Spartanburg, SC: the heat pump payback math
The payback math works in Spartanburg on paper, past the equipment's own working life. $3,500 is what Spartanburg 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 $207 of lower running costs every year, landing the payback clock at roughly 16.9 years. Spartanburg's own numbers say this pencils out only in theory, not in practice.
The climate behind Spartanburg's payback figure
2098 heating degree days pile up here every year, so Spartanburg has a mild winter by US standards; the cooling side runs to 1461 cooling degree days, where summers are hot enough that cooling matters as much as heating. The 99% winter design temperature here — the cold snap equipment must be sized for, not the seasonal average — is 21.2°F, against a record low of 10.4°F. That puts the seasonal coefficient of performance at 3.21 for the recommended cold-climate unit. Spartanburg 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. These numbers come from SPARTANBURG, the closest NOAA station, 2.4 miles out.
What it actually costs to run, year to year
Electricity use for heating alone comes out to about 1,655 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $469 a year. The gas furnace it replaces burns roughly 22 Mcf a year at 16.91 per Mcf here, for a running cost near $675 a year (electricity here runs 16.16¢/kWh). Priced as a standalone purchase rather than against a like-for-like replacement, equipment payback runs about 65.3 years, for a 15-year net position $399 behind.
The other scenario: no gas furnace to begin with
Not every home in Spartanburg has gas service. Swap the comparison to resistance heat instead of gas, and Spartanburg's answer improves. The saving here runs about $696 a year, which recovers the extra $8,000 spent going electric in roughly 11.5 years.
Spartanburg against the rest of the country
Among 3206 cities, Spartanburg's winter puts it at rank 2380 for severity, while its size puts it at rank 1043 for population — 1 in both cases being the extreme. That's the mildest third of cities covered, where utility rates carry more of the answer than climate does.
Next step for 39,606 people in Spartanburg
About 39,606 people live in Spartanburg, 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.
Where Spartanburg's figure comes from
Every constant behind this page — the 3.21 seasonal COP, the degree-day corrections, the equipment costs — is documented in the methodology guide. Spartanburg's 21.2°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.