CRS Referred Products
Insulation
Insulation is not as stylish as new windows. It's not as dramatic as a new
heating or cooling system, or even as interesting as a new water heater. Yet
it's the single most important factor in keeping you comfortable and making your
home energy-efficient. Good insulation means lower energy bills, greater
comfort, peace and quiet, and often, a better value to buyers if you're selling
your home. Of course you should caulk around windows and doors, cover electrical
outlets on outside walls, close the drapes at night in the winter and during the
day when the weather is hot. But if you don't have adequate insulation, you may
still be uncomfortable . . . and will certainly be spending too much money on
heating and cooling. Insulation is one of the best investments you can make.
How insulation works
Air is not a good conductor of heat. Insulation materials have millions of
tiny air spaces that literally baffle heat; the smaller the air spaces, and the
more of them, the better the insulation. Insulation is rated by R-value, its
resistance to heat flow. The higher the R-value, the more effective the
insulation.
Choices
The best insulation material: Is inexpensive and easy to install Has a high
R-value Has no adverse health or environmental impacts Is fireproof or
fire-resistant Won't shrink or settle after installation The most common form of
insulation is fiberglass or rock wool batts. Batts are sized to fit standard
spacing between wall studs, rafters, and floor joists, and can be used in
allareas of the house. They are easy to install during new construction, under
wood floors in existing houses, or when walls are opened during remodeling.
Loose fill mineral fiber or loose fill cellulose insulation is usually blown
into attics and existing wall cavities. Loose fill cellulose is made from
recycled newsprint, so it is particularly environment- friendly. Another kind of
blown-in insulation is the Blow in Blanket System ™ (BIBS), which consists of
chopped fiberglass mixed with binders and blown behind netting in open walls.
This patented system is usually used in new construction. Installing any
blown-in insulation is a job for a professional. Enliance can refer you to
qualified contractors in your area.
Insulation R-values
Inches of insulation R-value
- 1 to 3 inches R-3 to R-10
- 4 to 6 inches R-11 to R-19
- 7 to 11 inches R-20 to R-30
- 12 or more inches R-31+
Rigid foam board is used to insulate foundations and slabs and to sheathe
walls or roofs. Foam board insulation with a high R-value can be useful when
space is limited. It must be protected from sunlight.
Fire safety
Even if the insulation you choose is fireproof, there are some precautions
you should take when you install it: "Knob and tube" wiring and fuses found in
many homes built before 1950 should be inspected by an experienced, licensed
electrician before you install insulation. Metallic vapor barriers should never
contact these wires. Insulation materials must stay clear of metal chimneys and
other heat sources. Check your local building code for the specifications and
suitable fireproof barriers (called baffles). Never install blown-in wall
insulation in a wall cavity that has a recessed electric wall heater. Be sure to
keep insulation away from heat-producing light fixtures and fan motors.
Insulate, Insulate, Insulate!
Real estate agents will tell you that the most important factors in selling
your home are location, location, location. Location matters for insulation,
too. Attics, floors and walls are the most important places to insulate, but
there are others:
Heating ducts located in unheated spaces
You may be losing a third of your heating system's output through
uninsulated, leaky ducts. Secure loose duct joints with sheet metal screws. Seal
leaky joints with latex duct mastic or foil-backed, butyl rubber tape (never use
duct tape—it fails in a short time), then insulate ducts in unheated areas to
R-8. WATER PIPES Insulate water pipes that run through unheated areas (for
example, crawl spaces) or outside walls to a minimum of R-3 with foam pipe
insulation. You'll not only save energy, but keep pipes from freezing in cold
weather.
R-Value recommendations location
Recommended R-value
- Heating ducts in unheated spaces R-8
- Unheated attic above heated rooms R-38
- Sloped or cathedral ceilings R-30-38
Under floor
- 2" x 6" joists R-19
- 2" x 8" joists R-25
- 2" x 10" or larger joists R-30
- Water pipes R-3
- Exterior walls R-11 to 13 for older homes
- Heated basement R-11-19
Insulation R-values for commonly used materials
- Fiberglass batt, standard density R-2.9 to R-3.7 per inch
- Fiberglass batt, high density R-3.5 to R-4.3 per inch
- Blown mineral fiber R-2.2 to R-2.9 per inch
- Blown cellulose R-3.1 to R-3.7 per inch
- Blow in Blanket System ™ (BIBS) R-3.8 per inch
- Rigid foam board R-3.7 to R-8 per inch
R-values per inch of insulation materials vary with density. Densities vary
among manufacturers and products. Read product literature and estimates from
insulation contractors carefully. Divide the R-value by insulation thickness to
get R-value per inch. Insulation costs also may be compared on the basis of cost
per "R" per square foot for the insulation material or the installed cost
including labor.
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