Heat Pump Payback in Mill Creek, WA
Is a heat pump worth it in Mill Creek?
In Mill Creek, the extra upfront cost technically comes back, just not before the equipment wears out. $5,500 is what Mill Creek would pay extra to go electric rather than replace the furnace and AC with the same again. Mill Creek's residents would see roughly $318 a year back in running costs, putting the payback around 17.3 years. Mill Creek's own numbers say this pencils out only in theory, not in practice.
Compare against another city
This runs the same numbers for 3206 US cities, not just Mill Creek. Look one up here.
Why Mill Creek's climate drives this number
4489 heating degree days pile up here every year, so Mill Creek has a real but manageable winter; the cooling side runs to 200 cooling degree days, where summers rarely ask much of an air conditioner. 18°F is the figure equipment gets sized against here, the 99th-percentile cold snap, not an average day, with a low of 12.9°F in the 2024 station record. Worked through the model, that's a seasonal COP of 3.13 on the cold-climate unit fit for this climate. A cold-climate unit is the right call in Mill Creek, below 25°F design temperature, a standard heat pump leans hard on electric-resistance backup, which erases most of the savings. Climate figures trace to the nearest NOAA station, Snohomish Co (Paine Fd) AP, 4.4 miles from Mill Creek.
What it actually costs to run, year to year
Modelled on a typical 2000-square-foot house, the heat pump draws about 3,632 kWh a year to keep it warm, plus cooling, for a combined electric bill near $543 a year. The gas furnace it replaces burns roughly 47 Mcf a year at $17.62 per Mcf here, for a running cost near $861 a year including the old AC (electricity here runs 14.27¢/kWh). 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 $727 behind.
The break-even point in Mill Creek
This result holds unless electricity climbs above 23.3¢/kWh (it is 14.27¢ now) or gas drops below $10.81 per Mcf (now $17.62); past either point, gas becomes the cheaper fuel in Mill Creek. When quotes arrive, compare the heat pump price with a like-for-like furnace and AC replacement: at $318 a year saved, a difference under $2,226 pays back within 7 years here, and under $3,180 within 10.
If your home heats with electric baseboard instead of gas
Not every home in Mill Creek has gas service. Swap the comparison to resistance heat instead of gas, and Mill Creek's answer improves. About $1,116 a year comes back this way, enough that the 9-year payback clears the $10,000 premium comfortably within the equipment's life.
Mill Creek against the rest of the country
Among 3206 cities, Mill Creek's winter puts it at rank 1209 for severity, while its size puts it at rank 1849 for population, 1 in both cases being the extreme. That's the middle third for winter severity among the cities covered here.
Deciding what's next in Mill Creek, WA
About 20,993 people live in Mill Creek, Washington, and every number on this page is what a contractor would actually work from when quoting a system here, the point isn't to replace that quote, it's to tell you whether to bother asking for one. Here, there's no cost penalty to waiting until your current furnace or AC actually needs replacing.
Ask a local HVAC contractor for a quote before committing either way.
More on how this number was built
Every constant behind this page, the 3.13 seasonal COP, the degree-day corrections, the equipment costs, is documented in the methodology guide. Mill Creek's 18°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.