Heat pump vs. gas furnace in St. Marys, PA

Here in St. Marys, the honest answer is that a heat pump raises your annual running cost. 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 $173 a year here, so the extra spend stays unrecovered. There's no spin on that: St. Marys's numbers say wait.

Why St. Marys's climate drives this number

St. Marys has a cold winter that leans hard on heating equipment — 5757 heating degree days a year against a 65°F base — and summers add a moderate cooling load, at 490 cooling degree days. Sizing runs off the design temperature, not the average day: 0°F here (record low -5.1°F), which works out to a seasonal COP of 2.7 for the cold-climate class of unit this climate calls for. Below the 25°F line where a standard machine starts leaning on resistance backup, St. Marys sits firmly in cold-climate territory, so that's the class of unit priced here. Source: NOAA station BRADFORD REGIONAL AIRPORT, 24.4 miles from St. Marys — the closest one on record.

What it actually costs to run, year to year

Modelled on a typical 2000-square-foot house, the heat pump draws about 5,399 kWh a year to keep it warm, plus cooling, for a combined electric bill near $1,207 a year. That compares with roughly 60 Mcf a year of gas at St. Marys's 15.04 per-Mcf rate — about $1,034 a year — against a local electricity rate of 20.75¢/kWh. Priced as a standalone purchase rather than against a like-for-like replacement, equipment payback runs past the 15-year equipment life, for a 15-year net position $6,102 behind.

The other scenario: no gas furnace to begin with

Gas isn't universal in St. Marys — many houses run on electric heat already. Swap the comparison to resistance heat instead of gas, and St. Marys's answer improves. The saving here runs about $1,950 a year, which recovers the extra $8,000 spent going electric in roughly 4.1 years.

St. Marys against the rest of the country

Among 3206 cities, St. Marys's winter puts it at rank 297 for severity, while its size puts it at rank 2754 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.

What to do with this number in St. Marys

About 12,361 people live in St. Marys, Pennsylvania, 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.

Get quotes from local HVAC contractors before deciding.

Reading further on this page's numbers

The methodology guide walks through exactly how St. Marys's 2.7 seasonal COP and the rest of this page's numbers get built. St. Marys's 0°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.