a warranty.
Mitsubishi has an extensive line of mini-splits though the performance specs aren’t as impressive. But they’re considered the workhorses in the industry. For heating, be sure to focus on the HSPF rating rather than the SEER. Though they typically go together, the HSPF’s may not vary as much as might be indicated by the SEER’s.
There are also some units that have a “turbo” mode for when it gets cold. You lose some efficiency, but that’s less important than heating capacity when you’re just trying to stay warm.
Ted: we bought a home that has 3″ rigid foam (owens pink) that was cut between old timbers and foamed tight to the exterior wall. The builders then built and insulated a 2×4 wall inside the old wall to provide a flat wall and add insulation value. This wall was insulated using r-15 Roxsul brand insulation, and a 6 mil vapor barrier before sheetrocking. When we cut into the wall to add an outlet for TV, there was moisture on the inside of the poly where it contacts the Roxsul- not much, and only on the south side. I asked the builder who did the work, and he said he didnt want the vb but code said it had to be there. They had to keep the historic exterior, so they couldn’t add rigid board to the outside. The building inspector indicated that he required the vapor barrier per code against the builders wishes…. now what do we do? What is right? Dubuque IA
When you say inside, do you mean facing the sheetrock or right against the roxul?
That sounds like a pretty tough situation. The rigid foam is slightly vapor permeable but clearly not compared to the vapor barrier! Most building science folks push for removing of those building codes that force the blind use of vapor barriers exactly for these reasons.
The strange thing is that the moisture is condensing near the inner wall. That’s a big concern because that’s a red flag for a LOT of moisture being trapped in the walls.
I’m assuming this was during the winter?
On the south side is also suspicious. Sometimes this happens when the sun “pushes” the moisture through the wall, especially with brick exteriors which can act like sponges for moisture. What is the exterior of this wall like?
The more information you can provide, the better.
So far, we have only found it on the roxsul side of the plastic, only on south side. The exterior is only limestone and concrete foundation, clapboard siding on bottom of framed walls, gingerbread above windows/gables. Exterior also has a double layer of aspalt felt, thicker than current 30lb. We found this putting in exterior outlets. Did a larger inspection hole inside, roxsul and pink are dry- less than 7-12% once past the outer boundry using moisture meter- so the moisture is definately at the poly and roxsul. Did 3/8″ drill holes in wall along the top of the stud cavities, where they would be covered by new crown, and some have moisture marks 2 days later. Builder did this wall when high humidity in summer, and no AC. AC was used after drywall was sanded before painting and floors- his thought is moisture is trapped in cavity from this summer period, and has migrated to the interior face. NEW inspector agrees with builder- no vapor barrier, only housewrap on interior if desired. Rafters and plate area are foamed with close cell up top; the house has 6″ polyiso board on top of old roof deck, and iso board cut between full 3×6 rafters. We did some test readings there and up on roof via ridge and other points- all were less than 10% moisture. So at least it’s limited to south wall!
My only thought now to solve is to drill holes at base and behind crown area to let wall breathe, otherwise we have a project in taking down drywall and removing the interior vapor barrier. Or put a whole lot of holes in wall with drill, then mud and repaint! Hope you might have some other points to ponder on this…
You question/situation is so interesting, I’m going to turn it into a full post. Stay tuned for the full report!
Ok – another article done!
Let’s continue the dialog in the comments of the new article.
I wanted to follow up with you to see if you saw my article addressing your moisture issues. I’d be very interested to learn what you discover as you do work on your walls. This could be a great learning experience for others and help them avoid similar issues in their own homes.
Here’s the end result: we pulled the drywall off, and the poly. Out came the roxsul just to chek for any other issues, such as leaks, etc. Nothing was found, and the roof is brand new, no water issues were seen on the foam or foam side of the wall, or near the roof plate. The moisture meter reading was less than 7% overall on the old timbers where they were probed. One interesting thing to note from the builder- the home was pressure washed by the lead abatement crew to remove any dust and residue from lead items (Dubuque area commonly used lead mine leftovers for mixing plaster, cement, etc.). Again, this was in the summer, and the builder began right after the crew left. We only found the moisture on poly right at the roxsul; nothing in the roxsul or past towards the foam. In fact, even with no wall/insulation/vapor barrier, the wall is warm to touch from the sun hitting the exterior (historic gunmetal grey paint- explains the heat that is absorbed)
We are letting the wall breathe out now, and next week we are reinstalling the roxsul and drywall, and NO vapor barrier. All the moisture seemed to be on the poly, where it couldn’t escape as it was sealed tight. As a note, no other walls in the old part of the house had this same issue. However,the other walls are getting holes drilled in the drywall and through the poly, just make sure they can breathe as well.
