Is attic insulation worth it where you live?
DOE climate zones and NOAA degree-day data for 3,162 US counties show what topping up your attic actually costs, saves, and pays back — a planning estimate for your county, not a contractor's quote for your house, free, and it depends more on whether your attic already has some insulation than most people expect.
Covers 3,162 US counties. Start typing yours.
The same calculation, four climates
Every county page runs this exact DOE/NOAA-based math for a typical 1,000 sq ft attic, only the climate and the starting insulation level change. Going from bare joists is almost always worth it, fast. Topping up an attic that already has a few inches down is a much closer call, same county, same climate, very different answer.
| County | Bare attic to code | Already has some? |
|---|---|---|
| North Slope Borough, AK coldest county in the dataset |
$3,480 → saves $5,016/yr 0.7-year payback |
$2,280 → saves $732/yr 3.1-year payback |
| Franklin County, OH typical cold-winter metro |
$3,480 → saves $1,608/yr 2.2-year payback |
$2,280 → saves $235/yr 9.7-year payback |
| Harris County, TX mixed, cooling-heavy climate |
$2,820 → saves $860/yr 3.3-year payback |
$1,620 → saves $116/yr 14-year payback |
| Río Grande Municipio, PR mildest county in the dataset |
$1,680 → saves $166/yr 10.1-year payback |
$840 → saves $18/yr 46.4-year payback |
What the number depends on
- Your county's actual heating and cooling degree days, NOAA 1991-2020 normals, not a national average
- DOE's recommended R-value for your climate zone, and whether the attic is bare joists or already has 3-4 inches down
- A typical 1,000 sq ft attic at national average install cost and energy prices, your attic's real size and your local utility rates will move the number from here
Browse all 3,162 counties by state
- Alabama64
- Alaska28
- Arizona15
- Arkansas74
- California55
- Colorado61
- Delaware3
- District of Columbia1
- Florida64
- Georgia157
- Hawaii5
- Idaho44
- Illinois100
- Indiana90
- Iowa99
- Kansas103
- Kentucky119
- Louisiana62
- Maine16
- Maryland23
- Massachusetts14
- Michigan83
- Minnesota87
- Mississippi82
- Missouri115
- Montana56
- Nebraska89
- Nevada17
- New Hampshire10
- New Jersey21
- New Mexico32
- New York61
- North Carolina99
- North Dakota53
- Ohio88
- Oklahoma76
- Oregon36
- Pennsylvania66
- PR73
- Rhode Island5
- South Carolina45
- South Dakota66
- Tennessee95
- Texas250
- Utah26
- Vermont14
- Virginia133
- Washington38
- West Virginia55
- Wisconsin72
- Wyoming22
Where these numbers come from
Every figure on this site is computed from DOE/IECC climate zone assignments and NOAA 1991-2020 heating and cooling degree-day normals for 3,162 US counties across 51 states and 8 climate zones, averaging $1,510/year saved and a 2.3-year payback for a typical uninsulated attic, before your own county moves that number. The methodology guide lists the exact sources and cost assumptions behind the calculation above.