Heat Pump Payback in Sammamish, WA
Will a heat pump pay off in Sammamish, WA?
Sammamish technically pencils out, but only past the point the equipment would need replacing anyway. Swap a failed furnace and AC for a heat pump rather than buying like-for-like, and the extra cost here runs $5,500. That premium is recovered through $315 of lower running costs every year, landing the payback clock at roughly 17.5 years. That's a technicality, not a recommendation, for anyone actually living in Sammamish.
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Sammamish is one of 3206 cities covered here, each run through the same model. Search another below.
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, and the coldest daily reading in the 2024 station record was 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 the current furnace-and-AC running cost near $834 a year, against 14.27¢ per kWh for electricity. If the current system still worked and you replaced it anyway, the full cost would take longer than the 15-year equipment life to earn back; against buying a new furnace and AC regardless, the 15-year total lands $775 behind.
How sensitive Sammamish's result is to prices
Gas would only overtake the heat pump in Sammamish if electricity rose past 24.2¢/kWh from 14.27¢, or gas fell under $10.40 per Mcf from $17.62. A useful quote test for Sammamish: the heat pump is worth it within a decade if it costs less than $3,150 more than replacing the furnace and AC, and within 7 years if the gap is under $2,205.
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 9.4-year payback clears the $10,000 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.