Wilmington, DE: the heat pump payback math
Wilmington technically pencils out, but only past the point the equipment would need replacing anyway. Swap a failed furnace and AC for a heat pump rather than buying like-for-like, and the extra cost here runs $3,500 after a $2,000 federal tax credit. Wilmington's residents would see roughly $164 a year back in running costs, putting the payback around 21.4 years. Wilmington's own numbers say this pencils out only in theory, not in practice.
Why Wilmington's climate drives this number
Wilmington has a real but manageable winter — 4086 heating degree days a year against a 65°F base — and summers are hot enough that cooling matters as much as heating, at 1272 cooling degree days. The 99% winter design temperature here — the cold snap equipment must be sized for, not the seasonal average — is 10°F, against a record low of 9°F. That puts the seasonal coefficient of performance at 2.94 for the recommended cold-climate unit. Wilmington 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 NEW CASTLE COUNTY AIRPORT, 5.8 miles from Wilmington — the closest one on record.
Wilmington's running-cost comparison, in dollars
A 2000-square-foot house here would pull roughly 3,519 heating kilowatt-hours annually on top of cooling, totalling about $803 a year on electricity. That compares with roughly 43 Mcf a year of gas at Wilmington's 15.97 per-Mcf rate — about $967 a year — against a local electricity rate of 17.45¢/kWh. Buy it outright, not incrementally, and payback stretches to 82.4 years; over 15 years the net position sits $1,041 behind.
The other scenario: no gas furnace to begin with
Gas isn't universal in Wilmington — many houses run on electric heat already. 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 $1,290 a year, which recovers the extra $8,000 spent going electric in roughly 6.2 years.
Wilmington against the rest of the country
Ranked against the other 3206 cities covered, Wilmington comes in at 1460 for heating severity — 1 would be the coldest place in the dataset — and 526 by population, where 1 is largest. That's the middle third for winter severity among the cities covered here.
Deciding what's next in Wilmington, DE
About 73,176 people live in Wilmington, Delaware, 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 Wilmington's figure comes from
The methodology guide walks through exactly how Wilmington's 2.94 seasonal COP and the rest of this page's numbers get built. Wilmington'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.