![]() |
|||||||||
![]() |
Here's an alphabetical list of locations where home insulation could be applied:
The good news is that many of these are DIY -- or do-it-yourself -- insulation projects!
EVERY SITUATION IS UNIQUEFirst, Set Your GoalsSince the very inception of this project, I knew what my goal was, since that goal was the very raison d'être of the project:
Ready, Set, Go! From the start, it was imperative that the house be entirely paid for. In trying to foresee the future, I realized that if I ever had to live on my retirement pension alone, my income would not be sufficient to cover a mortgage. So, I bought a house for $10,000. I had enough savings for the modifications (I hoped!). The house had to be very inexpensive because in order to apply the quantity and quality of home insulation that was necessary in order to seal it well against the elements, every wall and ceiling had to be stripped completely. Because of my commitment to make this as green a project as I could, instead of demolishing, wherever possible we used the deconstruction method which is described in my deconstruction page.
The house, with gutting completed, ready for home insulation
KEY: A Main Building; B Sunroom-Office; C Kitchen-Dinette;
DON'T FORGET TO SEAL AIR LEAKS!Spending all that money on home insulation and not doing anything about air leaks is like having an umbrella with holes in it!This is because insulation does not reduce air movement through cracks between building parts. (Spray foam, particularly the high-density type, is somewhat efficient at this, however.) For example, controlling air movement within a wall cavity will not stop air that leaks between the foundation and the sill plate or between the wall joists and a window frame. The following illustration shows just some of the places where air can unknowingly enter the house, and greatly diminish your return on your home insulation investment.
You can do this yourself (PDF file) or hire a specialist. Once you know where your house is leaking, get a hold of a caulking gun and some inexpensive caulking, and caulk, caulk, caulk. Of course, if you're doing some major remodeling, a vapor barrier is the way to go.
WHAT ARE THE DIFFERENT TYPES OF HOME INSULATION?Again, let's look at it alphabetically (some of these designations are synonyms):
No wonder there's confusion out there! WHY SO MANY DIFFERENT TYPES? The reason that there are so many types is that not every type is appropriate for every situation. For example, the main factor in my decision to use spray foam insulation in my house was the fact that most of the walls and ceilings in old houses like mine are made up of wood planks. (Newer houses have panelled walls, similar to the photo, below.)
An old wall and a modern wall
As you can see, old planks have spaces between them. They also have cracks, knots and warps. It's easy to see why conventional batt insulation (be it fiberglass, cotton, or whatever) cannot do a thorough job of keeping the cold out of that kind of wall. Rigid foam insulation is even worse. It's impossible to obtain a bond between it and an old wall of planks. Spray foam, on the other hand, penetrates the cracks, gaps and knots, and seals them. The denser the foam, the better the seal. Yet I have not read about this anywhere. It was a friend who warned be about it. Merci, Louise! Check the Resources at the bottom of this page for details about the different types of home insulation and other relevant information.
HOW MUCH HOME INSULATION IS ENOUGH?You have to start by determining the correct R-values for your geographical area and for each part of the house.There are lot of calculators online, like the ones on this site. The calculations are based on US zip codes, but there's probably a similar calculator for your country. Home improvement stores and home insulation contractors have this information. WHAT ABOUT DIY SPRAY FOAM INSULATION?Speaking of DIY, do NOT be tempted to try those do-it-yourself spray foam kits! Spray foam is NOT a product for amateurs. Spray foam contractors working for responsible companies have received serious training from the product manufacturer. (The small cans for filling gaps are okay, though.)WHEN "WHAT" MEETS "WHERE"...Having decided what to use and where to apply it, at long last, in October, we began to insulate. This is what we did: (Click here for step-by-step photos)
HOW DOES HOME INSULATION WORK?Heat flows naturally from a warmer to a cooler space. In winter, the heat moves directly from all heated living spaces to the outdoors and to adjacent unheated attics, garages, and basements - wherever there is a difference in temperature.During the summer, heat moves from outdoors to the house interior. To maintain comfort, the heat lost in winter must be replaced by your heating system and if the heat gained in summer is excessive, you may need air conditioning. Insulating ceilings, walls, and floors decreases the heating or cooling needed by providing an effective resistance to the flow of heat. Batts, blankets, loose fill, and low-density foams all work by limiting air movement. The still air is an effective insulator because it eliminates convection and has low conduction. Some foams are filled with special gases that provide additional resistance to heat flow. Reflective (or radiant) insulation – also known as "radiant barrier" – works by reducing the amount of energy that travels in the form of radiation. It reflects some of the heat back where it came from. Check out this link for a good explanation of the principle of reflectivity. (PDF file) That's the type we used in the kitchen-dinette. Yo can see the step-by-step here. An insulation's resistance to heat flow is measured or rated in terms of its thermal resistance, or R-value.
WHAT ON EARTH IS R-VALUE?Home insulation is rated in terms of thermal resistance, called R-value, which indicates the resistance to heat flow. The higher the R-value, the greater the insulating effectiveness. The R-value of thermal insulation depends on the type of material, its thickness, and its density. In calculating the R-value of a multi-layered installation, the R-values of the individual layers are added.However, the way the insulation is installed plays a large role in its effectiveness. Compressing the insulation, leaving air spaces around it and/or allowing air movement within it all reduce the R-value of the insulation. Some typical R-values:
There's a detailed list at the CMHC website.
