Types of Insulation

Not all insulation is the same.  From traditional “blanket-type” fiberglass batting to sprayed-in foam, you have many insulation choices, and our guide here should help you make the best choice:

Type 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.
Concrete block insulation Foam beads or liquid foam:

  • Polystyrene
  • Polyisocyanurate or polyiso
  • Polyurethane

Vermiculite or perlite pellets

Unfinished walls, including foundation walls, for new construction or major renovations. Involves masonry skills. Autoclaved aerated concrete and autoclaved cellular concrete masonry units have 10 times the insulating value of conventional concrete.
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.

Insulating concrete forms (ICFs) Foam boards or foam blocks Unfinished walls, including foundation walls, for new construction. Installed as part of the building structure. Insulation is literally built into the home’s walls, creating high thermal resistance.
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.
Structural insulated panels (SIPs) Foam board or liquid foam insulation core
Straw core insulation
Unfinished walls, ceilings, floors, and roofs for new construction. Builders connect them together to construct a house. SIP-built houses provide superior and uniform insulation compared to more traditional construction methods; they also take less time to build.

–Content courtesy U.S. Department of Energy

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