Is a heat pump worth it in Charleston?

Charleston technically pencils out, but only past the point the equipment would need replacing anyway. 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). That premium is recovered through $133 of lower running costs every year, landing the payback clock at roughly 26.3 years. That's a technicality, not a recommendation, for anyone actually living in Charleston.

Charleston's weather, in the numbers that matter

Charleston has a real but manageable winter — 3697 heating degree days a year against a 65°F base — and summers are hot enough that cooling matters as much as heating, at 1356 cooling degree days. Sizing runs off the design temperature, not the average day: 10°F here (record low 6.1°F), which works out to a seasonal COP of 2.94 for the cold-climate class of unit this climate calls for. Charleston 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. Source: NOAA station YEAGER AIRPORT, 3.1 miles from Charleston — the closest one on record.

The month-to-month numbers for Charleston

Electricity use for heating alone comes out to about 3,184 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $669 a year. That compares with roughly 39 Mcf a year of gas at Charleston's 13.80 per-Mcf rate — about $802 a year — against a local electricity rate of 15.41¢/kWh. Looked at as a full purchase rather than an incremental one, payback here is roughly 101.3 years, leaving the 15-year total $1,500 behind.

Electric resistance heat in Charleston, compared

Plenty of homes in Charleston heat with electricity alone, no gas line involved. 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 $1,045 a year, which recovers the extra $8,000 spent going electric in roughly 7.7 years.

Where Charleston ranks in this dataset

Among 3206 cities, Charleston's winter puts it at rank 1682 for severity, while its size puts it at rank 880 for population — 1 in both cases being the extreme. That's the middle third for winter severity among the cities covered here.

Next step for 46,482 people in Charleston

Charleston, West Virginia is home to about 46,482 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 Charleston, 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 Charleston's figure comes from

The methodology guide walks through exactly how Charleston's 2.94 seasonal COP and the rest of this page's numbers get built. Charleston's 10°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.