Missoula County, MT Insulation Payback
Is attic insulation worth it in Missoula County, MT?
Missoula County sits in IECC climate zone 6 (Cold) — winters that dominate the energy bill, with cooling a minor factor. 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 $1,975 a year in heating and cooling — a payback around 1.8 years. Few home upgrades pay back that quickly.
Heating vs. cooling in Missoula County
Heating accounts for about $1,921/year of that and cooling about $55/year — Missoula County needs both. Nationally, Missoula County ranks in the 81th percentile for insulation savings potential. Compared only against its own climate zone, Missoula County places 414th out of 459. Against Montana's own average of $2,182/year, Missoula County runs 9% below that.
The climate data behind this
The heating and cooling degree days behind this estimate — 7,183 HDD and 340 CDD (base 65°F, 1991-2020 normals) — come from MISSOULA 2 NE, MT US, the nearest NOAA station with published normals, 9.6 miles from Missoula County's center. That combined heating-and-cooling load ranks Missoula County 649th nationally by total degree days — the 80th percentile. Its moisture regime is classified dry, which matters for whether the attic needs a vapor retarder as part of the job — worth asking a contractor about locally.
Already have some insulation?
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 $288/year saved (~7.9-year payback). The math clears comfortably within a normal ownership horizon.
Quotes and materials for this job
Get more than one quote before committing. Attic access and any needed air sealing move the price around, and most contractors won't take a job below roughly $600 regardless of size - worth asking upfront given Missoula County's estimated $1,975/year on the line.
Missoula County's numbers, sourced
The methodology guide lists exactly which DOE and NOAA sources feed Missoula County's numbers, and where the cost assumptions come from. See the DIY vs. contractor guide for whether a job this size is realistic to do yourself.