Monthly Archives: March 2011

Types of Insulation: Part 2 – Where does insulation go?

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In part 1 of this series, I gave you an overview of the different insulation materials and the various forms they come in. This article covers where insulation goes and why. Knowing this helps you understand why you’d want to use a particular type of insulation for specific applications in your home.

Where do you use insulation?

  • On the attic floor
  • In attic cavities
  • On an attic knee wall
  • On the attic ceiling
  • In the walls
  • Around the windows and doors
  • Around pipes and other holes in the wall
  • In the basement and crawlspace ceilings
  • On the basement and crawlspace walls
  • Under the slab
  • Outside the foundations

Each of these areas really deserves an article of its own. In fact, if you look on the Building Science website, you’ll find highly detailed articles doing exactly that.  If you want to go straight to the source, consult these references.

Let’s look at some photos to get an idea of several of these cases…

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The Energy Geek Video: Sun Tubes and Skylights

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My first Energy Geek video! This is the companion video for the recent article on Sun tubes.

Don’t expect much production quality. These videos will be like this blog – unedited, not politically correct, lots of opinions. So if you’re expecting “This Old House” you better look elsewhere!

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FAQ for Solatubes

Q&A – Types of Insulation

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Bonded Logic Denim Insulation

When you insulate your house, you’re going to be confronted by a dizzying array of choices. How do you know which one to use? How much do they cost? Are some better than others or is it all hype? In this article, I’m going to do my best to sort through the options and help you make sense of them. Be warned – there’s a LOT of material here, so I’m going to have to break this into several articles.

First, let’s survey the types of insulation that you’re likely to encounter. I’m also going to provide links where appropriate.

  • Fiberglass – batts
  • Fiberglass – dense batts
  • Fiberglass – compressed
  • Fiberglass – shredded / loose fill
  • Fiberglass – Johns Manville Spider – sprayed in
  • Cellulose – loose fill
  • Cellulose – damp sprayed in
  • Cellulose – dense packed
  • Spray foam – open-cell, Icynene
  • Spray foam – open-cell, soy based
  • Spray foam – high-density closed-cell
  • Spray foam – high-density closed-cell, soy based
  • Board foam – expanded polystyrene
  • Board foam – extruded polystyrene
  • Board foam – polyisocyanurate
  • Board foam – foil faced polyisocyanurate
  • Denim – Bonded Logic batts

This list is long enough. There are other insulation materials that have been used over the years, from vermiculite to horse hair to rice hulls to straw bales, but I’m not going to touch on anything that isn’t commonly available in the United States. Sorry!

Insulation Characteristics

Before we go into analyzing all the details of insulation materials, let’s spend a moment defining the basic characteristic of insulation – the R-value.

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Mini-review: Bosch Ariston 4-Gallon Point-of-use Water Heater

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Does it take a long time for hot water to get to your sink? Do you think that it’s wasteful to run the water for a minute or two just to be able to wash your hands? Have you thought about installing a recirculation system for instant hot water? If so, this unit might be for you.

I had all these issues in my kitchen because the kitchen water run is quite a distance from my main water heater. So we just got used to washing our hands in cold water. And if we had to rinse some dishes and some needed hot water, we would turn the hot water on full and wait…and wait…and wait until some hot water came out the faucet. I knew there had to be a better way.

For years I’d researched water recirculation units and found one, the Chillipepper, which people seemed to really like. However, I have granite counters and no convenient place to drill a hole for the power switch. I also have other fixtures on the kitchen water line and I didn’t want my wife to have to remember to push a button and wait for hot water. Finally, because I have long pipe runs from my water heater, this still wouldn’t solve the problem of wasted energy because gallons of hot water would be left in the pipes.

After doing some calculations and determining that any solution using the main water heater would waste several times as much hot water as a point-of-use unit, I broke down and bought one of these mini-water heaters.

Our house has a utility closet in the basement that is directly under the kitchen, so I mounted the unit in there. Plumbing was easy for me, but I’ve done a lot of plumbing work. Most people would need to hire a plumber to install the unit. But because of its size, installation is a snap.

Some people will plumb the cold water intake to the heater from the hot water feed to this part of the house. There’s some logic in this, in that if you need lots of hot water, this heater can provide quick water for hand washing but if you need more water, it flows into the tank and provides you with a much greater supply than this little heater can provide. However this still leads to a lot of wasted energy because you’re leaving all that hot water in the long pipes every time you use a little water to wash your hands.

