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!
Note: all comments are moderated unless I’ve approved one of your previous comments. Almost everybody gets thrown off by this, but I moderate comments to avoid spammers. The downside of this is that you won’t see your comments post until I’ve had a chance to review and approve them. Sometimes this can take days (sorry!) Thanks for your patience.
Ted's Energy Tips 
Hi Ted,
I asked a question earlier today, but don’t see it, so if I’m missing it somewhere, my apologies. My question has to do with roof venting. I have a ranch with a standard gable roof. At some point a 14×14 room addition was added on to the front with it’s own gable roof tying in to the main house. The roofs are independent of each other. The addition roof has soffit & ridge vents & it’s own attic space. The main roof has soffit & ridge vents & it’s own attic space. I am concerned with where the addition was added on, I lost the soffit vents on the front side for that area. Is this going to affect my ventilation in the main attic for that area. Should the attics be opened to each other, or would this cause more venting issues? I have complete soffit venting along the rear, continuous ridge vent, and soffit venting all the way across the front up to the room addition, so the venting stops 14′ short.
Much thanks as always!
Sorry for the delay. I had an emergency that needed to be dealt with…
As far as ventilation is concerned, usually I don’t sweat it too much. More often than not, you can get by with relatively little venting if you don’t have a moisture problem like bath fans venting into the attic or big hidden air leaks from the living space up to the attic.
If you look at most houses built before the 70’s, you’ll find that very few of them have soffit or ridge vents and may only have a little gable vent and there’s no problem at all. On the other hand I’ve seen new homes that are vented by the book that are completely moldy due to other poor design choices.
If you’re concerned, keep an eye on the underside of your roof sheathing, especially during colder weather when condensation will occur more readily. If you notice any darkening of the wood, or condensation, then you should take action. What action? Look below those points to see if there’s a bathroom or passages through the walls where air/moisture could be leaking up to the attic. Adding more venting in those cases can actually make the situation worse because the vents can literally suck more moisture from the house up to the attic.
I subscribe to the old saw: “if it ain’t broke, don’t fix it.”
Ted, I have a question that could use your expertise that I’ve wondered about for awhile now. I have a ranch with a standard gable roof. A room addition (14×14) was added to the front of the home also with a gable roof that tied in to the old. There was no tear off or re-engineering the trusses, so I have two separate roof systems. The addition is it’s own enclosed roof with soffit & ridge venting, as is the main roof. They are independent of each other, as the addition was added after the main house was roofed. My concern is that where they added on the addition, I lost all that soffit venting on the front side. Do you think this is an issue? Will I get enough ventilation/air movement with only soffit venting on the rear & remainder of the front of the house in that area of the attic? Should I open the attic spaces between the main & addition roofs? Any input is appreciated as always.
Thanks in advance.
Wondering how to ask Ted a question on here?
Ask away!
Hi Ted,
We are considering finishing the basement in our house and my biggest concern right now is the best way to insulate. I’ve spent a good deal of time the last few months wading through the mess of different opinions on the subject. I’ve liked what I’ve read on your site and I’m curious to hear your opinion.
House Details
2 story
built in 1941
Climate Zone 6
The good:
poured concrete foundation (between 11″ and 12″ thick) in excellent condition (no cracks)
very sandy soil (i.e. excellent drainage)
no history of flooding (same for the neighbours, and most have been living in their homes for 30-35 years)
very low water table
The bad:
probably no weeping tile
any exterior waterproofing would be limited to an application of tar added at time of construction
has wooden members in direct contact with the concrete: 4 beam ends, the joists, a sort of rim joist on the walls containing the beams, the floor plate
one wall has the exterior grade raised to within ~18″ of the top of the foundation wall which puts grade level with the bottom of the beam pockets on that wall (the tops of the other walls are a minimum of 2 1/2′ above grade)
The previous owners had finished the basement over 30 years ago. We gutted it and discovered the following: The 2×4 framing was placed directly against the foundation wall and the stud bays were filled with fiberglass batts, then sealed over with polyethylene sheeting. There was evidence of mildew on some of the framing at floor level. Surprisingly, the fiberglass hadn’t collapsed or sunk, but some of the batts did have a slightly musty smell.
The contractor I’ve (most likely) selected is suggesting a layer of Typar affixed to the interior wall with a small air gap between it and the 6″ framing. The frame would be filled with fiberglass batts and sealed over with polyethylene sheeting. The currently favoured option from building scientists like those from Building Science Corp. and at the Green Building Advisor website is: either spray foam or foam board (2″ thick) directly on the wall, framing on top of that and no vapour barrier. My building code requires R-20 in the wall, so I would fill the walls with batts of rockwool.
What I’m most concerned with is protecting the wood in direct contact with the concrete, especially on the wall where the exterior ground has been raised. My worries with insulating are both cooling off the wall (lowering the drying potential of the embedded wood) and increasing the moisture content of the wall (by virtue of the spray foam restricting the drying potential). I’m considering placing additional columns under the beams near the wall to provide additional support to the beams. As well, the framing walls under the joists will be built to provide structural support.
One option I was considering to increase the drying potential of the wall was to run the platon on the floor 18″-24″ up the wall.
Given this situation (especially the embedded wood), what would you recommend for insulation?
Thanks in advance!
Looks like you’ve done your homework!
The good thing is after all this time, it sounds like there’s fairly minimal water damage or mold. A little musty odor is to be expected.
Your concerns are valid. I’m a bit confused by what you’re looking at doing, perhaps I’m just sleepy reading this.
You note that you’ve gutted it – does this mean you removed the existing framing or you pulled the drywall and insulation and the 2×4 framing remains and you’re building on top of that? What is the 6″ framing that you’re referring to? I’m guessing that you’re redoing everything, including the 2×4 framing, replacing it with 2×6 framing and your contractor wants to fiberglass and polyethylene cover that.
As you noted, you’re much better off foaming against the block and framing inside of that where it’s warm and low-moisture. I’ve seen this done several times with great success. I’ve never seen a wall framed like your contractor wants to do it that didn’t end up water damaged.
