Heat pump vs. gas furnace in Rock Hill, SC
Rock Hill 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). Rock Hill's residents would see roughly $230 a year back in running costs, putting the payback around 15.2 years. Rock Hill's own numbers say this pencils out only in theory, not in practice.
Why Rock Hill's climate drives this number
Rock Hill has a mild winter by US standards — 2789 heating degree days a year against a 65°F base — and summers are hot enough that cooling matters as much as heating, at 1564 cooling degree days. 15.1°F is the figure equipment gets sized against here — the 99th-percentile cold snap, not an average day — with a record low of 10.9°F on file. Worked through the model, that's a seasonal COP of 3.06 on the cold-climate unit fit for this climate. A cold-climate unit is the right call in Rock Hill — below 25°F design temperature, a standard heat pump leans hard on electric-resistance backup, which erases most of the savings. Source: NOAA station RK HL/YORK CO/BRYNT FD APT, 4 miles from Rock Hill — the closest one on record.
What it actually costs to run, year to year
Electricity use for heating alone comes out to about 2,308 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $588 a year. Rock Hill's gas rate of 16.91 per Mcf, applied to the 29 Mcf a year the furnace burns, puts its running cost near $819 a year, against 16.16¢ per kWh for electricity. Looked at as a full purchase rather than an incremental one, payback here is roughly 58.6 years, leaving the 15-year total $46 behind.
If your home heats with electric baseboard instead of gas
Gas isn't universal in Rock Hill — 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 $880 a year, which recovers the extra $8,000 spent going electric in roughly 9.1 years.
Where Rock Hill ranks in this dataset
Rock Hill lands at position 2003 out of 3206 cities on heating severity (coldest is 1), and 504 out of 3206 by population size (biggest is 1). That's the middle third for winter severity among the cities covered here.
What to do with this number in Rock Hill
About 75,798 people live in Rock Hill, South Carolina, 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 Rock Hill's 3.06 seasonal COP and the rest of this page's numbers get built. Rock Hill's 15.1°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.