"A big revelation about insulation came when a consultant first informed me that I can use more than one type of insulation in the same house and invited me to 'think outside the batt'!" --editor


Certainly, a well insulated house is the goal, regardless of the material you use. But fortunately it is getting pretty easy to add some environmental considerations to that goal. The chart below can help you learn about the various insulation materials for new and remodeled residential construction.

Compare insulation products side by side on environmental and practical characteristics, or you can also see how our Professional Panel responds to our questions about insulation.

Every material has a specific ability to resist heat traveling through it; this is its R-value. Higher R value = better insulation. Insulation can range from plain fiberglass batts (a funny word for roll) (R-2.2) to high-tech aerogel based products (R-50). For the residential market, however, there are essentially three forms of insulation: flexible sheets, rigid boards, and spray or blow-in products.

(Check out The recommended R-values for areas you want to insulate, offered by The US Department of Energy, and compare them to your local codes.)

Form Insulation Materials Where Applicable Installation Method(s) Advantages
Blanket: batts and rolls Fiberglass
Mineral (rock or slag) wool
Plastic fibers
Natural fibers  		Unfinished walls, including foundation walls, and floors and ceilings. Fitted between studs, joists, and beams. Do-it-yourself.
Suited for standard stud and joist spacing, which is relatively free from obstructions.
Foam board or rigid foam Polystyrene
Polyisocyanurate or polyiso
Polyurethane 		Unfinished walls, including foundation walls;
floors and ceilings;
unvented low-slope roofs. 		Interior applications: must be covered with 1/2-inch gypsum board or other building-code approved material for fire safety.

Exterior applications: must be covered with weatherproof facing. 		High insulating value for relatively little thickness.

Can block thermal short circuits when installed continuously over frames or joists.
Loose-fill Cellulose
Fiberglass
Mineral (rock or slag) wool 		Enclosed existing wall or open new wall cavities;
unfinished attic floors;
hard-to-reach places. 		Blown into place using special equipment; sometimes poured in. Good for adding insulation to existing finished areas, irregularly shaped areas, and around obstructions.
Reflective system Foil-faced kraft paper, plastic film, polyethylene bubbles, or cardboard Unfinished walls, ceilings, and floors. Foils, films, or papers: fitted between wood-frame studs, joists, and beams Do-it-yourself.

All suitable for framing at standard spacing. Bubble-form suitable if framing is irregular or if obstructions are present.

Most effective at preventing downward heat flow; however, effectiveness depends on spacing.
Rigid fibrous or fiber insulation Fiberglass
Mineral (rock or slag) wool 		Ducts in unconditioned spaces and other places requiring insulation that can withstand high temperatures. HVAC contractors fabricate the insulation into ducts either at their shops or at the job sites. Can withstand high temperatures.
Sprayed foam and foamed-in-place Cementitious
Phenolic
Polyisocyanurate
Polyurethane 		Enclosed existing wall or open new wall cavities;
unfinished attic floors. 		Applied using small spray containers or in larger quantities as a pressure sprayed (foamed-in-place) product. Good for adding insulation to existing finished areas, irregularly shaped areas, and around obstructions.

These are all insulations for use in a standard wood or metal framed wall. Check out other wall systems and natural solutions for more options in creating a well insulated home.


To Pinpoint just where and how your home may be leaking precious climate controlled air, inspect areas around light fixtures (especially recessed), electrical outlets, attic access openings, old wood floors, cracks in walls, and gaps around windows.

Should you desire, there are testing companies which can determine where you might have air leaks by performing a blower door test. Yet, along with a tighter "building envelope" comes an increased necessity for controlled exchange and ventilation of fresh air. Don’t leak….breeeeathe!

See insulation innovations