Your concerns are well founded. I wouldn’t want to leave wood in contact with the concrete, especially where I’d insulated over top of that. As you noted, you’re then trapping the moisture in a place where the wood would be vulnerable. If at all possible, you want:
Exterior soil |||| block wall |||| vapor retarding insulation |||| framing |||| sheet rock
If you do:
Exterior soil |||| block wall |||| framing |||| insulation |||| vapor barrier |||| sheet rock
OR
Exterior soil |||| block wall |||| framing |||| foam insulation |||| sheet rock
You’re almost certainly going to have rotten framing in short order because the framing space will equilibrate to essentially the same moisture as the exterior soil
Thanks for the quick response! I reread what I’d written about the 6″ framing and it was a bit confusing. You guessed right though: I did mean that this would be new framing replacing the removed 4″ framing.
The insulation solution that my contractor and I have agreed on is:
Exterior soil |||| poured concrete wall |||| 2″ foam insulation |||| 4″ framing (containing an additional 1.5″ of foam insulation) |||| sheet rock
Thanks again for your advice.
OK, that makes sense. That foam against the foundation walls works great. The moisture movement through the foam is so slow that it gives plenty of time for it to dry on the inside. You’d be amazed at how much nicer foamed basements are! No more musty, humid basements.
IMHO, if more people experienced the difference, every home would be built this way.
Wow that wasa fast response, thanks a ton. Your correct, we just did a temporary insulation job for the winter. I don’t fully trust my home inspector, he missed a ton of issues and I wouldn’t be surprised if the realtor gave him a kick back to sell this place. They were friends. Building codes are almost non existent here. The house was mold free prior to the renovation so maybe it’ll be best to leave the soffits alone. Either way thanks.
I’ll try to explain this mess the best I can. I bought a 114 year old farm house and had no choice but to remodel it from top to bottom. Im in the process of putting the second floor back together and have a venting question. I live north of Buffalo in New York and our winters are cold so the wife and I insulated the attic to try and save on our heating bills. I didn’t use vapor barrier and there was no drywall used yet. Come spring time and better finances I was able to get back to work and upon removing the insulation I was left with an attic covered in black and white mold, everywhere ! My house has zero soffit vents, no ridge vent and a gable vent at each end. 2×4 rafters and 2×4 ceiling joist leaving no room for an air space to use baffles. When your standing in the second floor part of the ceiling is slanted which is the roof. So you have about a five foot tall side wall then the ceiling follows the roof line for four feet then levels off to a flat ceiling. I’m 99% sure that insulating this winter a running the heat caused the mold which was my own stupid fault. If I use vapor barrier and drywall like it was before do you think it’d be ok or should I follow my home inspectors advice and install soffit vents and baffles with a ridge vent ?
Ugh, that’s unfortunate.
So if I understand, you put up fiberglass and nothing else to block air flow?
So what happened is all the moisture from your house was moving up through the insulation and out the attic. In the process, the water condensed and gave you the mold problems in the Now cold attic space.
The main thing is sheet rock with no holes to let moisture up there. In cold climates, the moisture barrier may improve it more. So you do sheet rock, then moisture barrier then insulation.
If you don’t poke holes in the sheet rock (I.E. Recessed lights) then you’re probably pretty safe so the gable vents should be fine but check building codes. They trump any advice I can give you.
Good luck!
Hello, I live on the third floor, which is the top floor except for the attic(which I don’t have access too), in an apartment that was just built and completed in October of 2012. Out of all the places I’ve ever lived (alot! including an old house), I have never had so much dust. Everyday I have to dust because it looks like it hadn’t been dusted in months. I don’t know what to do, is there anything you can recommend that I can do myself, since my landlord won’t do anything. I have an air purifier which doesn’t seem to make much difference. Can’t all this dust cause health problems? Any suggestions?
I’m sorry to hear that! That sounds like a really bad situation. I’m a landlord myself and have to tell you, if one of my tenants had such a problem, I would feel obligated to look into this because it could have serious health ramifications.
First, check the easy thing – is the blower part of your heating /cooling system in your unit? If so, you are probably responsible for maintaining the air filter. You’ll want to ensure that there’s a properly sized, clean filter in there.
Often, dust problems originate in leaky duct work. The ducts suck in impurities from the walls and attic spaces which can be very dirty. In addition, these leaks drive up your utility bill. So this may be costing you on several fronts.
Here’s what I would do to start. Get some filter material. I’ll post a link later. You’ll want to mount this in front of each of the air supply grills in the apartment. This will greatly reduce the dust problems if they are from the ducts. It also provides proof of the problem.
That’s a start. I’ll add more after a little research.
I would try material like the filter material at this link. Note that I don’t endorse this particular product, this is just an example of the type of product you’re looking for.
Here’s another similar product that you could cut to size.
Hi…I am hoping to get your opinion please.
We converted an old barn (cedar) into a cottage. It has a new roof and the ceiling has a vaulted 6/12 pitch. Contractor put the usual plywood/tar paper/composition roofing on the roof. Then came unbacked fiberglass insulation rolls (R19). No roof ridge vent/no soffets…nothing. Then came 1″ furring strips between the underside of the rafters and the inside pine T&G, because my husband wanted to run them in the same direction as the rafters… we did not put any plastic sheeting between the insulation and the pine boards…so the 6″ air space can “breathe”. There are three can lights that are supposed to be going up in the ceiling shortly. The T&G pine is obviously not going to stop air flow anyway considering everything else that was (not) done so it will do little good to remove them.
Everything I have read here for hours and hours seems to point to problems people run into in the summer with MOIST cool air meeting hot air upward….ditto for winter MOIST warm air meeting cold roofing. But our air is not moist here in Calif and there is no air conditioner in our cottage to create moisture (no house plants either)…only ceiling fans and open windows in all rooms during summer.
In the winter, our only heat source is a wood stove which produces very DRY warm air. “Cottage” is slightly drafty (because we wanted to keep the barn doors) as they look nice and wanted to preserve the barn look. The inside walls are now 1/2″ sheetrock/painted with unbacked R13 insulation rolls…probably useless because cedar is full of holes. We are not concerned about cost of heating/cooling because we rely on the wood stove for heat and ceiling fans only to circulate air in the summer.
What kind of problems do you see ahead for us? We are at the snow line…maybe get 4″ a couple times a year which quickly melts…and summer is usually no hotter than 95 degrees on the worst days (two or three weeks in Aug), but not humid at all.
Thank you so much for your time and for this site!
