Funded by the Local Government Strategic Plan Strategies Program

under the auspices of the California Public Utilities Commission.



Air that leaks through your home's envelope − the outer walls, windows, doors, and other openings − wastes a lot of energy and increases your utility costs. A well-sealed envelope, coupled with the right amount of insulation, can make a real difference on your utility bills.

What can you do about it?

Add insulation to your attic.

One of the most cost-effective ways to make your home more comfortable year-round is to add insulation to your attic. Adding insulation to the attic is relatively easy. To find out if you have enough before adding more, measure the thickness of the insulation that’s currently installed. If it’s less than R-30 (11 inches of fiberglass or rock wool, or 8 inches of cellulose), you could probably benefit by adding more.

Types of insulation.

What is an R-Value?

Insulation is measured in R-values—the higher the R-value, the better your walls and roof will resist the transfer of heat. The DOE recommends ranges of R-values based on local heating and cooling costs, as well as climate conditions in different areas of the country.

Should you consider adding insulation? 

Consider adding insulation if any of these apply to you:

  • You have an older home and haven't added insulation. Only 20% of homes built before 1980 are adequately insulated, as insulation degrades over time.

  • You are uncomfortably cold in the winter or hot in the summer. Adding insulation creates a more uniform temperature and increases comfort.

  • You build a new home or addition, or install new siding or roofing.

  • You pay too much for your energy bills.

  • You’re bothered by noise from outside. Insulation muffles sound.