Will a heat pump pay off in Mount Pleasant, SC?
Mount Pleasant clears a genuine payback here, inside a reasonable stretch of years. Against a like-for-like gas furnace and AC swap, going electric costs $1,000 more up front here (already netting out a $2,000 tax credit). That premium is recovered through $240 of lower running costs every year, landing the payback clock at roughly 4.2 years. The window here is reasonable, and it's specific to what Mount Pleasant actually pays for power and gas.
Mount Pleasant's weather, in the numbers that matter
Mount Pleasant barely has a winter to speak of — 1430 heating degree days a year against a 65°F base — and summers are hot enough that cooling matters as much as heating, at 2383 cooling degree days. The 99% winter design temperature here — the cold snap equipment must be sized for, not the seasonal average — is 33.4°F, against a record low of 25°F. That puts the seasonal coefficient of performance at 3.2 for the recommended standard unit. Mount Pleasant's winters don't get cold enough to need the cold-climate premium — a standard unit holds up fine. Source: NOAA station CHARLESTON, 3.9 miles from Mount Pleasant — 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 1,132 kWh a year to keep it warm, plus cooling, for a combined electric bill near $511 a year. Mount Pleasant's gas rate of 16.91 per Mcf, applied to the 15 Mcf a year the furnace burns, puts its running cost near $751 a year, against 16.16¢ per kWh for electricity. Buy it outright, not incrementally, and payback stretches to 45.9 years; over 15 years the net position sits $2,596 ahead.
The other scenario: no gas furnace to begin with
Gas isn't universal in Mount Pleasant — many houses run on electric heat already. Compared with baseboard or electric-furnace resistance heat, the numbers shift in the heat pump’s favor. The saving here runs about $573 a year, which recovers the extra $5,500 spent going electric in roughly 9.6 years.
Mount Pleasant against the rest of the country
Ranked against the other 3206 cities covered, Mount Pleasant comes in at 2714 for heating severity — 1 would be the coldest place in the dataset — and 361 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 Mount Pleasant
Mount Pleasant, South Carolina is home to about 95,604 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, Mount Pleasant is a place worth lining up quotes ahead of a breakdown, not waiting for one.
Line up a few local HVAC quotes before you decide.
More on how this number was built
Every constant behind this page — the 3.2 seasonal COP, the degree-day corrections, the equipment costs — is documented in the methodology guide. The $2,000 federal credit baked into Mount Pleasant's number is explained, with the before-and-after math, in the tax credit guide.