Thanks for posting your question. I’ll apologize in advance for a long answer because there are a number of issues that come into play. Also, I don’t intend to be overly pedantic, but since a lot of people read these Q&A’s, I’ll be discussing some basics that you probably already understand 🙂
First, vents or no vents – some of the worst mold/rotten roof problems I’ve seen have been from *vented* roofs. Things appeared to be done “by the book”, but the vents made problems worse because the vents provided a path from the humid inside air to move up and into the ceiling cavity. In fact, I’ve seen roofs ruined by adding vents. Roofs that were perfectly good for many years without vents.
Adding the recessed lights will certainly add air paths into the ceiling cavities. I personally would never install them in a tongue&groove ceiling like this and if you saw the results of doing so, you’d likely change your mind. It’s just throwing fuel on the fire.
You note: “Everything I have read here for hours and hours seems to point to problems people run into in the summer with MOIST cool air meeting hot air upward” – I hope you didn’t read this on my site because this is exactly wrong! Condensation occurs when *warm* moist air comes in contact with a cooler surface. Think bathroom mirror. You’re taking a hot shower. The hot air in the shower holds a ton of moisture. The second that hot, moist air hits the cool mirror, it condenses and fogs the mirror. You will ***NEVER*** have summer condensation problems caused by cool air hitting a warm surface. In some climates, you can have hot, humid air outside (like in Louisiana or Florida during the summer) that causes condensation problems when this hits the cool inside surface of the house that been air conditioned.
As you note, local climate is really important. A dry climate will usually have far fewer problems with rot because the dry air can carry away the moisture that might build up. However, during the winter, outdoor air isn’t the problem. Indoor air is. So if you have a cold climate, and normal moisture in the house, there’s a chance that condensation problems can still occur. This is often offset by a leaky house because the dry, outside air flowing through the house dries the air. And, with a wood stove, the air flow might be considerable, drying out the air further.
Given all this, it’s something of a crap shoot. I worked with a neighbor that had similar construction and it literally rained in the house due to moisture problems! So if you do have serious issues, you will probably notice them pretty quickly! If that happens, you’ve got some ugly solutions ahead of you. If problems are not obvious soon, you’re not necessarily out of the woods, but you could go for many years without issues.
One more thing, I strongly advise against using humidification during the winter. This can be tough if the air is so dry, because you might be getting nose bleeds, cracked skin, etc. But if you do add moisture to the air, you’re literally throwing fuel on the fire and run the very real risk of damaging your home over time.
Hope this helps some. Sorry I can’t give you a more definitive answer. The problem is, since it’s already built, there’s no simple band-aid solution. Much involves “wait and see” but don’t do anything to make matters worse.
Thanks for your answer and observations. We are still not sure if we should do a ridge vent or just leave it as it is…crap shoot indeed, and opinions vary based on roofer experience or standard protocol in our area. I am thinking that given the kind of heat we will use (wood burning stove) that this will help to keep winter moist air away (rather than propane)…as will the two ceiling fans running in reverse. We have coconut oil for skin…and dry air only kills my orchids so far…fish tank seems safe. 🙂
Summer…well, those two ceiling fans may help there too…and opened windows throughout to keep the air less moist from people breathing/cooking…even sweating hahaha. Bathroom is TINY…4×9 ft total, but I had a wall mounted exhaust fan (to the outside, not the attic) installed today that runs quietly at 70cfm to take care of shower steam. Nice 3×3 window in there to keep open too. This exhaust fan will pull air from the adjoining bedroom also, which has a 5ft sliding door which will always be opened in spring, summer and fall months.
Recessed lights will indeed add to the air paths, but T&G is not air tight and there is no moisture barrier above it anyway. We are thinking of putting 1.5″ Dow foam sheeting on the entire roof (on top of the new comp shingles) and adding aluminum ridged sheeting on that to block excess heat build up in the mini attic. If we put aluminum underlay, then the foam sheets down, then 1″ cedar furring strips, THEN the aluminum sheeting, there will also be a nice air flow yes? Keep in mind that we are now thinking at least.
Let me know if this thinking is faulty okay? I have never had to worry about the proper way to do/fix a roof in my entire 60 years…never owned a house long enough to experience any problems with rot/moisture/mold ect. But this one is a keeper and the last one we will have…getting old.
At this point, I think I should refer you to a local energy auditor. You really need to have somebody come in there and check out the situation and make proper measurements who is able to advise you based upon actual observations of your home. I think I’ve covered the theoretical basis but we’re entering the danger zone here of making specific recommendations based upon incomplete information.
One thing I will do, is a highly recommend that you take local contractor input with a grain of salt. I found it even people who been doing this for decades often have incomplete knowledge in building science. You really want an independent person with a building science background to help you out in this or you could really end up spending years trying to fix problems and makes things worse. I’ll give you one tip: if a contractor tells you “I’ve been doing this for years and I know what works”, Send him on his way! These guys, and they always are guys, are arrogant and blind to scientific evidence.
Ted, great website, love the writing and the information. I am building a 240sf addition and am trying to add some storage in the attic. I was thinking of using 2″ thermax attached to the underside of the rafters combined with soffit vents and a ridge vent. I guess I will have to add some batts between the ceiling joists.
Any problems with that setup?
Thanks.
Thanks Eric.
That sounds like a reasonable configuration. The Thermax, especially if you tape the seams, will minimize the movement of moisture and the batts will give you some inexpensive added R-value.
The one thing that can be an issue is that the attic space should then be considered part of the “conditioned space” of the house, with air flow to and from the living space. Without this, you run the risk of creating the dreaded “dead air space.” In that situation, where the attic “ceiling” is sealed AND the attic floor is sealed from the house, you have a space that gets no air turnover. Additionally, moisture can/will rise up and into the attic and could lead to a moldy environment if it doesn’t get an opportunity to flush out.
If this sounds like it is only a theoretical consideration, trust me, it’s not. A knowledgeable friend of mine created a dead air space in the attic that led to attic moisture issues. He was SURE he sealed everything, but in spite of careful work, the home’s humid air did rise up get trapped in the attic.
The key thing with all this is to treat the attic as if it’s just another living space (if you insulate in the manner you mention).
Ted,
I have high humidity in my house which was built 5 years ago. In the bathroom I can see moisture and moisture stains on the wall. When taking a shower, there will be water on the walls everywhere & the ceiling. (That’s with the fan on). The humidity all summer will be 60%-75%. Structurally the walls are wood frame, waterproof drywall, and insulation. The crawl space has a gravel floor. I think the house is holding moisture because I thought the humidity should stay around 45%-50% for optimum health. The air conditioner is sized correctly for our house. How can I fix this high humidity problem? I’ve been dealing with this for 3 years now.
