Will a heat pump pay off in Sammamish, WA?
Sammamish sits right on the fence — how long you'll own the house decides this one. Swap a failed furnace and AC for a heat pump rather than buying like-for-like, and the extra cost here runs $3,500 after a $2,000 federal tax credit. That premium is recovered through $315 of lower running costs every year, landing the payback clock at roughly 11.1 years. It's a genuine toss-up here — Sammamish's numbers don't point clearly either way.
Sammamish's weather, in the numbers that matter
4187 heating degree days pile up here every year, so Sammamish has a real but manageable winter; the cooling side runs to 354 cooling degree days, where summers add a moderate cooling load. The 99% winter design temperature here — the cold snap equipment must be sized for, not the seasonal average — is 19.9°F, against a record low of 17.1°F. That puts the seasonal coefficient of performance at 3.18 for the recommended cold-climate unit. Sammamish needs the cold-climate class of unit: past a 25°F design temperature a standard heat pump falls back on resistance backup often enough to eat the savings. These numbers come from RENTON MUNICIPAL AIRPORT, the closest NOAA station, 10.8 miles out.
What it actually costs to run, year to year
A 2000-square-foot house here would pull roughly 3,334 heating kilowatt-hours annually on top of cooling, totalling about $519 a year on electricity. Sammamish's gas rate of 17.62 per Mcf, applied to the 44 Mcf a year the furnace burns, puts its running cost near $834 a year, against 14.27¢ per kWh for electricity. Looked at as a full purchase rather than an incremental one, payback here is roughly 42.9 years, leaving the 15-year total $1,225 ahead.
The other scenario: no gas furnace to begin with
Not every home in Sammamish has gas service. Against electric-resistance heat — baseboard or an electric furnace, both 100% efficient but still just resistance — the case for switching gets stronger here. About $1,060 a year comes back this way, enough that the 7.6-year payback clears the $8,000 premium comfortably within the equipment's life.
Where Sammamish ranks in this dataset
Ranked against the other 3206 cities covered, Sammamish comes in at 1405 for heating severity — 1 would be the coldest place in the dataset — and 591 by population, where 1 is largest. That's the middle third for winter severity among the cities covered here.
What to do with this number in Sammamish
Sammamish, Washington is home to about 66,474 people, and the figures above are the same ones a local HVAC contractor uses to size and quote a system — this site doesn't guess where a real quote would land, it just tells you whether it's worth asking for one. In Sammamish, nothing is lost by holding off until the current equipment genuinely fails.
Ask a local HVAC contractor for a quote before committing either way.
Reading further on this page's numbers
Nothing above is a black box: the methodology guide shows the full arithmetic behind Sammamish's 3.18 seasonal COP and payback figure. Sammamish's 19.9°F design temperature is below the 25°F line, which is why a cold-climate unit is the right call here — see what that changes in the cold-climate unit guide.