How Much Insulation is Needed in a Ceiling?

The amount of insulation needed in your ceiling depends on the climate where you live. In areas that require significant heating during the winter, more attic insulation is recommended. If you live in an area where you need to run your air conditioner throughout the summer, more attic insulation will save you money.

The type of heating and cooling system you have in your house also will affect the amount of insulation needed.

Regional information

The least amount of attic insulation is needed in Florida, Hawaii, coastal California, southeast Texas, and the southern areas of Louisiana, Arkansas, Mississippi, Alabama and Georgia. For homes in these areas that are heated with either heating oil, gas, or a heat pump, attics should have insulation rated between R-22 and R-38 a value that indicates how well the insulation "resists" heat transfer. Materials with a higher R value insulate better.

If you live in one of these areas and heat your home with electric resistance heaters, such as baseboard heaters, you need more insulation, between R-38 and R-49.

Homes heated with oil, gas, or heat pumps in the colder areas of the United States should have attic insulation rated from R-38 to R-49. These areas have snowy mountainous areas, the New England states, the northern Midwest. If you live in any of those areas and heat your home with electric resistance heaters, you should have insulation rated at R-49.

In areas that have moderate heating and cooling requirements throughout the year, such as most of the Southeast, the Northwest, inland California, Nevada, and the more moderate areas in the Midwest, attics should be insulated to a level of R-38.

Insulation types

The most common attic insulation is the fiberglass blanket that comes in rolls. It is popular with homeowners because it is easy to install. It comes in various widths and R ratings. R-38 insulation would be 12 inches thick when unrolled in your attic. This type of insulation usually has a paper backing on one side that acts as a vapor barrier.

Blown-in attic fiberglass or cellulose insulation are also popular, although this insulation usually requires professional installation.

Government information

The U.S. Department of Energy has good information on all types of home insulation, including some online calculators, to help determine the insulation requirements and costs for your location.