Dallam County, TX Insulation Payback
Dallam County, TX: what topping up your attic actually costs
DOE classifies Dallam County as climate zone 4, mixed-dry — a wide swing between a hot dry summer and a cold winter. Its recommended attic R-value for bare joists is R-60. For an attic around 1,000 square feet, closing the gap from R-2 to R-60 costs around $3,480 and saves an estimated $1,416 a year — payback in roughly 2.5 years. That's about as fast as attic paybacks get.
Heating vs. cooling in Dallam County
The estimated savings split roughly $1,197/year heating, $220/year cooling. Out of every 100 US counties tracked here, Dallam County's savings potential beats roughly 47 of them. Within zone 4 specifically, it ranks 351st of 825 counties by estimated savings. Texas averages $1,035/year across the counties tracked here; Dallam County comes in 37% higher.
Where these numbers come from
The heating and cooling degree days behind this estimate — 4,475 HDD and 1,368 CDD (base 65°F, 1991-2020 normals) — come from DALHART, TX US, the nearest NOAA station with published normals, 16.1 miles from Dallam County's center. That combined heating-and-cooling load ranks Dallam County 1641st nationally by total degree days — the 48th percentile. Dallam County falls in DOE's moisture regime B (dry), a detail that affects vapor-barrier recommendations more than the R-value target itself.
If the attic isn't bare
If Dallam County's attic already has 3-4 inches of old insulation (about R-11) rather than bare joists, the recommended target drops to R-49. That smaller top-up costs around $2,280 and saves an estimated $207/year — payback about 11 years. This one is a genuine toss-up, not a clear yes.
Next steps for a Dallam 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 Dallam County, not a bid - contractors typically charge a $600 minimum regardless of job size.
Nothing here is a guess
Every figure on this page traces to DOE/IECC climate zones and NOAA degree-day normals, documented in the methodology guide. The guide to what R-value actually means explains why R-60 is the target here specifically.