Sorry for the delay in getting back to you. Went out of town for a few days…
Modern houses are usually built much tighter than older ones, so moisture issues more easily arise. Because of this, you have to be particularly careful about high-humidity situations like bathrooms. However, from your description, it appears that there’s multiple issues going on.
First, addressing the bathroom, it’s possible that there’s a couple issues causing the condensation:
– high humidity not being adequately dealt with by the fan.
– cold walls/ceiling
Have you verified that the fan is working properly? At the very least, try holding a strip of dry toilet paper up to the fan. If there’s reasonable flow, it should get sucked to the grill. This is crude test but it’s a start.
Even if there’s some air flow, it sounds like it just isn’t enough. You may have to check that the routing of the duct from the output of the fan is ok. I’ve seen some fans go 30 feet across the attic before exiting, creating such resistance that barely any air moves.
Another thing that can affect air flow is the air INPUT to the bathroom. If the doors are tight to the floor, the airflow may be restricted to the point that not much fresh air flows into the bathroom. You can easily test this by leaving the bathroom door cracked open a few inches while you shower and see if the fog moves up and out the fan.
Because of the moisture problems, be sure to keep the fan running for 15+ minutes after you shower to allow the moisture to be flushed out.
I’m glad you mentioned the crawl space. If you have any level of ground moisture, a gravel floor is a really bad thing since that won’t impede moisture flow at all. I’m actually surprised that they’re allowed to make homes with gravel crawl spaces these days. The remedy would be to have the crawl space water-proofed. This is typically done by using a couple layers of heavy plastic, sealed at the seams and affixed to the walls. Just laying plastic over the gravel is minimally effective, so if you do it, make sure to do it right – it has to be waterproof!
Do you live in a high moisture area? There are other issues that could be leading to summer humidity problems. Even if your air conditioner is properly sized, running it can actually increase humidity if the air intake ducts are leaky. I’ve seen severe moisture problems, especially when there’s attic mounted equipment and/or ducts. You may have to have your ducts professionally tested in order to track down the problems.
Hello,
Can I change my remote to read in Celsius for my two Fujitsu 15RSL2 units. Thanks
I just checked your manual and, surprisingly, it looks like there’s only an F indicator and I could find no mention of a switch or option. Strange!
Ted,
In my current circumstance, 4/12 roof in Michigan, I’m adding fg to the existing on the floor, air sealing, adding soffit baffles & a foil or bubble wrap barrier on the underside of the trusses up to within a foot of the peak but not sealing off the ridge vent. Is there any advantage to running soffit baffle further up the trusses & installing fg in the truss cavity behind the radiant barrier?
Much thanks as always!
I probably wouldn’t bother with the extra FG at that location. It could make a little bit of a difference in the summer when you get the extreme heat radiating down from the roof, but the foil under should do that quite effectively (though this will diminish as it gets dirty over the years). But really, I’d focus on the main attic floor insulation and air sealing.
Hi Ted,
I came across your site while preparing to insulate my attic. My current situation is thus: My 35 year old townhouse in the suburbs northwest of Philadelphia has ~4-6 inches of loose fill insulation throughout. The middle of the attic floor has plywood over the joists, and from what I can tell, also has insulation under it. The attic ceiling has been drywalled over all the way to the floor except for a small space between four of the rafters (out of two of which the attic fans appear to be vented), but there is nothing between the drywall and the roof. I have a attic stair cover that I built out of rigid foam board insulation. I don’t have any recessed lighting, but there are there are three ceiling fans that were installed below I am looking to increase the insulation from the current ~R11 to around R49 and am planning to blow in using a rental machine. I’m also trying to decide whether to blow in over the whole plywood floor or whether to create a small ‘wall’ of sorts and leave at least some of the space around the attic stairs for storage. I would welcome any thoughts about my specific situation.
edit: Apologies, I meant bathroom fans when I said attic fans.
Summary:
Attic floor is insulated to about R-19 and floor is covered with plywood in middle
“Ceiling” is sheet-rocked and uninsulated
This is a common construction in our area. I’m glad that you’re thinking ahead before jumping into it.
Once you blow in insulation, doing work up there is a real pain, so best to do as you’re planning and seal up all the trouble-spots you can find. I retrofitted a townhouse just like this. To simplify the work, I pulled up the plywood floor because there were some pretty big energy holes hidden under them. Afterwards, I just screwed them back down with a few screws to make it easier to do work up there as necessary.
A few areas to pay attention to:
Look around the attic for any black insulation. That’s a dead giveaway of where air is leaking up from the house and through the insulation. Dig through the insulation and find the hole! It’s like looking for Easter Eggs! Hint – if you have recessed medicine cabinets (cut into the wall sheetrock), pay attention to that wall in the attic. Some of the worst energy holes can be found there.
I also like using canned foam to seal the holes through which electrical wires poke from the walls up to the attic. It helps reduce mouse movement and slows down the spread of fire. It’s required by code these days but I’ve seen very few homes where these holes are sealed up.
As for your question about creating an insulation wall – definitely do so. You’ll be glad you did later. You may also wish to minimize the amount of the floor that is covered with plywood. Sometimes they go crazy with it. If you’ve got more than one plywood width by a couple long (say 4’x16′) then you’ve got too much in most cases. Use as little as necessary to facilitate safe passage, then build your insulation walls and fill the rest of the attic with insulation.
Note, as usual, if you have soffit vents and a ridge vent, be sure to install baffles and insulation dams to allow free air flow from the soffit up to the ridge vent. It sounds like the drywall already provides the vent space, so you just have to prevent insulation from covering the soffit vents.
A final thought – if the current insulation is as high as the floor joists, you might consider just laying unfaced batts over the joists in the other direction instead of blowing in insulation. Blown in is easier/faster, and I’ve done it both ways, but I always hate having blown in for those times that I have to go up there and run another wire or do other work in the attic. It can be a real pain! You may also want to look into Bonded Logic insulation. I did a few jobs for friends and family with this stuff and LOVE it. No itchy fiberglass. No blown in mess. You can get it delivered from the good people at Green Depot in Philly. It’s a lot more expensive than fiberglass, but it’s a joy to work with and it’s much denser than fiberglass so it can help a bit with free air flow and convection currents. Good stuff!
