Collin County, TX Insulation Payback
Collin County, TX: what topping up your attic actually costs
Collin County sits in IECC climate zone 3 (Hot-Humid) — humid heat for much of the year, with cooling running far more than heating ever does. For a currently uninsulated attic, DOE and ENERGY STAR recommend building up to 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 2.7 years at an estimated $1,029/year saved. That's about as fast as attic paybacks get.
Where the savings come from
The estimated savings split roughly $644/year heating, $385/year cooling. Out of every 100 US counties tracked here, Collin County's savings potential beats roughly 19 of them. Within zone 3 specifically, it ranks 414th of 690 counties by estimated savings. Texas averages $1,035/year across the counties tracked here; Collin County comes in 1% lower.
Collin County's actual weather, not a national average
The heating and cooling degree days behind this estimate — 2,429 HDD and 2,416 CDD (base 65°F, 1991-2020 normals) — come from MCKINNEY MUNICIPAL AIRPORT, TX US, the nearest NOAA station with published normals, 0.8 miles from Collin County's center. Combined heating and cooling load puts Collin County in the 21th percentile of this 3,162-county dataset. Collin County falls in DOE's moisture regime A (humid), a detail that affects vapor-barrier recommendations more than the R-value target itself.
If the attic isn't bare
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 $139/year saved (~11.7-year payback). This one is a genuine toss-up, not a clear yes.
Getting it done in Collin County
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 Collin 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-49 is the target here specifically.