Navajo County, AZ Insulation Payback
Attic insulation payback for Navajo County, AZ
Navajo County sits in IECC climate zone 5 (Cold) — a real winter that drives most of the annual energy bill here. For a currently uninsulated attic, DOE and ENERGY STAR recommend building up to R-60. Topping up a typical 1,000-square-foot attic from bare joists (R-2) to R-60 runs an estimated $3,480, and saves about $1,619 a year in heating and cooling — a payback around 2.1 years. Hard to find a home improvement with a faster payback than this.
The breakdown behind the number
Of that, about $1,530/year comes from reduced heating and $89/year from reduced cooling load through the ceiling. Navajo County beats 61% of the counties in this 3,162-county dataset on estimated insulation savings. Among the 745 counties DOE places in zone 5, Navajo County ranks 617th. Against Arizona's own average of $1,149/year, Navajo County runs 41% above that.
Navajo County's actual weather, not a national average
The heating and cooling degree days behind this estimate — 5,722 HDD and 556 CDD (base 65°F, 1991-2020 normals) — come from KEAMS CANYON, AZ US, the nearest NOAA station with published normals, 29.9 miles from Navajo County's center. That combined heating-and-cooling load ranks Navajo County 1343rd nationally by total degree days — the 58th percentile. DOE also classifies Navajo County as moisture regime B (dry) - ask a local contractor whether that changes the vapor-barrier approach for this job.
The smaller top-up scenario
A shallower starting point changes the math: with R-11 already down, only the gap to R-49 needs filling, at roughly $2,280 for an estimated $236/year saved (~9.7-year payback). It is close - the payback only just fits a reasonable timeframe.
Next steps for a Navajo County attic
Actual quotes will vary by attic access, existing debris, and whether the job needs air sealing first. Treat the $3,480 figure above as a planning number for Navajo County, not a bid - contractors typically charge a $600 minimum regardless of job size.
More on how this was built
Nothing here is a guess: the methodology guide names the DOE climate map and NOAA station data behind every number on this page. See the DIY vs. contractor guide for whether a job this size is realistic to do yourself.