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Checking your home's insulating system is one of the fastest
and most cost-efficient ways to use a whole-house approach to
reduce energy waste and maximize your energy dollars. A good
insulating system includes a combination of products and
construction techniques that provide a home with thermal
performance, protect it against air infiltration, and control
moisture. You can increase the comfort of your home while
reducing your heating and cooling needs by up to 30% by
investing just a few hundred dollars in proper insulation and
weatherization products.
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Where to Insulate
Adding insulation in the areas shown here may
be the best way to improve your home's energy
efficiency.
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Insulation
Should I
insulate my home? First, check the insulation in your
attic, ceilings, exterior and basement walls, floors, and crawl
spaces to see if it meets the levels recommended for your area.
Insulation is measured in R-values - the higher the
R-value, the better your walls and roofs will resist the
transfer of heat. The U.S. Department of Energy (DOE)
recommends ranges of R-values based on local heating and
cooling costs and climate conditions in different areas of the
nation. For a more accurate and simpler method of determining
your insulation needs, try the
Interactive ZIP Code Insulation Program, which uses your
zip code and some information about your house to tell you
where to add insulation. The program was developed by the
Energy Division of the Oak Ridge National Laboratory. State
and local codes in some parts of the country may require
lower R-values than the DOE recommendations, which are based on
cost-effectiveness.
Although insulation can be made from a variety of materials,
it usually comes in four types-batts, rolls, loose-fill, and
rigid foam boards. Each type is made to fit in a different part
of your house. Batts are made to fit between the studs in your
walls or between the joists of your ceilings or floors. Batts
are usually made of fiber glass or rock wool. Fiber glass is
manufactured from sand and recycled glass, and rock wool is
made from basaltic rock and recycled material from steel mill
wastes. Rolls or blankets are also usually made of fiber glass
and can be laid over the floor in the attic. Loose-fill
insulation, usually made of fiber glass, rock wool or
cellulose, is blown into the attic or walls. Cellulose is
usually made from recycled newsprint treated with
fire-retardant chemicals.
Rigid foam boards are made of polyisocyanurate, extruded
polystyrene (XPS), expanded polystyrene (EPS or beadboard), or
other materials. These boards are lightweight, provide
structural support, and generally have an R-value of 4 to 7
per inch. Rigid board insulation is made to be used in
confined spaces such as exterior walls, basements, foundation
and stem walls, concrete slabs, and cathedral ceilings.
Insulation Tips
- Consider factors such as your climate, building design,
and budget when selecting insulation R-value for your
home.
- Use higher density insulation, such as rigid foam boards,
in cathedral ceilings and on exterior walls.
- Ventilation plays a large role in providing moisture
control and reducing summer cooling bills. Attic vents
can be installed along the entire ceiling cavity to help
ensure proper airflow from the soffit to the attic,
helping to make a home more comfortable and energy
efficient.
- Recessed light fixtures can be a major source of heat
loss, but you need to be careful how close you place
insulation next to a fixture unless it is marked.
"I.C." - designed for direct insulation contact. Check
your local building codes for recommendations.
- As specified on the product packaging, follow the
product instructions on installation and wear the proper
protective gear when installing insulation.
The easiest and most cost-effective way to insulate your home
is to add insulation in the attic. To find out if you have
enough attic insulation, measure the thickness of insulation.
If there is less than R-22 (7 inches of fiber glass or rock
wool or 6 inches of cellulose) you could probably benefit by
adding more. Most U.S. homes should have between R-22 and
R-49 insulation in the attic.
If your attic has ample insulation and your home still feels
drafty and cold in the winter or too warm in the summer,
chances are you need to add insulation to the exterior walls
as well. This is a more expensive measure that usually
requires a contractor, but it may be worth the cost if you live
in a very hot or cold climate.
You may also need to add insulation to your crawl space. Either
the walls or the floor above the crawl space should be
insulated.
New Construction
For new construction or home additions, R-11 to R-28 insulation
for exterior walls is recommended for most of the country. To
meet this recommendation, most homes and additions constructed
with 2 x 4 walls require a combination of wall cavity
insulation, such as batts, and insulating sheathing, or rigid
foam boards. If you live in an area with an insulation
recommendation that is greater than R-20, you may want to
consider building with 2" x 6" framing instead of 2" x 4"
framing to allow room for thicker wall cavity insulation - R-19
to R-21.
Visit the Insulation
Contractors Association of America's web site for product
information and more on hiring insulation contractors.
Weatherization
Warm air leaking into your home during the summer and out of
your home during the winter can waste a substantial portion of
your energy dollars. One of the quickest dollar-saving tasks
you can do is caulk, seal, and weatherstrip all seams, cracks,
and openings to the outside. You can save 10% or more on your
energy bill by reducing the air leaks in your home.
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How Does the
Air Escape?
Air infiltrates into your through every hole,
nook and cranny. About one third of this air
infiltrates through openings in your ceilings, walls,
and floors.
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Weatherization Tips
- First, test your home for air tightness. On a windy
day, hold a lit incense stick next to your windows, doors,
electrical boxes, plumbing fixtures, electrical outlets,
ceiling fixtures, attic hatches, and other locations where
there is a possible air path to the outside. If the smoke
stream travels horizontally, you have located an air leak
that may need caulking, sealing, or weatherstripping.
- Caulk and weatherstrip doors and windows that leak air.
- Caulk and seal air leaks where plumbing, ducting, or
electrical wiring penetrates through exterior walls, floors,
ceilings, and soffits over cabinets.
- Install rubber gaskets behind outlet and switch plates on
exterior walls.
- Look for dirty spots in your insulation, which often
indicate holes where air leaks into and out of your house.
You can seal the holes by stapling sheets of plastic over
the holes and caulking the edges of the plastic.
- Install storm windows over single-pane windows or replace
them with double-pane windows. Storm windows as much as
double the R-value of single-pane windows and they can help
reduce drafts, water condensation, and frost formation. As
a less costly and less permanent alternative, you can use
a heavy-duty, clear plastic sheet on a frame or tape clear
plastic film to the inside of your window frames during the
cold winter months. Remember, the plastic must be sealed
tightly to the frame to help reduce infiltration.
- When the fireplace is not in use, keep the flue damper
tightly closed. A chimney is designed specifically for
smoke to escape, so until you close it, warm air escapes -
24 hours a day!
- For new construction, reduce exterior wall leaks by either
installing house wrap, taping the joints of exterior
sheathing, or comprehensively caulking and sealing the
exterior walls.
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