The usual attic target is R-38 to R-60 , but the right number depends on your climate zone and whether the attic is already insulated. For many U.S. homes, R-49 is a common middle-ground goal, while colder zones often call for R-60 or close to it.

Quick guide

  • Warm climates: R-30 to R-38.
  • Mixed climates: R-38 to R-49.
  • Cold climates: R-49 to R-60.

Easy rule of thumb

If you’re not sure, aim for R-49 in the attic unless you live in a colder region where R-60 is recommended. ENERGY STAR and the U.S. Department of Energy both show higher attic targets in colder climate zones.

If you want to check your attic

Measure the insulation depth and compare it with the material type, because actual R-value depends on thickness and insulation density. If you tell me your state or climate zone , I can give you the best attic R-value target for your area.