As the previous inspector order the wrong things to be done despite the objections of the builder, we are asking for a refund of a portion of the permit fee, which is about the most we can do in this case. Like you stated, drywall and paint are inexpensive! (plus, we can add the outlets we wanted, which is what led us to discover the issue in the first place! Bonus!) As a note the energy efficiency of the home- our furnace rarely runs- the wood stove heats the home, and the house is so well insulated that even with no fire going, it took over 36 hours for the interior temp to drop from 73 to 65 with outside temps of 20 to 40f. Someone forgot to turn the furnace on when we left for Christmas!
Thanks for the report. Very interesting and still perplexing! Please share if you learn anything else in the future.
Good luck!
Ted, here is something I wrote up about all the work I had done in 2006. It has a link to the Cool Vent panels.
After comparing the energy audit results and recommendations of three different contractors in 2006, I chose one of the companies to complete the majority of work that needed to be done to make my home more energy efficient. (Other contractors completed smaller jobs.) The main contractor initiated the paperwork necessary for me to receive not only a $6,000 Energy Star grant, but also a 4% low interest loan through NYSERDA. Here is a list of the work done:
1. Replaced original 1950’s era gas furnace with new high efficiency model
2. Replaced a nearly 20-year-old refrigerator with an Energy Star model
3. Replaced a 1970’s era (avocado anyone?) washer with Energy Star model
4. Replaced 4 ten+ year old low-quality vinyl windows with Energy Star windows (remainder of windows already replaced with triple-pane vinyl windows)
5. Replaced 6 single pane basement windows with glass block windows
6. Added AirKrete ® http://www.airkrete.com/ insulation in all exterior walls
7. Added foam insulation to all rim joists, and under house wing over garage
8. Replaced rear and side exterior doors (front door already replaced)
9. Finished installation of Hunter Cool-Vent TM panels on roof over vaulted ceilings http://www.hpanels.com/pages/cool-vent_articles.html
I now have a year’s worth of data on the resulting energy savings, from my local utility’s website showing my home’s energy use over the past two years. My gas usage in therms decreased by 25%. My electricity use in kWh decreased by 44%. Not too shabby, and I still have things to tweak!
……………………………………………………………………………….
My electric use over the past year (12/07-11/08) has been 3,383 KWH, which is 44% less than before all the work was done. 3,383 KWH times .095 rate for renewable/green electricity = $321.38 + RG&E delivery charges (varies). My gas use of the past year was 522 therms. That is 25% less than it was before the improvements. 522 therms times $1.305 per therm = $681.21 + RG&E delivery charges (varies). All totaled, my utility bills over the last year were about $1480.00. [This would be a lot easier to figure out without RG&E's separate delivery charges!]
Margie, thanks so much for sharing. Kudos on a successful energy-efficiency renovation!Your savings are impressive. It’s really meaningful to share ‘real-life’ information like this. I think a lot of people are skeptical and think that all these things are theoretical. Keep up the great work and keep spreading your successes.
By the way, it looks like they changed the link to the panels. Here’s a link to the page of products.
Ted,
You’re welcome! It is a personal mission of mine to encourage and teach about saving energy. Thanks for correcting the link.
The level of insulation in justice’s home is truly impressive! I can’t get any more in my walls – would have to reside the whole house and put foam panels on the outside. If my house could be jealous, it would be!
Ted,
First off, you have a great page not just in information, but in overall design. I have a question for you and haven’t been able to find a good answer yet. I live in a Upstate New York home built in the 30′s. The previous owner decided to add an attic bedroom, but they didn’t insulate correctly.
The attic has your basic knee walls, improperly insulated with exposed pink fiberglass on the unfinished side. That is going to be easy to fix. I cut away some of the floor on the finished side to see what was under it. They left kraft faced R-22 spanning the joists between floors (2x8s). It was clean so I’m guessing air movement is minimal. Would it be beneficial for me to remove some of the floor and properly block below the knee walls?
My goal is to make the room more comfortable and energy efficient. I would like to get a return on my investment, but may not live here much longer than another 5 years. Does the work sound worth while?
Thanks Chris, I appreciate the feedback!
Those attic rooms – ugh, everybody seems to do them wrong.