Ted, thanks for you detailed, useful response. It looks like I need to do some additional prep with all of the sealing work and pulling up some of the plywood before I actually blow-in or lay down the insulation.
My pleasure. I’m always happy to share to help others avoid some of my own mistakes 🙂
Andy – regarding removing the existing fiberglass with brittle vapor retarder paper backing:
The short answer is no, don’t bother replacing it.
The longer answer:
In general, that paper has done little positive for you even when intact. Pretty much any water vapor that gets through the ceiling and into the space under the batt is going to find its way into the attic. Why? Studies show that the moisture movement through a painted ceiling is vastly lower than through any holes or cracks that directly let air flow. In fact, there’s a movement among building scientists to eliminate the requirements for vapor retarders in most climates because they often do more harm than good!
For example, the rule is, the vapor retarder should go on the WARM side, usually facing inward toward the living space of the house. This is to avoid condensation since condensation forms on the cold side. But a lot of people mistakenly install batts upside-down, thinking the paper should face up to keep moisture out of the house.
More troublesome is that the “warm side” changes from season to season! During the summer, the warm (and humid) side faces the attic. Now, the moisture goes down through the fiberglass, hits the colder paper (near your air conditioned ceiling) and can condense, leading to water damage. In reality, this is only a problem in extreme climates like Florida, but it does happen.
Hope that helps put your mind at ease.
Hey, Ted – We seem to be having some trouble with air movement in the house. In these cold temps, that’s not a problem that can go unresolved but it’s proving tricky to figure out where the problem is. The house is completely sealed with spray foam insulation (walls, ceiling and crawl space), we’ve done the candle tests around doors and windows and there are no indications of a problem there. The gas fireplaces are closed (no chimney); we’ve even closed all the doors to bedrooms and bathrooms and shoved towels under them. So what’s the problem? When we light candles, the flames dance like crazy and, no, we’re not moving around to cause them to. What more can I do to trouble shoot this? I’m very aware that the heat pump is working overtime (and, yes, I know cold weather will do that, lol). Any help you can give us is greatly appreciated!!!
Sounds like you’re a real sleuth!
Let me see if I understand your question – sorry if I’m being dense 🙂
I think you’re asking about drafts and the clue is that candles are dancing around indicating air movement. I’m also going to assume that you’re having some comfort issues because of the air movement/drafts?
Since you mention the heat pump, I’m also guessing that you’re doing the “candle test” with the fans turned off. That would be too easy.
Does the candle movement vary much room to room? Are you finding any patterns in when/where the candles flicker?
My first guess would be convection currents. They can be pretty strong. Even more-so with high ceilings. It’s pretty amazing how strong they can be! They’ll be stronger under any area which is particularly cool, such as near windows or below skylights. Any cold surface will amplify the process as the heated air gets cold and drops to the floor, pushing other air around and so forth.
Here’s a test that I just thought of. I’ve never tried it but it sounds worth trying! When you’ve got a candle flickering, possibly due to these cold downdrafts, open an umbrella (I know you’re not supposed to do that in the house but put superstition aside for a moment in the name of science!). Hold the umbrella over the candle and see if that reduces the effect. If it does, then you’ve found which direction the air is coming from. If not, you could try holding the umbrella at various positions to see if you can block the airflow which would stabilize the candle flame. At least that should give you some hints as to where it’s coming from.
Give that a shot and let me know how it works. I love a good mystery!
Hi Ted and all,
I was in touch last year with questions about the Carrier Greenspeed Heat Pump. This summer we replaced our steam oil system with 2 Infinity Greenspeed Heat Pumps, and I wanted to report back.
We have a 3 story big old house in Boston. It was built in 1906. The previous owners blew in insulation. Our square footage is around 3000. We installed one 3-ton pump for the first floor, and a 5-ton pump to cover the 2nd and 3rd floors. One of our requirements was to get 3 zones– one for each floor. Our previous system was 1 zone.
So, the system seems to be working very well. It has been unusually cold here since the start of January. We don’t have any back-up system that I know of (I could be wrong about that), but there has never been an issue with it getting our house warm even in the single digits. It comes on so quickly and heats the house really fast if you want it to. We try not to ask it to jump up several degrees at a time, because I think this is less efficient.
We didn’t have much experience with the a/c side of things since the installation was in late summer, but the times we used it, it seemed fine. Well, awesome, really.
Our a/c guy quoted us $29,500. This included installing ducts but not electric work which was another $3000. I think the job probably would have cost more, but there were so many screw ups during the installation that I think our guy didn’t dare ask for more. I know he didn’t make any money on it. He had never installed these heat pumps before, which may have contributed to some of the problems (not all though).
I’ve gotten 2 electric bills so far (where we were using the heat pumps significantly). The first was for the month of November and was $325. But if you subtract the amount we used for electricity pre-heat pump last year, it’s $202. The average temperature outside was 43. We used 1763 kWh.
December’s bill was $377 if you subtract the additional electricity we used based on last year’s bill. Average temperature was 32.
Over the 4 winters we’ve spent in this house, our oil heating bill was about $2500/year. This was for a cold house, about 60-62 degrees. Now we are comfortable because we can warm just the area we are using. The kitchen has extra vents and is regularly 68-72. The rest of the first floor is more like 64. So I think we are doing quite a bit better– maybe not as miraculously better as I thought though.
That said, we have 2 issues to resolve. One is that the unfinished basement is now freezing. The old oil furnace used to kick off enough heat to keep it at least in the 50s. Now it is regularly about 40 and even dropped to 38 during a cold spell. I am thinking that we can maybe add a vent to add some heat to the basement, but we haven’t addressed this yet.
The other issue is that the heat pumps are very noisy when they are working hard. This is quite often when it’s below 20, but it also occurs even in the 30s. It sounds like a truck is idling outside. Or at times there is a higher pitched sound kind of like an airplane flying overhead. It’s loud enough to hear inside the house, and it’s loud enough that our neighbor (who’s house is very close) has complained. So we are looking into a fix for this. Maybe an acoustic fence? If anyone has any suggestions on how to dampen the sound, it would be greatly appreciated.
All in all, I think? it’s been a good decision. Or maybe the jury is still out. We are plenty warm and cool though.
We got a $25,000, 7-year no-interest loan from the state (Massachusetts). Also $800 in rebates. Maybe another $300, too, coming. If we had timed it better Carrier was offering a $1000 rebate on the heat pumps in June and again in September. So this is definitely something to pay attention to if you’re considering getting one.