Instead, I chose to connect it to the cold water supply. My logic was that the kitchen sink really should not be used for long washing sessions. rinse a stubborn dish or wash your hands and that’s it. I also had an ulterior motive – if there was only a few gallons of hot water available, it would force my family to use less hot water. Additionally, our washing machine is on this water circuit, and I prefer washing in cold water but my mother-in-law, who likes to come over and do our laundry (don’t ask!) is old-school, and insists on setting the washer to ‘hot.’ Now she gets the satisfaction of thinking she’s washing in hot, but I know the water heater can only supply a few gallons of hot, so it ends up providing the first few gallons of hot water for the primary rinse, but after that, it can’t keep up with the demand. I consider this a bonus energy saving!

The unit uses normal 110v house current, so you just plug it in a nearby outlet. However, I would recommend a dedicated circuit or one that doesn’t have other heavy loads on it because electric water heaters pull a lot of juice. If the water heater turns on at the same time as you’re toasting some bread, you’ll blow a circuit breaker. So make sure you plug it in an outlet on a circuit that is lightly used.

As far as heaters go, this is an attractive unit. As you can see in the picture, it has a white plastic case. Nothing special, but not just an ugly metal box like most. But really, it goes in a utility closet, so they could have painted it any color they wanted and I wouldn’t have cared!

Does it Work?

The main question is: does it work? The answer is “yes,” up to a point. We can now wash our hands and run the dishwasher (which has it’s own super-water heater built-in). As noted above, it also provides hot water for our front-loader washing machine, but because of its limited capacity (four gallons in this case) it won’t provide a lot of hot water. You can wash for a minute or two before the water runs luke-warm then cold. This can be a plus or a minus depending on your needs. I know some people would find this objectionable. But that’s just the way these things work. They enforce water conservation and force you to change the way you use hot water. If you don’t like this, then a small point-of-use water heater is not for you!

Energy Savings

Like all good geeks, I measured the actual electricity use of the water heater. Because it just plugs in an electrical outlet, I plugged it into my kill-a-watt meter, and make daily measurements to see how much energy it is actually using. I’ve been very pleased with the results so far.

Under normal usage – rinsing a few dishes and regular hand washing in the kitchen sink, it consumes 1.5 to 2.0 kWh of electricity per day. This is about 1/3 the electricity that would be required if I used the main electric water heater and just “lost” the heat in the pipes every time I used the sink. On laundry days, this consumption increase by about 2-3 kWh (about 20 gallons of hot water). So we’d still be better off always washing in cold water, but some habits die hard….

Conservatively, I project that for my family, with it’s modest hot water needs, this unit is saving me about 4 kWh per day (about 25 gallons of hot water). That may not sound like much, but over the course of a year, that’s 9,000 gallons of hot water and about 1,400 kWh of electricity. For most people, that’s a full month of electricity saved every year. In my area, that’s a saving of $232! I’ve checked on Amazon.com, and this water heater cost $169 when I wrote this article, so it pretty much pays for itself in the first year if you install it yourself. If you hire a plumber, it may take a couple years to pay off. And, I haven’t included the ecological and financial cost of the water you’re saving.

Addendum – this is not an “on-demand” water heater

To avoid confusion, I should add that this is not an on-demand water heater. On-demand water heaters use much more powerful heating elements to heat water on-the-fly. They provide an infinite supply of hot water because they heat water as needed. The Ariston water heater is just a miniature storage tank water heater. So it’s the same as a conventional water heater, but tiny.

Support my continued work. Buy it here on Amazon.com

Note on my Amazon store

Like any informed consumer, it probably raises red flags when you see someone reviewing an item then potentially profiting from it. I couldn’t agree with you more. For years, I refused to profit from any of the products I’d recommend to my clients for fear of conflict of interest. But then my wife convinced me otherwise. She said “you’re recommending these products because you buy them and believe in them, not because somebody is paying you to do it. How does it compromise your principles by gathering the products you recommend into one convenient place?” How could I argue with that logic?

So now, whenever I find a cool product, most of which I’ve purchased for my own use, I look it up on Amazon. I check the reviews and make sure that the actual seller seems legit and then add it to my “store.”  I don’t really have a real store. It’s just a convenient way of pulling together the products I’ve found and like.

Bright Ideas for Saving Energy #5: Sun Tubes

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What’s better than a sunny day? A sunny day that helps illuminate the normally dark recesses of your home!

