Home Insulation Is The Best Way
To Save Energy

MANY EXPERTS SAY that home insulation is the very best way to save energy. There is an awful lot of information out there — maybe too much. Let's try to simplify it by looking at the questions I was asking myself when I embarked on this home insulation project, as well as the answers I found.

NOTE: Because I live in a cold North American climate, the information in these pages is based on that fact; it may have to be adapted to your own circumstances if they are different from mine.

WHY INSULATE?

Apart from the moral issues...

• Concern over the effects of global warming and what to do about it;
• The desire for a smaller personal ecological footprint and a reduced carbon footprint;
• Belief in a system or way of life such as permaculture or voluntary simplicity;

...there are the practical issues:

The immense satisfaction of knowing that thanks to the right kind of home insulation in the right place, your home is as energy efficient as you can afford to make it; The plain, unadulterated comfort of a living space that is warm and draft-free in winter and naturally cool in summer;

• The financial rewards that keep coming month after month, in the form of a low power bill;
• In my case, the desire to achieve -- and even surpass -- the energy efficiency goals outlined in my energy audit, and to qualify for the grants and incentives being offered to homeowners by the different levels of government for home insulation.
  

WHICH PARTS OF THE HOUSE NEED INSULATION?

Some of the areas requiring insulation

Here's an alphabetical list of locations where home insulation could be applied:

Attic Attic door or hatch Basement walls Ceilings Concrete slab Crawl space Doors Ducts Exterior Floors

Foundations Furnace Garage Garage door Heating ducts Roof Siding Walls Water Heater Windows

The good news is that many of these are DIY -- or do-it-yourself -- home insulation projects, and most of them will be covered in these pages.

EVERY SITUATION IS UNIQUE

First, Set Your Goals

Since the very inception of this project, I knew what my goal was, since that goal was the very raison d'être of the project:

1. To reduce my housing expenses enough that I would be able to live out my old age on my modest government pension, if necessary;
2. To accomplish this without abandoning the principles of permaculture that had played such a huge role in my life in the last decade and a half;
3. All this within my budget, circumstances, and abilities.

As I was already in my sixties, there was a definite sense of urgency in this.

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 gutted house is ready for home insulation

After a full year of studying my house, trying to figure out the unfamiliar and capricious Maritimes climate, researching every possible kind of home insulation,, consulting with suppliers and experts, getting an energy audit, and finding out what was available to me locally (remember: I live in a small province, in a tiny remote village - but also I believe strongly in encouraging the local economy), I concluded that the following areas had to be insulated:

A. Main building (including bathroom & stairwell):

• Two outer walls
• Stairwell inner wall
• Main ceiling
• Stairwell ceiling
• Attic hatch/ladder unit
  

B. Sunroom-office addition:

• Three outer walls
• Cathedral ceiling
• Floor
  

C. Kitchen-dinette addition:

• Three outer walls
• Cathedral ceiling

D. Crawl space (under kitchen-dinette):

• Three outer walls
• Outer sill plates

E. Main building basement:

• Sill plate on all four sides (inner walls as well as outer walls)
• Laundry room walls
• Stairwell wall

We decided NOT to insulate the following areas for the moment, but rather to observe during an entire yearly cycle and then proceed according to the conclusions that will result from our observation:

1. Attic: nothing was added to the attic this first year. It was decided to go through one winter in order to determine — by monitoring the temperature upstairs — just how effective the low-density main floor ceiling insulation/vapor barrier combination would be.

(Note: the attic is actually the former second storey of the house, which has been sealed off. There is already some insulation in the ceilings (under the roof) and the rooms are finished and the floors carpeted.)

Therefore, if you need information about attic insulation now, Green-Energy-Efficient-Homes.com is an excellent site that covers attic ceiling insulation.

2. Basement walls: there are cracks in the foundation which have been allowing for some water infiltrations under extreme rainfall conditions (which are getting more frequent, due to climate change).

Until the ground has been re-graded, window wells, eaves troughs and drain tile installed -- all of which should take care of the moisture problem -- there is danger of introducing mold problems if we cover up those walls.

If the planned measures don't cure the problem, and because my budget doesn't allow for extensive foundation work, the basement will remain as it is -- and a dehumidifier used in summer.

3. Basement ceiling: I have looked, I have asked, but I can't get a consensus on whether basement ceilings should be insulated or not. Therefore, I am reserving that decision until I get more information. Cold floors are not nice, but I like Oriental rugs and have quite a collection!

4. Crawl space ceiling: some of the above arguments apply, except that the crawl space walls are insulated and the dirt floor is dry and it will have a good vapor barrier. I will have to monitor the temperature closely because of the water pipes going through that area, which is to the north and has its walls exposed on three sides -- at least for the moment.

