California: Attic Insulation Payback by County

California: 55 counties covered

California spans DOE climate zones 2, 3, 4, 5, 6. Across its 55 counties tracked here, an uninsulated attic saves an estimated $1,056/year on average once topped up to the recommended R-value — actual savings depend on each county's own heating and cooling degree days, shown below.

• Modoc County — zone 5, ~$1,791/yr
• Mono County — zone 6, ~$1,715/yr
• Lassen County — zone 5, ~$1,633/yr
• Mariposa County — zone 4, ~$1,632/yr
• Plumas County — zone 5, ~$1,577/yr
• Sierra County — zone 5, ~$1,567/yr
• Nevada County — zone 5, ~$1,483/yr
• Siskiyou County — zone 5, ~$1,450/yr
• El Dorado County — zone 4, ~$1,426/yr
• Tuolumne County — zone 4, ~$1,351/yr
• Santa Clara County — zone 3, ~$1,291/yr
• Del Norte County — zone 4, ~$1,250/yr
• Mendocino County — zone 3, ~$1,232/yr
• Humboldt County — zone 4, ~$1,205/yr
• Kern County — zone 3, ~$1,192/yr
• Inyo County — zone 4, ~$1,188/yr
• Placer County — zone 3, ~$1,181/yr
• Trinity County — zone 4, ~$1,177/yr
• Lake County — zone 4, ~$1,118/yr
• Madera County — zone 3, ~$1,113/yr
• San Bernardino County — zone 3, ~$1,088/yr
• Glenn County — zone 3, ~$1,064/yr
• Yuba County — zone 3, ~$1,033/yr
• Contra Costa County — zone 3, ~$1,025/yr
• Butte County — zone 3, ~$1,005/yr
• Amador County — zone 4, ~$994/yr
• Napa County — zone 3, ~$992/yr
• San Mateo County — zone 3, ~$984/yr
• Calaveras County — zone 4, ~$977/yr
• Tehama County — zone 3, ~$977/yr
• Kings County — zone 3, ~$968/yr
• Merced County — zone 3, ~$928/yr
• Tulare County — zone 3, ~$920/yr
• Sutter County — zone 3, ~$916/yr
• Riverside County — zone 3, ~$912/yr
• San Benito County — zone 3, ~$905/yr
• Imperial County — zone 2, ~$903/yr
• Colusa County — zone 3, ~$898/yr
• Fresno County — zone 3, ~$893/yr
• Yolo County — zone 3, ~$871/yr
• San Francisco County — zone 3, ~$870/yr
• Stanislaus County — zone 3, ~$869/yr
• San Joaquin County — zone 3, ~$849/yr
• Sonoma County — zone 3, ~$836/yr
• Alameda County — zone 3, ~$826/yr
• Sacramento County — zone 3, ~$818/yr
• Solano County — zone 3, ~$789/yr
• Ventura County — zone 3, ~$789/yr
• Santa Barbara County — zone 3, ~$750/yr
• San Diego County — zone 3, ~$715/yr
• Monterey County — zone 3, ~$699/yr
• Santa Cruz County — zone 3, ~$689/yr
• San Luis Obispo County — zone 3, ~$605/yr
• Los Angeles County — zone 3, ~$593/yr
• Orange County — zone 3, ~$540/yr