Which Type of Insulation Works Best?

Insulation Terms

• When shopping for insulation, you will likely encounter a number of technical terms that you should have a basic familiarity with. The most common type of insulation is made of fiberglass that is cut with a utility knife. This type of insulation is often referred to as "batt" or "blanket" insulation. "R-value" is a unit of measurement to quantify resistance to heat flow. The greater the R-value rating, the greater the resistance. The term "British Thermal Unit (BTU)" is a measurement of heat. One BTU is required to increase the temperature of 1 lb. of water by 1 degree F.

Recommended R-Values

• Recommended R-values depend on the insulated area in relation to the climate where the residence is located. If insulating an attic, an R-rating of 38 may be appropriate to use in a northern zone while a rating of 30 in a temperate zone and 26 in a southern zone may work best. An R-rating of 19 is frequently used throughout the U.S. for walls. Floors may call for a rating of 22 in a northern zone, 13 in a temperate zone and 11 in a southern zone.

Common Insulation Types

• Fiberglass is the most common type of insulation and is fairly straightforward to work with. However, it can irritate eyes, skin and the respiratory system, so protective attire should be worn when working with fiberglass. Loose fill cellulose is typically made from recycled newspaper. Unlike with fiberglass insulation, loose fill cellulose is treated with fire retardant. As with fiberglass, loose fill can irritate skin, eyes and the respiratory system. Extruded polystyrene insulation is sometimes referred to as rigid board insulation. It is generally a better insulator than other types and is comparatively thinner, but it does cost more. Polyurethane foam is usually sold in an aerosol spray can and is designed to reach narrow crevices.

Insulation for Common Applications

• Fiberglass insulation is commonly used to insulate walls, ceilings and other large areas. Loose fill cellulose is designed to be poured in between floor joists or blown into wall cavities. Extruded polystyrene is commonly used to insulate exterior foundation walls and under slabs. Polyurethane foam is most commonly used against air leaks that exist in areas that are too small to access with traditional types of fiberglass.