Jefferson County, WA Insulation Payback
Attic insulation payback for Jefferson County, WA
Jefferson County, Washington is zone 4 under DOE's climate map (Marine), which means temperate and damp most of the year, with neither heating nor cooling asking for much. An uninsulated attic there should be built 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.
Where the savings come from
Of that, about $1,606/year comes from reduced heating and $13/year from reduced cooling load through the ceiling. Jefferson County beats 61% of the counties in this 3,162-county dataset on estimated insulation savings. Among the 825 counties DOE places in zone 4, Jefferson County ranks 34th. Against Washington's own average of $1,583/year, Jefferson County runs 2% above that.
Jefferson County's actual weather, not a national average
The heating and cooling degree days behind this estimate — 6,008 HDD and 81 CDD (base 65°F, 1991-2020 normals) — come from ELWHA RS, WA US, the nearest NOAA station with published normals, 14.9 miles from Jefferson County's center. Combined heating and cooling load puts Jefferson County in the 53th percentile of this 3,162-county dataset. DOE also classifies Jefferson County as moisture regime C (marine) - ask a local contractor whether that changes the vapor-barrier approach for this job.
Already have some insulation?
Already have a few inches up there? Topping R-11 up to R-49 runs about $2,280 for about $236/year saved — roughly 9.7 years to break even. It is close - the payback only just fits a reasonable timeframe.
Next steps for a Jefferson 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 Jefferson 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.