If you can get behind the kneewall to see the insulation, work from that side. Usually the cavities are open and easily accessible for air sealing. The quickest/easiest way is the “insulation pillow” – fill a kitchen sized garbage back with insulation and then pack that in the gap under the kneewall to form an air-tight plug.
On the back of the wall, I know some contractors who will use 2″ rigid board foam affixed to the knee wall studs. That insulates the studs to minimize the thermal bridging and holds in the fiberglass that’s in there so you double the benefit giving a knee wall R-value of about R-20. An alternative is to insulate below the rafters and not on the back of the kneewall. Depending on access, this may or may not work for you. See the link at the end of my reply for a diagram.
Doing these two should be a cost-effective weekend job if it’s a modest sized space.
If you can, you should also take a look up the sloped ceiling (from the attic side) and see what’s going on in there. Most homes of this vintage will either have this space packed with insulation or have nothing at all. If it already has insulation, and the roof shows no sign of moisture damage, don’t touch it. I don’t like messing with things that have been working for decades. If it doesn’t have insulation, this can be a tough retrofit. Without insulation, those sloped portions will bake in the summer and freeze in the winter. There’s some serious thought that has to go into that retrofit because done incorrectly, you can end up with a rotten roof.
I’d suggest taking a look at the following link for some ideas:
Thanks for the input. There is enough space behind the wall for me to crawl and repair. I actually did what you suggested with the rigid foam over the studs (in a small test area) a few months ago. There is a lot of conflicting information on the internet, and some of it indicated that I was just going to create a moisture problem between the XPS board and the faced insulation that is currently in the knee wall. So I stopped and decided to research more.
I was considering a 600 bd/ft spray foam kit. I was thinking about cutting out the fiberglass on the knee wall and using a combination rigid foam and spray. Does this make more sense? I liked this hybrid route because of the cost savings. If this does make sense, can I do a 2″ XPS board in the wall and then cover the rest of the space (and the 2x4s) with an inch of spray foam to air seal?
Back to the attic floor. The crawlspace has decking over the joist and I think it may be too small a space to comfortably work and cut away the decking. Would it be worth it to do that work or should I leave it and spray in cellulose on the deck floor after I am done addressing the knee wall? If a picture is worth 1,000 words; what would a YouTube video be? The video probably helps explain it a little better.
Hey, awesome! A video really does tell the story.
That’s a familiar looking knee wall/attic space. There’s probably millions out there just like that.
Regarding moisture – you do want to avoid the “double vapor barrier” trap, so faced insulation + board foam can be a problem. It’s not likely to be one, but for safety, it is best to use unfaced insulation or remove the facing from the fiberglass. Of course, then people will complain because the vapor retarder is supposed to be on the “warm side”, meaning facing the inside of the house. If you strip the facing and then use XPS, you’re effectively putting the vapor retarder on the cold side.
On your spray foam question – that approach would work quite well. If you’ve got a table saw, you can rip lots of XPS into strips to go between the studs then just spray over it to lock in the goodness. I’ve used quite a few of those foam kits and they’re a bit finicky. At the end of the day, I usually wish that I’d just called in a professional foam contractor to do the job! Small jobs like band joists are great, but this is a pretty extensive area. I’d say it’s on the border between DIY and call in the pros.
Personally, I prefer the approach of insulation under the roof for these types of attic spaces. While your setup is the most common, there are enough leak points that it can be a real pain to properly insulate everything. Insulating under the roof and bringing the attic into the conditioned space of the house can be much easier and more effective. I’ll try to write up a full article on this soon.
In a nutshell, here’s what I’d personally do:
1) ensure proper soffit venting and clear air pathway up to the top attic and its venting (you’ve got chutes there now, so I’m assuming this is a-ok but you should double check)
2) Install 1 1/2″ to 2″ spacer blocks under the roof sheathing to serve as an air gap from the soffit to the existing chutes
3) Install a couple layers of 2″ XPS in between the rafters, leaving an air gap from the soffit vent up above the insulation
4) Spray foam under the rafters and XPS to seal everything up air-tight. Or, just add another layer of XPS. Spray foam seals things up better, so I prefer that method.
See this link for some diagrams:
http://oikos.com/esb/51/sideattics.html
Hope that helps.
Thanks for the response. That was a helpful link. I like the idea of doing the entire roof deck. I’m not sure if it will be within budget. Using the roof deck/foam/spray method, I will have a difficult time meeting the R-49 requirement for my zone. I would be closer to R-25 with 4 inches or rigid foam and some spray. I’m guessing that combination may out preform R-49 fiberglass with air leaks.
