Should Plymouth switch to a heat pump?
Plymouth is a place where a heat pump genuinely costs more to operate than the alternative. Against a like-for-like gas furnace and AC swap, going electric costs $3,500 more up front here (already netting out a $2,000 tax credit). Unfortunately the electric bill outweighs the gas bill it replaces by about $213 a year here, so the extra spend stays unrecovered. There's no spin on that: Plymouth's numbers say wait.
Why Plymouth's climate drives this number
6208 heating degree days pile up here every year, so Plymouth has a cold winter that leans hard on heating equipment; the cooling side runs to 735 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 -7.1°F, against a record low of -9°F. That puts the seasonal coefficient of performance at 2.53 for the recommended cold-climate unit. Plymouth 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 CRYSTAL AIRPORT, the closest NOAA station, 6.1 miles out.
Plymouth's running-cost comparison, in dollars
Modelled on a typical 2000-square-foot house, the heat pump draws about 6,213 kWh a year to keep it warm, plus cooling, for a combined electric bill near $1,072 a year. The gas furnace it replaces burns roughly 65 Mcf a year at 10.98 per Mcf here, for a running cost near $859 a year (electricity here runs 15.67¢/kWh). Buy it outright, not incrementally, and payback stretches to beyond the 15-year equipment life; over 15 years the net position sits $6,690 behind.
The other scenario: no gas furnace to begin with
Gas isn't universal in Plymouth — many houses run on electric heat already. Against electric-resistance heat — baseboard or an electric furnace, both 100% efficient but still just resistance — the case for switching gets stronger here. Switching saves about $1,541 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 5.2 years.
Plymouth against the rest of the country
Plymouth lands at position 147 out of 3206 cities on heating severity (coldest is 1), and 477 out of 3206 by population size (biggest is 1). That's the coldest third of the dataset, where climate does most of the work behind this figure.
Deciding what's next in Plymouth, MN
About 78,551 people live in Plymouth, Minnesota, 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.
Where Plymouth's figure comes from
The methodology guide walks through exactly how Plymouth's 2.53 seasonal COP and the rest of this page's numbers get built. Plymouth's -7.1°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.