I would be happy to talk to anyone who has any questions (alavigne31@gmail.com). I never was able to talk to anyone who had this system before we got it.
Best,
Annie
Thanks so much for checking back in and sharing all this info! Not many people have risked the GreenSpeed because there’s not many testimonials like this. From the sounds of it, the system is working well, especially in light of the frigid weather we’ve been having. Even my geothermal is struggling these days!
Your unfinished basement temperature is one of those “unforseen consequences”. Adding a supply vent or two down there would help. It’s amazing how much heat most systems throw off to their surroundings. I figured that my old oil system was losing about 30% of it’s efficiency by bleeding away so much heat to the basement utility room which was open to the outside (as many are).
The noise is a concern. My small variable speed Fujitsu units are really quiet so I’m surprised that the GreenSpeed units are so loud. Their advertised as being quiet and having superior noise shielding so this doesn’t sound right. However, when I Google it, I do see a number of people complaining so perhaps this is a “feature” that they don’t tell people about. I hope they find a fix for you because this sounds more than a little annoying.
There are some good tricks for sound deadening, such as thick hedges. The key thing for sound reduction is to avoid hard surfaces that reflect the sounds. It’s also important to use materials that can’t be induced to vibrate at the same frequencies as the unit. Again, thick hedges can be a very effective starting point. Just be sure that they’re far enough away from the unit that they don’t impede air flow. There should be information in the installation guidelines that tells you how far away you need to keep barriers/foliage. I would guess at least 24″ on all sides but definitely check your manuals and ask your installer what the manufacturer specifies.
Thanks again for writing.
-Ted
Hi Ted – We’re in DelCo. New construction, looking to use a Carrier Infinity heat pump with a propane back up furnace. (No nat gas.) Since we don’t expect to actually need the furnace that much, given the high efficiency of the Infinity HP, wondering what the cons would be to using a standard Comfort Carrier furnace. Asked one dealer, and his response was that he recommends matching series with Infinity HP & furnace, but not too convincing… Thoughts?
– Christine
This depends on a number of factors. Typically, even high efficiency heat pumps are set to switch over to the furnace at a fairly high temperature, i.e. 30F-35F. IMHO, with high efficiency units like yours, they can use larger heat pump capacity and reduce this switch over temperature to 20F-25F which makes a HUGE difference in the consumption of propane. So that’s one question to ask your installer.
Assuming the normal sizing equations, you’ll be running on propane backup quite a bit. This winter, we’ve had quite a few days of low temperatures where you would have been running exclusively on the propane. At the typical cost of propane that people are paying, this would add up fast. To answer this accurately, I’d really have to look at the price and efficiency difference between the units you’re comparing. Typically for these units, we’re probably looking at about a 10% efficiency boost from the high end furnace. Let’s use a round number of 1000 gallons of propane for the entire winter. At $3.50/gallon, that’s $3,500 in propane and a 10% saving which is $350. If you figure on 5 years as a reasonable payback, then that’s a savings of $1,750 (excluding inflation). So, simplistically, you could use a calculation like that to figure whether it’s worth it.
Likewise, by upsizing the heat pump, which often costs only a few hundred dollars more, you might save better than 10% on your propane use. So it’s quite likely that you’d be better off going with a size larger heat pump and stick with the standard efficiency furnace.
As you can see, it’s a lot of variables in the calculation but back of the envelope, I’d tend to go larger heat pump and standard furnace based on these very rough assumptions.
Hi Ted,
We keep getting hammered by the PECO bill, despite doing some things we thought would improve efficiency like new siding, new windows in part of the house and a new roof in the past 2 years. Not to mention a new hot water heater last month. We rank #98 out of 100 similar homes in efficiency, according to PECO. Not good. Apart from replacing more windows, where should we start?
Thanks, Matt
ok Matt, I’ve started a post here for our discussion:
Ted, I must say, your site is awesome and a great source of info for addressing many of the issues with my crawlspace, basement & attic.
In regards to my attic, I have a home built in the early 70’s with a 4/12 pitch roof in Michigan, so we experience temperature swings from 80-90 degrees from summer to winter. I am in the process of insulating the attic. There is currently only about 4.5-5″ of fiberglass batts (R-19?), which runs out over the top plates with no baffles, so there is no air circulation. I have addressed that by installing baffles in every rafter bay & I have continuous ridge & soffit vents now. After reading many of your articles, I am going to more diligently air-seal the attic next time I am up there. I’ve been doing good so far, but am going to be meticulous with recessed cans, light boxes & top plates. The trusses are standard web trusses and the area will never be used. It could only be used for storage, and that’s assuming anything I put up there would have to fit through the attic hatch, and with it being a standard 2×4 web truss, the bottom cords are really designed for holding any additional weight. So the only time I go up there is for running wires, installing new lights/switches, or currently insulating. I have a garage full of R-30 unfaced batts that I have begun to lay perpendicular on the existing insulation/rafters.
Before finding your articles, I was planning on installing foil-faced polyiso on the bottom of the rafters to help separate the bottom of the roof deck from the interior of the attic, in hopes of making the space not so extreme of a temperature swing from the conditioned space for efficiency purposes. But my concern was how would any moisture that made it’s way into the attic then dissipate, if there was no active air movement. And your thoughts on dead spaces confirmed this concern.
In my case, if I were to seal the bottom of the rafter bays with polyiso, would I also need to seal the floor with polyiso to keep any moisture from entering the attic at all? Or is it best to simply air seal any penetrations into the attic and pile on the fiberglass?
I highly value your opinion in this arena and look forward to your response.
Thanks for reaching out. I always appreciate the feedback!
Sounds like your climate and house is similar to mine. I went through the same thing when I moved in though we had an even smaller amount of blown in shredded fiberglass. Went through the same thing – installed continuous soffit vents to match up with the ridge vent. That’s no fun on the 4/12 roof! Did you experience the dreaded shingle nail in the scalp? I cursed that low pitch roof many times!
I would probably skip the poly-iso under the rafters for the reasons you note. OTOH, using doing a quick and easy foil or “bubble wrap” radiant barrier would significantly reduce the summer attic temperature while allowing airflow and moisture escape out the ridge. To clarify – you wouldn’t be going for an air-tight barrier like you might with poly-iso. You’d leave a gap at the top, maybe 1 foot, so air could flow out the ridge from the attic space AND from the soffit vents, up the rafter bays and out. I did something like this in my garage attic and it makes a world of difference in the summer without risking the moisture issues.