I will probably cut out the sheetrock on the center of the roof, but I won’t be able to spray over the rigid foam between the sloped rafters (because the room is finished). Not being able to seal that portion of the roof will cause some air leakage. Is this still an acceptable method without being able to seal it up?
That little section from the top of the knee wall to the flat section of the top attic is always a problematic section because of existing finished ceilings.
The “safe” approach is to to provide continuous ventilation under the roof deck all the way up to the peak from the soffits. If you’re using rigid board foam with furring strips mounted to the rafters as spacers, you can re-pack insulation in those sloped areas and spray right from the top of the knee wall to the bottom side of the foam. That will also help the non-foam insulation in the sloped areas perform better because air won’t be moving through it.
Instead of XPS you could use polyiso board foam. The R-value can’t be beat at around R-7 per inch (there’s some controversy around the exact R-value). It’s more expensive than the XPS but if you want to squeeze out every bit of R-value, you can’t beat it.
One other thing to look at is the “whole-wall” R-value (actually, whole roof in this case). If you fill the cavity minus the air space with board foam then spray foam over that and cover the rafters with an inch or two of foam, you’re vastly improving the R-value of the rafters, which would otherwise drag down the total R-value in the normal situation because the rafters lead to thermal bridging. That’s what’s going on in the sloped section that you can’t do anything about. In the rest, as you note, you’re not going to hit R-49, but also as you note, I’d take R-30 of polyiso sealed with spray foam any day over R-49 of loose fill or batts installed normally. There’s some good charts here: http://www.monolithic.com/stories/r-value-fairy-tale-the-myth-of-insulation-values/photos
In particular, check out the R-value vs. temperature graph. Fiberglass loses substantial R-value with temperature – not a great characteristic for insulation!
Ted,
I am finally getting around to installing a roof-vented bathroom fan as the first step in decreasing winter moisture in my attic. Once that’s done, I’m going to get additional insulation blown into the attic (currently R19 bats of ~40 year vintage) as a precursor to replacing our 40 year old boiler/hydronic system with geothermal some time in the next 2 years. Our attic currently has flooring down the middle (was used for storage- I don’t store things in attics). Is it better to have loose fill piled on top of the plywood, remove the plywood, or have the area under the wood dense-packed?
Ok, this is an ideal time to check for other air leaks between your living space and attic. Do NOT blow in insulation before doing this or you’ll regret it. I nearly killed my insulation guy who thought he was doing me a favor when he blew about 16″ of cellulose on top my already insulated attic, making it very difficult for me to work up there! Trust me on this.
If you want to “do it right”, you’ll locate all the wire penetrations and electrical boxes and other hidden holes and you’ll seal them while it’s easy. Then you’ll re-insulate afterwards. Also, if you ever plan on running new wires, light fixtures, etc., do it before blowing insulation in there. It’s a real bugger to work in an attic full of loose fill.
As for the flooring, you really could go any route you mentioned. In my own attic, I kept a narrow walkway between my attic access, down the center of the attic and to my air handler. I stuck batts under the 18″ or so of walkway and then have the blown in stuff covering much of it. This way, when I do need to run wires or do work up there, I just sweep the loose fill out of the way and have a safe access across the attic rather than trying to balance on the joists.
Thanks again for your thoughtful reply. I should have specified that we’re insulating following foam plugging of air leaks and placement of vent chutes (we had 36 soffit vents added last summer and covered the gable vents so that the ridge vent might work right) – I checked with our Angie’s List- multiply-approved contractor to ensure this would be done. While we may be adding a forced air system at some point with the geothermal, I’m interested in getting the insulation advantage now and I’m sure HVAC guys are used to crawling around in attics full of the junk, right? One last thing: the access to the attic is up a stair/shelf in the closet with a ~4X8 sheet on hinges as the door/hatch. Any good suggestions on how to weather-strip/insulate that to make it somewhat more air tight?
Excellent, sounds like you’re doing your homework! It’s great to have these discussions publicly so others can see the thought processes that go into “simple” things like insulating your attic. I’ve had a number of people call me and say “my contractor thought I should call you to get your guidance, but I don’t know why. I just need to insulate my attic.”
But this is a good reason to leave the walkway/floor in the attic. Last thing you need is a foot going through the ceiling.
