Knox County, ME Insulation Payback
Attic insulation payback for Knox County, ME
Knox County sits in IECC climate zone 6 (Cold) — cold enough that heating, not cooling, is what decides the bill. For a currently uninsulated attic, DOE and ENERGY STAR recommend building up to 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 $1,858 a year — payback in roughly 1.9 years. Hard to find a home improvement with a faster payback than this.
Where the savings come from
Of that, about $1,839/year comes from reduced heating and $20/year from reduced cooling load through the ceiling. Knox County beats 76% of the counties in this 3,162-county dataset on estimated insulation savings. Among the 459 counties DOE places in zone 6, Knox County ranks 448th. Against Maine's own average of $2,159/year, Knox County runs 14% below that.
Knox County's actual weather, not a national average
NOAA's TENANTS HARBOR, ME US station, 9.5 miles from Knox County, supplies the 6,877 HDD and 122 CDD this estimate runs on. Combined heating and cooling load puts Knox County in the 71th percentile of this 3,162-county dataset. DOE also classifies Knox County as moisture regime A (humid) - ask a local contractor whether that changes the vapor-barrier approach for this job.
The smaller top-up scenario
If Knox 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 $271/year — payback about 8.4 years. It is close - the payback only just fits a reasonable timeframe.
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 $3,480 figure above as a planning number for Knox 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.