Washington County, UT Insulation Payback
Washington County attic insulation, by the numbers
DOE classifies Washington County as climate zone 3, hot-dry — scorching, dry summers where heat radiating straight through the roof does most of the damage. Its recommended attic R-value for bare joists is R-49. Going from R-2 to the recommended R-49 costs roughly $2,820 installed for a typical attic (about 1,000 sq ft), and pays for itself in about 2.1 years at an estimated $1,323/year saved. Topping up the attic pays for itself fast here.
Where the savings come from
Split it out and it's roughly $1,130 a year on the heating side, $193 on cooling. By estimated insulation savings, Washington County lands in the 40th percentile nationally. Zone 3 alone covers 690 counties in this dataset, and Washington County comes in 21st by savings. Utah averages $1,791/year across the counties tracked here; Washington County comes in 26% lower.
Where these numbers come from
Washington County's climate figures — 4,258 heating and 1,211 cooling degree days a year — are read from VEYO POWERHOUSE, UT US, 11.6 miles away, NOAA's nearest 1991-2020 normals station. By total degree days, Washington County sits at the 39th percentile nationally. One local detail the R-value alone won't tell you: Washington County sits in moisture regime B (dry), which can affect the vapor-barrier choice.
The smaller top-up scenario
A shallower starting point changes the math: with R-11 already down, only the gap to R-38 needs filling, at roughly $1,620 for an estimated $178/year saved (~9.1-year payback). Call this borderline rather than a clear win.
Quotes and materials for this job
Actual quotes will vary by attic access, existing debris, and whether the job needs air sealing first. Treat the $2,820 figure above as a planning number for Washington County, not a bid - contractors typically charge a $600 minimum regardless of job size.
Where these figures come from
Washington County's R-49 target and its degree-day figures both come from named federal sources - see the methodology guide for exactly which ones. The guide to what R-value actually means explains why R-49 is the target here specifically.