The HVAC guys should be used to it, but they’ll certainly be cursing you under their breath
Question – it sounds like you don’t have forced air now and you’d be adding ductwork etc. to the attic in the future. You might consider having registers “stubbed in” before doing the added insulation. It does make it much more of a pain (and more expensive) to install all the ducts after a blown in insulation job. You’re also more likely to have them poorly air-seal the registers because of all the insulation.
I’m sure you’ve thought of this, but I’ll mention it for our other readers – if at all possible, you’re best off installing air handlers and ductwork in the basement rather than the attic. Doing work on attic-mounted systems is a hassle. “Hassle” translates to greater cost and increased opportunities for poor workmanship. I know this from personal experience. Virtually every attic mounted duct/air handling system I’ve seen is much more poorly installed than basement mounted systems because it’s out of sight. If you can’t see it, you’re not going to inspect it and the contractors know this, so they’ll take shortcuts.
In addition, attic mounted systems are less efficient than those mounted in the “conditioned space” of the house. Not only are the systems subjected to temperature extremes, but any leaks (which all systems have) will be outside the house. Finally, the leaks will often suck in the nasty attic air, leading to a dustier/dirtier home.
On the attic “hatch” – those systems are often a hassle. If the plywood and opening are uniform, then just some good weatherstrip installed so that it gets compressed when the hatch closes can work well. Plus, a few inches of board-foam attached/glued to the attic side of the hatch. Usually though, these hatches are pretty clunky and it’s quite tough to air-seal them effectively. If yours is like that, it’s worth re-mounting it so that you have a nice flat surface and the hatch closes with a uniform gap of about 3/16″. Then a compressible “D-profile” weatherstrip works great.
Morning Ted, I just had to let you know what great equipment this Fujitsu 12RLS is once again. Listen to this. Last night temps here were in the -1 to -3 degrees C with heavy rain and freezing rain. Overnight the temp plunged to -20 degrees C and everything froze solid. It took me an hour to get the ice off my car and I thought I had broken the wipers in the process but I guess the mechanism was just iced up and the running engine helped thaw them out. This morning temps are -15 but the killer is that the wind is 40 kilometers per hour gusting to 60. This gives a wind chill well below -30C. Now Ted these are rough conditions by any measure, the Fujitsu is unfazed by it all. Its down there in my kitchen right with output temps at 98 to 100 degrees F. I’m confident those numbers are good as I’m now using a laser pistol type thermometer which I can point right into the outlet vent. The 12RLS is maintaining my kitchen and dining area at a nice warm 72F which is what the remote is set for.
The next few days promise to be quite a bit warmer getting up to the seasonal daily average of -6C.
The Fujitsu could care less.
Regards
Jack
Ted -
I saw your video on the Fujitsu 12 RLS heat pump. One point you did not discuss is the level of noise produced by the appliance inside the house. How does it compare to, for instance, to the sound of a conventional gas furnace blower that comes through the floor duct, or maybe a standard window fan?
Thanks
Mike
Good point, thanks for asking.
If you let it run on “auto” and don’t push it to hard most of the time, that’s equivalent to low or medium fan speed which is very unobtrusive – a gentle fan sound that you tune out. Probably about equivalent to my central heating system blower and much quieter than a typical window fan. However when it is on full-blast, it’s pretty loud. Not like a window air conditioner, but loud enough that some would complain about the noise levels.
[...] Ask Ted! [...]
Hello Ted….
I just found your blog…..
For the first time in my research on the Fujitsu 12RLS I have found an answer to
a question I have had (while reading Jack Leonard’s post on the 18th) regarding
output temperature of the unit at sub-freezing outdoor temperatures.
Do you have any additional stats to confirm his information?
Thanks,
Ron
Ron,
Yep, I’ve actually got temperature sensors (input and output air) on two of my units as well as current sensors so I can see how much they’re drawing, so I’ve been able to monitor their operation continuously since installation.
The air they supply to the room is almost always between 95F-105F – quite warm even in cold outdoor temperatures. The only time the put out colder air is when they run defrost cycles, but then they turn the fan way down or off so it’s not blowing cold air around the room.
Part of the trick is that they vary the fan speed. So the temperature may be high but the fan speed is lower so the total heat delivered to the room is less as the outdoor temperatures drop. But pretty much everything I’ve seen confirms the manufacturer’s specs and it performs admirably at low temperatures.
There is one independent study that measured performance at a variety of temperatures that validates the specs
http://www.nrel.gov/docs/fy11osti/52175.pdf