WHICH R-VALUE GOES WHERE?Following my house's energy audit, the Energy Efficiency Evaluation Report issued by my advisor recommended R-24 for the basement and crawlspace walls, R-10 for the exterior walls and R-50 for the attic.As mentioned earlier, we did not insulate the basement walls, nor the attic, but our exterior walls, with 4 inches of low-density foam @ approximately R-3 per inch, surpass the goal. For the crawlspace walls, we are short by a wide margin (approximately R-10 against a goal of R-24), but the cost of the additional two or three inches was prohibitive at this time. In addition, that wall, which is exposed at present, will end up buried once the land has been regraded -- and earth is an excellent insulator. You can use this U.S. Department of Energy's Calculator to determine the R-values recommended for each area of your house. While you're there, check out their Insulation Fact Sheet. The Canada Mortgage and Housing Corporation has an excellent section on home insulation too. Both sites offer more information than this little website can possibly supply.
HOW MUCH DOES IT COST?My house is a mere 925 square feet, and yet my bill for the spray foam part was over $8,300.There are and will be other types of insulation used in my house, as well as vapor barriers -- making the insulating and air sealing of the house the most expensive part of my whole project. According to the contractor's estimate, the above cost breaks down as follows:
The differences are due to the thickness of the application (from 2 to 4 inches, depending on the area). I do not know how much other types of home insulation would have cost, as I was determined that spray foam was the only type that would justify going to such lengths and expense -- gutting the house was a major project in itself and could only be feasible if it was fully taken advantage of. Given my age (67), it may seem foolish to invest so much money in this way. It's probable that I will never recover my investment. On the other hand -- and I've mentioned this before -- what if I find myself having to live on just my retirement pension some day? I don't want to risk seeing the major part of my income go towards heating bills -- ever. Every part of that house is being planned for my old age: the single storey, the level entrance, the wide doorways -- and of course the energy efficiency. Peace of mind has its price. WHAT IS THE PAYBACK PERIOD OF HOME INSULATION?Example: How many years will it take to recover the cost of installing additional insulation?Let's say you're planning to increase the level of insulation in your attic -- from R-19 (6-inch fiberglass batts with moisture barrier on the warm side) -- to R-30 by adding R-11 (3.5 inches of unfaced fiberglass insulation batts). Your furnace is gas with an AFUE (efficiency rating) of 0.88. Cost of gas is $0.87/therm. Well, according to the formula explained on this U.S. Department of Energy page, "Estimating the Payback Period of Additional Insulation", it will take you 5.62 years. WHAT? NO SOY?Naturally, this being a green project, I investigated the not-so-new soy-based foam insulation.There is only one type of soy-based foam insulation, and it's the high density, 2-lb kind. That means it's expensive. I found a contractor who works with it and got an estimate. At $17,809, it was more than double the other estimate. To be fair, it did include some additional square footage, namely the two outside basement walls. And of course, I would be getting better R-values, perhaps more than I really needed. However, at my age, I just could not justify the extra investment. I would have to SAVE an additional $8,000 in my lifetime -- say, 20 years -- or $400 a year. Not just a $400 a year saving, but an additional $400 over what I would save with the mix of spray foam insulation types that I was planning on having. It would be possible, I suppose, but I didn't think it was worth taking the chance. Some of you will be thinking, "What about the environmental factor? Isn't spraying your house with soy (and recycled plastic bottles, another ingredient) like buying organic food: you pay more for your ethics?" In a word, No. After I got this estimate, I decided to ask questions. I wrote one of the soy-based foam manufacturers and asked what was the percentage of soy in the foam. I got this reply: You obviously cannot just mix soya oil and recycled plastics and get foam. All foams are two-component foams and there are many other parts to the liquids. What we have done is made the foam as "green" as possible. For both soya oil and recycled plastics it is 19-20% total weight by volume. Assuming that it's half and half, the foam would only be 10% soya oil. Recycling plastic bottles sounds good, but personally I'd rather see them not being used in the first place, and I do not use them myself. I don't even want them in my walls. In addition, the extraction of oil from soya beans and the recycling of plastics are both energy-intensive processes. Enter Monsanto And then, there's the little matter of Monsanto controlling practically all the soy crops in the world. Not just the beans, but the seeds as well. Thanks to Monsanto, most of the soy being grown in the world comes from genetically-modified seeds and Monsanto holds the patent. Monsanto is one of the worst companies in the world. If I used soy-based insulation, I would end up knowingly putting money in its pockets. The above video is part of a film by an independent French director, Marie-Monique Robin, "The World According To Monsanto". You can get the story and the background by visiting the Greenpeace website. To see other parts of the film, click on the link under the video. For more information about Monsanto, the Organic Consumers Association has a very informative page on its website.
DOLLAR-BY-DOLLAR ACCOUNTSo far, the only insulation expense that I have posted to the expense report is the $8,300 invoice from the spray foam insulation contractor. But there will be others, and I will upload them regularly so that by the time the renovation is over, you and I will know exactly how much I have spent on my home insulation.The links to the expense reports are at the bottom of my Dollar-by-dollar page. THE OTHER BOTTOM LINEAs stated earlier, home my insulation project had several goals, including conserving energy and saving money.I won't know about the former until the follow-up door blower test and I can't measure the latter until I have gone through an entire heating season and that won't be until next year, because as I write this it's January 2009 and the house is far from ready to move into. The door blower test results with the house's new energy efficiency rating will be posted here in the spring of 2009 -- so if you're interested, do come back then. And as soon as I move into the house, I will start posting my energy bills regularly, in the same way as I am now uploading the dollar-by-dollar accounting of the project. STEP-BY-STEP PHOTOSTo see all the photos of my home insulation process, visit these step-by-step pages:
|
||||||||