KEY: A Main Building; B Sunroom-Office; C Kitchen-Dinette;
(there is a crawl space under C, a full basement under A and D, and a concrete slab under B)

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 home 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.

The best way to find out if you have air leaks and where they're located is to perform an energy audit of the house.

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):

Batt insulation Blown in insulation Cellulose insulation Cotton insulation Denim insulation (blue jeans) Fiberglass insulation Foil insulation Foam board insulation Loose fill insulation Mineral wool Polystyrene insulation

Polyurethane insulation Radiant barrier Reflective insulation Rigid foam insulation Rock wool insulation Soy-based insulation Spray foam insulation Styrofoam insulation Urethane foam insulation Water heater insulation Window insulation film Wool insulation

No wonder there's confusion out there! But don't go away: many of these -- all the major ones in fact -- will be covered in these pages.

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, as in the photo on the left -- while newer houses have panelled walls, similar to the photo on the right.

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.

Then, depending on whether your home insulation will be a DIY project or not, it's just a matter of talking to the store, contractor or supplier to get an estimate of the quantity and price.

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 to use, 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)

1. Main building - walls and ceilings: low-density (1/2-lb.) Home Foam brand spray foam, between all studs and joists (four good inches), sprayed full and trimmed.


2. Walls of the two additions (sunroom/office and kitchen/dinette): low-density (1/2-lb.) Home Foam brand spray foam.


3. Cathedral ceilings (sunroom/office and kitchen/dinette): four inches of high-density (2-lb.) BASF Walltite brand spray foam (also known as "blue foam"). (PDF file)


4. Kitchen-dinette exterior walls and cathedral ceiling will benefit from additional insulation via a layer of reflective insulation/vapor barrier of the "foil-bubble-vinyl" type. This was judged necessary because of the windy northern exposure of that part of the house.


5. Crawl space walls and sill plates: high-density Walltite spray foam.


6. Main building sill plates: the same high-density Walltite spray foam.


7. Sunroom/office floor (where the foundation is a concrete slab): 1-1/2 inches of rigid foam insulation installed (a) over a ledge which was nailed near the lower part of the 6-inch floor joists, but
   (b) six inches away from the three outer edges. Those six inches - which encompassed the sill plate - were then filled with high-density Walltite spray foam. As well, the rigid foam was topped with two inches of high-density Walltite spray foam.


8. Basement laundry room walls: fiberglass batts reused from the original ceiling insulation (R-00).


9. New stairwell walls: purchased fiberglass batts (R-00)


10. Attic: nothing was added to the attic this first year. It was decided to go through one winter in order to determine - by monitoring the attic temperature - how effective the low-density ceiling insulation/vapor barrier combination would be. (Note: the attic is actually the former second storey of the house, which has been sealed off.)


11. Attic hatch/ladder unit: This has yet to be installed at this writing. However, an effective foam and/or rubber gasket is planned, as well as a light "mattress" that will sit on top of the whole contraption.

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:

• Fiberglass batts or loose fill: 3.0 to 3.7 per inch;
• Cellulose fibre (loose): 3.0 to 3.7 per inch;
• Rigid board: 3.6 to 6 per inch (depending on type);
• Low-density spray foam: 3.6 per inch;
• High-density spray foam: 5.8 to 6.8 per inch.

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 INSULATION 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:

• $2.50 to $3.00 per square foot for the basements (BASF Walltite 2-lb foam);
• $6.00 per square foot for the cathedral ceilings (BASF Walltite 2-lb foam); and
• $3.00 per square foot for the walls (1/2-lb low density Home Foam).

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 at the time), 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 for home 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.

For more information about Monsanto, the Organic Consumers Association has a very informative page on its website. Greenpeace International has 20 pages of results under "Monsanto".

DOLLAR-BY-DOLLAR ACCOUNT

So far, the only home 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 LINE

As stated earlier, my home insulation project had several goals, including conserving energy and saving money.

Now that I've lived in my little house over two heating seasons, I'm pleased to report that my heating bills are very affordable.

STEP-BY-STEP PHOTOS

As with all other aspects of this project, I am documenting this home insulation process step-by-step. You may want to visit these other pages as well where you will find a great number of photos:

• Spray Foam Insulation
• Foil Insulation
• Vapor Barrier
• Water Heater Insulation
• Attic Door Insulation

RESOURCES

The Canada Mortgage and Housing Corporation (CMHC) website has a very useful Fact Sheet on Insulation in their "About Your House" Series.

The Old House Web has an excellent section called Insulation: The Facts.

There is an abundance of information about home insulation online; by all means use the web for your research, but be sure that the advice you get is from an independent source.

GREEN NOTES

The pink batt insulation in the following picture is part of what we salvaged during the deconstruction phase. It was perfect for this basement laundry room wall.

Fiberglass insulation batts salvaged from other parts of the house
are being reused in the basement laundry room walls.

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