Is a heat pump worth it in Mukilteo?

This one's marginal in Mukilteo: it only clears if you stay long enough. $3,500 is what Mukilteo would pay extra to go electric rather than replace the furnace and AC with the same again, once the $2,000 federal credit is applied. Mukilteo's residents would see roughly $318 a year back in running costs, putting the payback around 11 years. It's a genuine toss-up here — Mukilteo's numbers don't point clearly either way.

Mukilteo's weather, in the numbers that matter

4489 heating degree days pile up here every year, so Mukilteo has a real but manageable winter; the cooling side runs to 200 cooling degree days, where summers rarely ask much of an air conditioner. Sizing runs off the design temperature, not the average day: 18°F here (record low 12.9°F), which works out to a seasonal COP of 3.13 for the cold-climate class of unit this climate calls for. A cold-climate unit is the right call in Mukilteo — 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, 1.1 miles from Mukilteo.

The month-to-month numbers for Mukilteo

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. Mukilteo's gas rate of 17.62 per Mcf, applied to the 47 Mcf a year the furnace burns, puts its running cost near $861 a year, against 14.27¢ per kWh for electricity. Priced as a standalone purchase rather than against a like-for-like replacement, equipment payback runs about 42.4 years, for a 15-year net position $1,273 ahead.

The other scenario: no gas furnace to begin with

Not every home in Mukilteo has gas service. Swap the comparison to resistance heat instead of gas, and Mukilteo's answer improves. Switching saves about $1,116 a year here — a heat pump moving heat rather than generating it needs far less electricity than resistance coils — so the extra $8,000 spent up front comes back in about 7.2 years.

Where Mukilteo ranks in this dataset

Ranked against the other 3206 cities covered, Mukilteo comes in at 1208 for heating severity — 1 would be the coldest place in the dataset — and 1825 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 Mukilteo

Mukilteo, Washington is home to about 21,299 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 Mukilteo, nothing is lost by holding off until the current equipment genuinely fails.

Line up a few local HVAC quotes before you decide.

Reading further on this page's numbers

The methodology guide walks through exactly how Mukilteo's 3.13 seasonal COP and the rest of this page's numbers get built. Mukilteo's 18°F design temperature falls on the cold side of the 25°F cutoff the cold-climate unit guide walks through.