Heat Pump Payback in Sumner, WA
Should Sumner switch to a heat pump?
Sumner technically pencils out, but only past the point the equipment would need replacing anyway. $5,500 is what Sumner would pay extra to go electric rather than replace the furnace and AC with the same again. Sumner's residents would see roughly $344 a year back in running costs, putting the payback around 16 years. That's a technicality, not a recommendation, for anyone actually living in Sumner.
Not the city you meant?
Sumner is one of 3206 cities covered here, each run through the same model. Search another below.
How cold Sumner actually gets
Degree days tell the story here: Sumner racks up 4867 heating degree days each year (base 65°F), and summers rarely ask much of an air conditioner, with 227 cooling degree days on the cooling side. The 99% winter design temperature here, the cold snap equipment must be sized for, not the seasonal average, is 17.6°F, and the coldest daily reading in the 2024 station record was 12.2°F. That puts the seasonal coefficient of performance at 3.12 for the recommended cold-climate unit. Below the 25°F line where a standard machine starts leaning on resistance backup, Sumner sits firmly in cold-climate territory, so that's the class of unit priced here. Climate figures trace to the nearest NOAA station, Pierce County Airport Thun Fi, 8.8 miles from Sumner.
What it actually costs to run, year to year
Electricity use for heating alone comes out to about 3,950 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $591 a year. That compares with roughly 51 Mcf a year of gas at Sumner's $17.62 per-Mcf rate, about $935 a year with the old AC included, against a local electricity rate of 14.27¢/kWh. Buying outright rather than at replacement time stretches payback to longer than the 15-year equipment life. Over 15 years, compared with a like-for-like replacement, the heat pump leaves you $343 behind.
How sensitive Sumner's result is to prices
Gas would only overtake the heat pump in Sumner if electricity rose past 23.2¢/kWh from 14.27¢, or gas fell under $10.84 per Mcf from $17.62. A useful quote test for Sumner: the heat pump is worth it within a decade if it costs less than $3,440 more than replacing the furnace and AC, and within 7 years if the gap is under $2,408.
If your home heats with electric baseboard instead of gas
Not every home in Sumner has gas service. Swap the comparison to resistance heat instead of gas, and Sumner's answer improves. Switching saves about $1,209 a year here, a heat pump moving heat rather than generating it needs far less electricity than resistance coils, so the extra $10,000 spent up front comes back in about 8.3 years.
Sumner against the rest of the country
Among 3206 cities, Sumner's winter puts it at rank 887 for severity, while its size puts it at rank 3008 for population, 1 in both cases being the extreme. That's the coldest third of the dataset, where climate does most of the work behind this figure.
Next step if you live in Sumner
Sumner, Washington is home to about 10,885 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 Sumner, nothing is lost by holding off until the current equipment genuinely fails.
Ask a local HVAC contractor for a quote before committing either way.
Where Sumner's figure comes from
Every constant behind this page, the 3.12 seasonal COP, the degree-day corrections, the equipment costs, is documented in the methodology guide. At a 17.6°F design temperature, Sumner sits in cold-climate territory; the guide to that class of unit explains why.