As you noted – your most practical approach is to simply air seal the attic floor (and high hats) and pile on the fiberglass.
cheers,
-Ted
Ted, thanks immensely for the reply. Glad to know I’m on the right path! The current fiberglass is original to the construction of the house, it’s actually yellow instead of the standard pink. The paper facing is very brittle if it’s disturbed I’ve found. Would it be advantageous to pull out all the existing fiberglass and put down a vapor barrier of some sort (poly?) foil taped to the rafters? Or do the potential savings not out weigh the required time & expense?
As always, much thanks!
Thanks for your input. Will keep u posted on our progress.
After more research and reading, we decided to expand our install to include our 4-season room which has just a propane free-standing fireplace for heat which we can’t use when our grand kids are around. We are looking at one to one units – 18,000 for kitchen and open family room, and two 15,000 units, one for our large master bedroom and the other for the 4 season room. Torn between the Mitsubishi and Fujitsu brands – pricing and guarantees are the same, energy efficiency very similar, and all qualify for rebates. The installer has more history with Mitsubishi and that’s his pick, but isn’t pushing us one way or the other. Your thoughts? Couldn’t find much on line, but the unit specs are very much the same, also features from what I could gather.
Mitsubishi is a very solid, reliable brand and if all other considerations are essentially equal, I’d go with that. Especially if your installer has more experience with it. You don’t really want them learning on your install – I’ve made that mistake before and it can be ugly!
Good luck on your renovation – sounds great!
Hi Ted – Stumbled upon your excellent site while researching Fujitsu heating/cooling system that we are considering. The area energy efficiency firm is proposing a 36,000 condenser with two 18,000 BTU HFI heads.which do not qualify for rebates, loan programs etc. because of the EER rating of 8.8. The original plan was for two 18,000 condensers and 3 heads, but for aesthetic reasons, we decided against installing that 3rd head. According to the advisor, the larger condenser is slightly less efficient for cooling but more efficient for heating than the two smaller units. Those did qualify for the Energy Star program. Our primary focus is on saving on heating, but saving on cooling would be nice too. Now I am concerned that we may be saving a bit up front but will be paying more in operating costs. Our electric prices out at almost 20 cents KWH.- your thoughts?
Also, we will be installing these outside under a deck in our pool area. I wasn’t able to find the sound rating anywhere on the company website. Should I be concerned about noise while we are outside by the pool during the summer?
Thank you Nina.
Nina,
I personally haven’t used the dual-headed units, however my brother and others I have talked to have tried this configuration and been very happy with them.
Since you’re focussed on heating and that’s where it’s most efficient according to your installer, then you should be good. The efficiency for air conditioning should be more than good. Also keep in mind that if you’re in a climate that requires less air conditioning, the system won’t have to work as hard and the variable speed compressors on these units run very efficiently under these conditions.
As for sound, I’m always amazed at how quiet they are most of the time, especially if they’re running at low capacity. I’ve got two of my units behind a small fence near my pool and I really have to listen to hear them running. Of course, if they’re running full-blast, you can hear them, but they’re nothing like the big central air systems we’ve all come to know and hate. 🙂
Thanks for the prompt reply. Great information. Feeling a bit more comfortable in moving forward.
Ted, what do those like me do to convert from oil to natural gas on an old fashioned steam boiler/burner one pipe system? A couple of brands I’m being shown, none above 82.6 AFUE. And the cost of conversion seems I am being gouged due to popularity of convesion, huge mark-ups.
There should be plenty of options but since they use totally different combustion systems, you’re most likely looking at a completely new boiler. Such a replacement in my area runs anywhere from $5,000-$15,000 depending on a variety of factors. But you should be able to get a basic replacement done for the low end of this scale.
If you’re existing system is old, I would not recommend an oil-gas conversion kit due to potential issues with the age of the equipment. Things like rusted heat exchangers etc. can be a real problem.
Another thing to keep in mind is that the chimney will almost certainly have to be relined or an alternate venting system installed. This is due to differences in the temperature and amount of flue gases. A modern condensing gas boiler vents through PVC pipe, usually close to the boiler and out the side wall. This is much less expensive than relining the chimney which can cost a couple thousand dollars. So keep the total replacement cost in mind when comparing upgrades.
There are other options to think about too, like using an indirect water heater attached to the boiler if you don’t already have that type of system. Now’s the time to do it so it can be designed in from the start rather than patched in later. Often, the salespeople will slip that on the quote automatically, which adds several thousand dollars to the price so it can be hard to compare apples to apples. It’s most informative to have them quote a couple options:
1 – straight replacement including whatever venting options are required to make it work using a base model (i.e. 82 AFUE)
1a – same as above using a high efficiency condensing boiler (typically ~92 AFUE)
2 and 2a – the above adding an indirect water heater
One final suggestion – get a subscription to Angie’s List and choose highly rated contractors from there. That’s the only review service I’ve found to be relatively reliable for HVAC contractors. It can be very difficult to separate the good from the bad on your own, so having a resource like that is invaluable.
Thanks for your input. A few more pieces of info. The house is in WA state, about 30 miles north of the Columbia river, just above Hood River OR. Elevation is about 1700 feet and humidity typically runs between 35 to 50 percent according to my humidistat, doesn’t seem very high. For heating and cooling the game room, we have a mini-split heat pump. We are currently leaving the heat pump off and the windows open, thinking that less temperature differential would cause less condensation. I did try running the mini- split on a de-humidifying setting but didn’t notice any difference. Is there a chance that the building materials including the decking are still drying out as the building is new? It did sit all last winter before the roofing was on, with only a tarp over the decking…. Snow on the tarp all winter. Could we be still pulling moisture from the garage cement slab below? No one around here seems to understand what is going on. Insulation guy has never seen this before with similar installs.
One question was whether we should have installed a vapor barrier below the insulation and rafters but above the t&g. From what I understand the answer is no because the insulation guy installed solid foam panels with caulking from the inside up against the decking before blowing in the insulation.
Any other suggestions or comments?