Normally, people install skylights – basically just windows built into the roof. But skylights have several problems:

  • They’re incredibly energy inefficient. Even a good, double glazed, low-e unit is a poor insulator.
  • If they’re not facing the right direction, they don’t let any direct sunlight in during the winter and too much during the summer.
  • They’re difficult to keep clean unless the roof slope is gentle.
  • They’re prone to leakage due to ice dams created because of heat loss around the windows

A sun tube works differently than a skylight. Instead of being large windows in the roof, they’re typically smaller, about one foot to sixteen inches in diameter. Right away, this is beneficial because energy loss is directly related to the area of the opening. So a 16″ sun tube has an area about one third to one fifth of a typical skylight.

Sun tubes are built with reflectors so that they bring light into the house even as the sun moves to a variety of different locations. Usually, they are set up to reflect the Winter sun optimally but they can work well year round. I’ve installed several in my own home and really like them. One is in my office, which is on the north side of the house and never gets direct sun through the windows. However, the slope of the roof is such that for most of the year, the reflectors on the sun tube can capture sunlight and direct it into the normally gloomy room. Here’s a cheesy video demonstrating how these products work.

During the summer, sun tubes brighten rooms without heating them up like conventional skylights. If you’ve ever stood under a skylight during the summer, you know what a problem this can be. You can get a tan under some skylights! That definitely doesn’t help your air conditioning bill. Solatubes bring in the light, but due to their relatively small size and the way they work, the amount of heat that they bring into this house is very low.

Installation of sun tubes is easy. I installed one  myself, and I’m no carpenter. I just followed the directions and it went in easily. Granted, I am pretty good with a saw and don’t mind crawling around the attic. However, if you’re not up to it, there are usually “factory certified” contractors who have been trained to do the installation.

There are a variety of manufacturers of sun tubes, but my favorite is Solatube. They have residential and commercial versions are well made and easy to install. Please note – I have no business relationship with them. I’m just a happy customer!

Another nice feature of sun tubes is that they can act like light fixtures when you need electrical lighting. A simple bulb holder can be installed into the tube. Yes, it blocks a little of the light, but I’ve found this to be well worth it in the rooms where I’ve installed them.

Are they perfect? No. If you don’t like white, round plastic portholes in your ceiling, you’re out of luck. Additionally, the tubes are fairly cheap and easily damaged if you’re not careful. However, you only handle them during installation, so that’s not a big deal. They also need to be installed in rooms directly below the attic or roof because it’s a sun tube! It only directs light a few feet from the roof into the room. So they’re ideal for ranch houses or upstairs rooms but of no use on the first floor of two or three floor homes.

Other than that, I love these things. There are some rooms in my house where I almost never have to turn on the lights. If I could have, I would have installed several in my kitchen and living room.

 

Bright Ideas for Saving Energy #4 – Window Dressing

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We’ve all heard the hype – buy new windows and save 35% on your next heating bill. To put it politely, that’s a bunch of hooey. Unless your windows are old, poorly installed, leaky and missing half the glass, you are not going to save 35% on your heating bills. In fact, there are numerous studies showing that replacing windows is among the least cost effective measures for improving your home’s energy efficiency!

That said, windows are among the worst performing parts of your home when it comes to energy efficiency. Did you know that a single, 3 by 5 foot window can double the energy loss for the wall in which it’s mounted? This is why manufacturers often make such outrageous claims about energy savings. But a home loses energy through more places than its walls. It loses energy through air infiltration, walls, windows, doors, ceilings, the foundation and the slab.

Let’s compare a variety of window styles and their relative energy loss. But first, a definition:

U-value: is a measure of the energy transfer through a window. The higher the U-value, the greater the energy transfer and the worse the insulating ability of the window.

  1. Single glazed, clear glass, metal frame. U-value is above 1.0. Metal framed windows are the worst since metal conducts heat so well.
  2. Single glazed, clear glass, non-metal frame. U = 0.71 to 0.99
  3. Double glazed, clear glass, metal frame. U = 0.71 to 0.99. An old wooden, single glazed window is better than a metal framed double glazed window.
  4. Single glazed window with tight storm window. U = 0.50
  5. Double glazed, clear glass. Non-metal frame. U = 0.41 to 0.55
  6. Double glazed, low-e glass. Non-metal frame. U = 0.26 to 0.40 depending upon frame.
  7. Triple glazed, low-e glass. Non-metal frame. U = 0.15 to 0.25

Comparing U-values, we can directly compare the relative energy efficiencies of these different styles of window. For example, if you install a super insulating, triple glazed window with a U-value of 0.20, this will lose 20%-25% as much energy as an old single glazed clear glass window. That is truly substantial. In fact, when I renovated my own home, I went this route. Not because I knew the energy savings will pay off (they won’t) but I was trying to optimize my entire home’s energy efficiency and comfort.

