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Insulation and Weatherization |
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Q. What does the term "R-value" mean?
A. R-value is a measure of how well a material resists the
passage of heat. The higher the R-value, the more effective
insulation is in keeping the home warm in winter and cool in
summer. Insulation should always be judged by R-value rather
than inches, as different insulation materials have different
R-values per inch of thickness.
Q. How much insulation should I have in my attic?
A. Attics should be insulated to R-40 whenever possible.
Q. If I install more insulation in my attic, what type should
I use?
A. Most homeowners find it easiest to use batt insulation.
If possible, install the new insulation perpendicular to the
attic floor joists to reduce heat loss through the joists. Loose
fiberglass or cellulose can also be used, by pouring it and
leveling it with a board or other implement.
Q. How much insulation should I have under my floor?
A. Floors over unheated crawlspaces or basements should be
insulated with no less than R-20, while floors over open air
(such as overhangs) should be insulated to R-40 if possible. If
your home has a basement containing your heating system or other
sources of heat, you should insulate the basement walls to R-12,
rather than insulating the floor above.
Q. Is it better to insulate the attic floor, the roof, or
both?
A. Unless you are finishing the attic for living space, you
should insulate the attic floor to contain the heat within the
living space.
Q. Is it a good idea to add additional insulation to my
walls, and how is this done?
A. If your walls currently have no insulation, insulation
can be blown into the cavities through holes drilled through the
exterior of the home. This should only be done by a reputable,
qualified contractor.
Q. Can I compress 15cm (6 inch) R-20 batts to fit into a 2"x
4" cavity, and will it be more effective than 9cm (3 1/2 inch)
batts?
A. While insulation batts are easily compressed, the R-value
will be significantly reduced - it is best to use the correct
thickness and not compress the insulation. You should also avoid
storing heavy materials on top of attic insulation for the same
reason.
Q. I've always heard that "heat rises". Why do I need to
insulate my floors?
A. Actually, heat moves from warm to cold. If your home is
built over a crawlspace or unheated basement, you can lose a lot
of heat downward through the floors. Insulation will help reduce
that loss and also make your floors feel warmer in the winter.
Q. If the walls and ceiling of my home are well insulated, do
I really need to insulate my basement?
A. Because basements are within the house's envelope, the
walls should be insulated.
Q. What is a "vapour barrier" and how important is it?
A. A vapour barrier, also known as a vapour retarder, is a
material that resists the passage of water vapour. A properly
installed vapour barrier (facing the warm-in-winter side) can
minimize the chance of water vapour condensing inside your wall
insulation, which not only reduces the insulation's
effectiveness but can also cause damage to your home.
Q. I've heard that you can make a home "too tight" - should I
be concerned about this?
A. No house can be too tight, but it certainly can be
under-ventilated. Leakiness is not ventilation. A lack of
controlled ventilation can lead to a build-up of moisture,
odours, bacteria, fungi and combustion gases such as carbon
monoxide, carbon dioxide and other pollutants. Ventilation
prevents excessive build-up of these and other indoor
contaminants that can affect your health and comfort and damage
buildings.
Q. What is the best type of insulation to use in my attic?
A. Either loose fill (typically fiberglass or cellulose) or
batt insulation (usually fiberglass) will work well. Batts are
easier to install yourself, while many contractors find loose
fill easier and less expensive to install.
Q. Is it better to caulk my windows and doors on the inside
or the outside?
A. Any large gaps on the outside should be weatherproofed to
keep rain out, but the inside is generally the best place to
caulk to keep the heated air inside, along with any water vapor
that could condense in a cold wall cavity.
Q. Can I insulate over recessed lighting fixtures (pot
lights)?
A. Only if the fixtures are designed to be covered with
insulation. Otherwise you should maintain 7.5cm (3 inches) of
clearance around the fixtures and leave the top of the fixture
uncovered to avoid potentially hazardous heat buildup within the
fixture. The only acceptable way to insulate the older pot
lights is to build a sealed box over them and then cover the
sides and top of the box with insulation. Minimum box dimensions
shall be either 35cm wide x 1.2m long x 30cm high (14" W x 48" L
x 12" H), or 53cm wide x 74cm long x 30cm high (21" W x 29" L x
12" H).
Q. What is a "thermopane" window, and how does it work?
A. A "thermopane" or double-paned window has two panes of
glass, separated by a trapped air space. The trapped air acts as
an insulator, reducing heat loss through the glass.
Q. My home has single-paned windows - would it be better to
replace them with double-paned windows or to add storm windows?
A. Both double-paned or thermal windows and storm windows
work by creating an insulating air space between the panes of
glass. If your existing windows are in good shape, storm windows
will usually be more cost-effective. If your existing windows
are damaged or if you are replacing them for aesthetic reasons,
you should install double-paned, energy efficient windows.
Q. Why does moisture form on the inside of my windows in
winter, and how can I minimize the amount of moisture?
A. Condensation will occur whenever warm air hits a cold
surface because warm air can hold more water vapour than cold
air. If you have single-paned windows, adding storm windows will
keep the inner pane of glass warmer and reduce the amount of
condensation. Monitoring your indoor humidity and keeping it in
the range of 40 - 50% (even less in very cold weather) will also
help.
Q. What are "Low-E" windows?
A. "Low-E" windows incorporate a microscopically thin layer
of a metal oxide which reduces the amount of heat transferred
through the glass without reducing the amount of light.
Q. I'm considering having vinyl siding installed on my
home. Will this reduce my heating and cooling costs?
A. Vinyl siding is typically installed over a thin layer of
foam insulation material. Although this material has some
insulating value, it is minimal. You should be skeptical of any
claims of substantial energy savings. The main benefits of vinyl
siding are enhanced appearance, reduced maintenance and
potentially increased resale value.
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