That’s good information. A couple of thoughts:
I’ve got several mini-splits and have had issues with their humidity removal at “normal” temperature settings (i.e. 72-76F). I’ve found that unless you turn the mini-split temperature down to 66-68F, it is not effective at removing humidity. Even though it won’t pull the room down to those temperatures, it does a much better job of dehumidifying when set to a low temperature. I did some recent troubleshooting on another home (mentioned in my other reply) with excessive humidity, and all that was needed was changing the set point from 74 down to that 66-68 range. Especially at the dehumidfier setting, get aggressive with the temperature (i.e. very low settings) since the unit runs so low, don’t worry about energy consumption.
However, this is only one part of the story. As you noted, if your humidity is relatively low, then you’d have to look for other sources of water entering your living space. Drying of the slab is certainly a possibility. They’re supposed to cure for some time. See this link. If your home is relatively tight and the slab or other building materials retained a lot of moisture, then it certainly could be evaporating into your living space. Do you have a moisture gauge in your home? You can get them inexpensively ($20). I’d measure the humidity in the garage space as well as a couple other areas around the house (from low spaces up to high) to see what the relative humidity is. You definitely want to keep your house in that same 35-50% range.
Out where I am, it’s often hard to keep it below 60% during the humid summer, but with your conditions, I think you should be able to keep it lower. If the inside of your home is higher, than there’s got to be an internal source of moisture. You don’t have lots of plants, do you? Go room by room, looking for anything that could be significantly raising humidity. Whole home humidifier attached to your duct system? Showers without adequate venting or non-function vent fans? Humidity coming in through foundation walls from a high water table?
I’m quite certain that you’ll be able to figure this out. It takes a LOT of humidity to cause summer condensation in your house.
Regarding vapor barriers – Normally, I’d say yes – you’d want vapor barrier behind the T&G. But since you’ve got the foam board up against the underside of the deck, you’d effectively end up creating a double vapor barrier (even though the foam board is slightly vapor permeable). That would leave the insulation filled cavity as a dead air space which is usually a bad thing. So I agree with your assessment. Best to keep it single sided. Note too that this would have nothing to do with your current issue and is much more of a concern during the winter.
Keep posting. Let’s beat this problem!
Ted,
Wanted to also let know that the garage is actually a separate building so it doesn’t pull any moisture from the house or house contents. It is set back into the hill side some. The NE corner has about a 7 foot cement wall at the garage level. Going both west and south, it slopes down to the garage entrance level. Garage entrance is from the West side. Hillside has lots of water with springs in the vicinity although we have never had this problem in the house.
Ken
It is possible that large amounts of moisture is coming through the foundation walls if that’s the case. It will be interesting to get humidity measurements throughout the house.
If it turns out that the moisture is coming in through that area, you could look at a couple of options: “waterproofing” and ventilation.
While I’m not a huge fan of the waterproofing paint for foundation walls, because it can simply get blown off by the pressure of the water vapor (it can be huge), with the right treatment, it can considerably slow down the movement of moisture.
Ventilation is easier – provide active ventilation of the garage space with fresh air, using a humidity activated fan and a louvered air intake vent positioned so that air can move through the garage and flush out the humidity. But I’d only undertake options like these if the humidity measurements proved that there was a lot of moisture in there that could be migrating up and causing these problems.
We are having a new garage built with a game room above the garage with cathedral ceilings. We have chosen to use blown in insulation which filled the rafter bays. Before the insulation was blown in, one inch foam boards were laid against the roof decking from the inside and caulked. I pre-finished all the T&G including the groves and lips with two coats of sealer/finish. T&G was installed without an additional moisture barrier. We seem to be having some moisture collecting at the peaks during hot days in the summer. In the mornings the ridge beam is dry but by mid to late afternoon on a hot day, the ridge beam is moist to the touch. I had the contractor leave the last several rows of T&G at the peak off until we figure this out. Last time I checked during the heat of the day, there was moisture collecting near the peak on the room side of the T&G but the top side was dry. Their was moisture also collecting on fabric holding the insulation in where the T&G had not yet been installed. What is your assessment of my problem and what can I do about it now??
Now that’s a different problem!
Typically, moisture issues arise during the winter or other cold weather because cold surfaces cause moisture to condense on them. During the summer, usually, things are warm enough so that condensation isn’t possible except under very humid conditions.
The reason the top of the T&G was dry is because it’s warmer (it’s facing the hot roof) and slightly insulated by the wood itself from the cool, air conditioned air inside.
The positive aspect to this is that the moisture problem doesn’t appear to be hidden inside the ceiling cavity.
Another bit of physics – humid air rises because it’s less dense than dry air. This is probably why you’re getting moisture at the peak of the ceiling and not lower on the walls. However, this is all pointing to an extremely high humidity in the house. High enough that it is possible to end up with other issues, like mold growth. You’re going to have to do some detective work to determine why it’s so humid.
I’m assuming you have and use air conditioning. It’s possible that the system isn’t dehumidifying properly. This can happen, for example, if the blower on the system is set to run all the time. This can defeat the dehumidification that the air conditioner provides by re-evaporating the water off the coils instead of letting it drain off and out of the system.
Another reason that air conditioners sometimes don’t dehumidify well is if they don’t run enough. For example, if it’s a hazy, humid day, but not too hot. Maybe the air conditioner won’t turn on or will run infrequently. This happens in my own home fairly regularly. We might leave the doors open in the morning for the dogs. But before you know it, it’s horrible and so humid in the house that condensation is building up. Then we close the house and run the air, which now has to work overtime to remove all that moisture from the air! It’s actually much better just to keep the house closed up and the air conditioner running on mornings like that. My rule is, if you go outside and it feels “muggy” – close up the house and run the air.
Finally, I just helped a friend with a similar issue – the house was very humid, both from our climate and from moisture entering from an old, dank basement. The solution was easy – turn the air conditioner thermostat down a few degrees, forcing the air to run more. Sure, it costs a bit more to keep the house colder, but it is so much more comfortable now that the humidity is being removed. We’ve all been trained to set our thermostats to 78F and tolerate the higher temperature but this often leads to horrible mold (or health) problems and uncomfortable homes. That advice is ONLY good for people living in dry climates.
If any of these things sound familiar, you should be able to rectify your situation pretty easily by simply lowering your thermostat. You can double check that the air conditioner is dehumidifying by locating the condensate drain outside your home (if you have one) – there should be a fairly steady drip while the air conditioner is in use, especially if your house is that humid.
Let me know what you discover 🙂