Suppose you have a moderately old wood frame, single glazed window with a tight fitting storm window. This might have a U-value of around 0.50. If you were upgrading to a double-glazed, low-e window, which typically has a U-value of about 0.35, then the new windows would only reduce the energy loss through the window by 30%. Not bad, but not great and probably not worth the investment.

In addition, most new windows are installed poorly. I have seen many instances where a house was less comfortable after installing new windows. Why? Because the installers did not seal around the windows properly and air infiltration is much worse for energy loss than is poor insulation.

If you remove the trim from around a window, you would see something like this. The window unit would be shimmed out and nailed into place. Around the perimeter are big air gaps. Sometimes, you can even see right outdoors.

The problem is, most installers just shove fiberglass in these cracks. Fiberglass is not an air barrier. In fact, when compressed like this, it isn’t even a good insulator!

Please see my website for more detailed information on proper window installation.

For all these reasons, if your windows are in good shape and don’t seem drafty now, then I usually don’t recommend replacing them. Instead, start with some high-quality window treatments.

It’s amazing how much of a difference cellular shades or window quilts can make. At a fraction of the cost and disturbance of new windows, properly installed shades or window quilts can reduce energy loss by anywhere from 50% to 80%, making your home more comfortable and energy efficient.

Practically speaking, usually I recommend that people outfit one room with these initially to see if they yield the desired improvement. However, you really can’t go wrong with these unless you’re planning on renovating anyway and will be upgrading the windows. In that case, I suggest holding off on the window treatments until you get the new windows because often the new windows will be a different size and the treatments might not fit then ew windows.

For more detailed information, please see the links below.

Other links:

Dept. of Energy – Energy Performance ratings for Windows

Dept. of Energy – Energy Saver Tips for Windows

Efficient Windows Collaborative for more technical information on windows.

Florida Solar Energy Center – Windows

Grace-Vycor – Contractor’s Guide to Window Installation

National Fenestration Rating Council – General website

Bright Ideas for Saving Energy #3 – Light Bulbs Add Up

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The pie chart shown here should look familiar by now. We’ve already talked at length about the big slices of the pie – heating and cooling. Now it’s time to move on to lighting, shown here as 12% of the typical household energy usage.

In my experience with real homes occupied by living, breathing families, that 12% number may considerably underestimate the actual energy consumed. I’m sure that I’m biased because in my area, there are lots of large homes with modern amenities like ceilings filled with recessed lighting.

Fortunately, this is one area where homeowners can easily assess their own energy use and take actions that immediately reduce their energy use.

I have a good friend who moved into a new house. After the first few months of living there, he was about ready to move out because his monthly electric bill was averaging around $750! Fortunately, being a good engineer, he quickly noticed that this house was well lit – very well lit! There were dozens of recessed lights on each floor of this home. And with two children active at home, most of these lights were on all waking hours.

At first, he would follow the family around, grumbling as he turned off light switches. But this was a losing battle. He simply could not keep up with this round the clock. It was frustrating to him and annoying to his family. What to do?

My friend decided to start changing light bulbs. Week by week, he replaced the high usage lights with high quality compact fluorescent bulbs, each using about one quarter of the energy of the original bulbs. Pretty soon he had a box of old 90w flood lights, replaced by 23w CFLs. He was happy knowing that the house was still well lit and safe for his family but every bulb saved 67w. He also was glad not to have to replace the bulbs as often because his home has high ceilings making changing bulbs inconvenient.

A few months later, my friend came to me with a big smile on his face. “Got my latest electric bill!” he said happily. I looked at him curiously, wondering why he would be so happy about an electric bill. “It was under $250” – he beamed. “Holy cow”, I said – “you knocked $500 off your electric bill?” “Yup – it was all those damned light bulbs. I still follow them and turn off the lights, but I don’t worry about it so much any more.”

While this was an extreme example, it is a real one. Light bulbs do make a difference – the more you have, the greater the potential savings.

I’m not going to argue about the pros and cons of compact fluorescent bulbs. There are more than enough sites that discuss mercury. Instead, I’m going to show you how much energy you can save and teach you how to prioritize bulb replacement.

Step 1: Monitor Your Usage

Spend a week just paying attention to how the lights are used in your home. Which lights are left on all day? Which to you tend to turn on and off frequently? Do you have outdoor “safety” lights that stay on all night? Are there lights where the “color” is particularly important (like above a dressing table)?

I highly recommend keeping a notebook where you log each area of the house, how many bulbs there are, the wattage of those bulbs, and the number of hours they are on each day. This will make your job even easier later one.

