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

St. Marys clears a genuine payback here, inside a reasonable stretch of years. $1,000 is what St. Marys 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. That premium is recovered through $289 of lower running costs every year, landing the payback clock at roughly 3.5 years. The window here is reasonable, and it's specific to what St. Marys actually pays for power and gas.

St. Marys's weather, in the numbers that matter

St. Marys barely has a winter to speak of — 1250 heating degree days a year against a 65°F base — and summers are severe enough that cooling can dominate the annual bill, at 2693 cooling degree days. The 99% winter design temperature here — the cold snap equipment must be sized for, not the seasonal average — is 28.6°F, against a record low of 27.1°F. That puts the seasonal coefficient of performance at 3.05 for the recommended standard unit. St. Marys's winters don't get cold enough to need the cold-climate premium — a standard unit holds up fine. These numbers come from BRUNSWICK 23 S , the closest NOAA station, 7.9 miles out.

The month-to-month numbers for St. Marys

Electricity use for heating alone comes out to about 1,038 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $497 a year. St. Marys's gas rate of 20.42 per Mcf, applied to the 13 Mcf a year the furnace burns, puts its running cost near $786 a year, against 14.90¢ per kWh for electricity. Buy it outright, not incrementally, and payback stretches to 38 years; over 15 years the net position sits $3,337 ahead.

Electric resistance heat in St. Marys, compared

Not every home in St. Marys has gas service. Against electric-resistance heat — baseboard or an electric furnace, both 100% efficient but still just resistance — the case for switching gets stronger here. The saving here runs about $495 a year, which recovers the extra $5,500 spent going electric in roughly 11.1 years.

St. Marys against the rest of the country

Ranked against the other 3206 cities covered, St. Marys comes in at 2784 for heating severity — 1 would be the coldest place in the dataset — and 1912 by population, where 1 is largest. That's the mildest third of cities covered, where utility rates carry more of the answer than climate does.

What to do with this number in St. Marys

St. Marys, Georgia is home to about 20,119 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. Given the math above, St. Marys is a place worth lining up quotes ahead of a breakdown, not waiting for one.

Get quotes from local HVAC contractors before deciding.

More on how this number was built

Every constant behind this page — the 3.05 seasonal COP, the degree-day corrections, the equipment costs — is documented in the methodology guide. The $2,000 federal credit baked into St. Marys's number is explained, with the before-and-after math, in the tax credit guide.