UNITS / TERMS:
Insulation level is specified by R-value. R-value is a measure of insulation's ability to resist heat traveling through it. The higher the R-value, the better the thermal performance of the insulation. Add the R-values of individual components of a wall or ceiling assembly to calculate the total R-value.
Types of wall insulation include but are not limited to:
Fiberglass and rock wool batts - generally the most inexpensive wall insulation. Requires careful installation for effective performance.
Cellulose insulation - made from recycled newsprint, usually loose-fill. Reduced air leakage and improved sound deadening.
Fiberglass and rock wool loosefill insulation - full coverage that involves blowing insulation into open stud cavities.
Rigid foam insulation - higher R-value per inch than fiberglass or cellulose insulation. Stops air leaks. Considerably more expensive.
Foam-in-place insulation - blown into walls, reduces air leakage. Some manufacturers use carbon dioxide in the manufacturing process rather than more environmentally harmful gases such as pentane or hydrofluorocarbons.
BACKGROUND FACTS:
Properly sealed, moisture protected, and insulated walls help increase comfort, reduce noise, and save energy.
The keys to an effective wall are airtight construction, moisture control, and complete insulation coverage.
Insulating ceilings is one of the most cost-effective measures for reducing heat loss in the winter, reducing heat gain in the summer, and providing an even temperature distribution throughout the house.
Recommended R-values for wall, ceiling, attic, and basement insulation vary depending on climate. Specific recommended R-values appear in the reading materials for this section. For most parts of the U.S., the Department of Energy recommends at least R-38 for ceilings, R-21 for walls, R-10+ for foundations, and insulated doors.
U.S. Department of Energy's Buildings for the 21st Century: Wall Insulation
U.S. Department of Energy's Buildings for the 21st Century: Ceilings and Attics
U.S. Department of Energy's Buildings for the 21st Century: Basement Insulation
Energy Star: Recommended Levels of Insulation
ColoradoENERGY.org: Calculating Savings - Adding Insulation
ColoradoENERGY.org: R-Value Table