Step 2: Prioritize Your List

Once you’ve monitored your usage and created your list, find the area with the highest usage. The highest usage is defined by the number of bulbs times the wattage of the bulbs. For example, if you have two, 100 watt  flood lights on each of the four corners of your home and those lights are on from 8pm to 8am every day, that equals 100 watts times two bulbs times four corners times 12 hour. Arithmetically written: 100 x 8 x 12  = 9600 watt hours

If you’re not familiar with spreadsheets, this is the time to learn. Plug your list into a neat spreadsheet and you’ll be able to do all these calculations really easily and then automatically sort the list by watt-hour consumption figures.

Step 3: Replace Bulbs

Assuming that you want to keep the light output from the bulbs the same, find appropriate high efficiency replacement bulbs and start replacing lights! I highly recommend checking out the EFI Store. I’ve been buying most of my energy efficient lights, fixtures, etc. from them for years and they’re amazing. Their entire business is built around helping people save energy. And, they sell quality products unlike the “big-box” stores that sell a lot of poor quality items.

A Few Considerations

  • I mentioned earlier that there are some fixtures, like above a make-up table, where you might not want to change the bulb to a CFL because color quality is important. I don’t want to sound sexist, but there’s no way around it – if you have a place where you or your spouse puts on makeup or gets dressed, don’t use CFLs. Most modern CFLs don’t have the color quality needed for this critical need.
    However, some of the LED lamps, like the CREE units sold by EFI, do provide excellent light quality.
  • LED bulbs are expensive, there’s no way around that. However, in high use areas, they can pay for themselves in a few years. They also last forever (25,000-50,000 hours) so there’s a good chance that you’ll never have to replace them.
  • If you are going to replace a light controlled by a dimmer, make sure that the replacement bulb is “dimmer compatible” or “dimmable”
  • Do not use fluorescent bulbs in areas where they’ll be on for short periods. The life of a fluorescent bulb decreases the more often it is switched on and off. So a bulb rated for 5,000 hours of life might only last 2,000 hours if flipped on and off frequently. Fluorescent bulbs are best suited for those areas where they’re left on for hours at a time, such as living space lights or outdoor safety lighting.
  • Fluorescent bulbs take a long time to warm up in cold weather, making them inappropriate for outdoor lighting that must come on quickly. For example, if you have motion sensors, this is not an appropriate place for fluorescent lights. However, this is a good place for LED lights since they come on to full brightness immediately. On the other hand, I use 13w CFL bulbs in my outside post lights that I have on a timer to come on at sunset and turn off a few hours later. They’re perfect for this application.

How Much Can You Save?

Remember the spreadsheet I had you to make earlier? Well, now’s the time to look at it more carefully.

The example of outdoor lighting I walked through showed that those outdoor bulbs use 9,600 watt-hours per day. Divide that by 1,000 to get the kilo-watt hours of use per day. In this case, 9.6. Electricity is sold by kWh, so this lets you easily compute the cost.

You’ll want to look at the rating of the bulb you buy to replace the inefficient one and do the calculations again. For example, if you replaced those outdoor lights with 23 watt CFL bulbs, the calculation is: 23 x 8 x 12 = 2,208.

Now, subtract this from the original to get the daily savings: 9,600 – 2,208 = 7,392 or 7.392 kWh per day.

Let’s calculate the yearly savings. Multiply the savings by 365: 7.392 * 365 = 2,698 kWh

And, determine your real electric cost per kWh. Do this by looking at your total electric bill and dividing the cost by the total kWh on the bill. This will include all charges for generation, transmission, taxes, etc. and will give you a rough true cost of electricity. For example, if your utility bill was $200 and you used 1,500 kWh, your cost per kWh is: $200/1,500 kWh = $0.133/kWh.

Finally, multiply these numbers together to get the yearly savings: 2,698 * $0.133 = $360.

So there’s a complete and realistic example – replacing eight 100w bulbs that are on for twelve hours a day can save $360 per year, assuming you’re paying 13 cents per kilowatt hour. This is pretty typical. Add up your savings for all your fixtures and you can see how significant the savings can be.

 

Where to buy your bulbs:

As noted throughout this post, EFI.org is the place I buy my high efficiency lights. Yes, if you click through these links, I’m part of their affiliate program, so I profit from your purchases. But that’s not why I recommend them. I recommend them because they’ve devoted their lives to helping consumers live more efficiently. They’re not some Johnny-come-lately store that’s just doing it because it’s the latest trend. Check out their blog and “about” pages and you’ll see. They deserve our support.