Walnut, CA: the heat pump payback math
In Walnut, a heat pump pays for itself within a reasonable window. $1,000 is what Walnut 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. Walnut's residents would see roughly $251 a year back in running costs, putting the payback around 4 years. That's a real payback, built from Walnut's own climate and utility rates, not a national guess.
Why Walnut's climate drives this number
1219 heating degree days pile up here every year, so Walnut barely has a winter to speak of; the cooling side runs to 1906 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 37.4°F, against a record low of 35.6°F. That puts the seasonal coefficient of performance at 3.31 for the recommended standard unit. A standard ducted system is enough here; Walnut's design temperature doesn't justify the cold-climate premium. Source: NOAA station BRACKETT FIELD AIRPORT, 6 miles from Walnut — the closest one on record.
What it actually costs to run, year to year
A 2000-square-foot house here would pull roughly 933 heating kilowatt-hours annually on top of cooling, totalling about $840 a year on electricity. That compares with roughly 13 Mcf a year of gas at Walnut's 22.01 per-Mcf rate — about $1,090 a year — against a local electricity rate of 32.83¢/kWh. Priced as a standalone purchase rather than against a like-for-like replacement, equipment payback runs about 43.9 years, for a 15-year net position $2,761 ahead.
If your home heats with electric baseboard instead of gas
Gas isn't universal in Walnut — 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. Switching saves about $985 a year here — a heat pump moving heat rather than generating it needs far less electricity than resistance coils — so the extra $5,500 spent up front comes back in about 5.6 years.
Where Walnut ranks in this dataset
Among 3206 cities, Walnut's winter puts it at rank 2794 for severity, while its size puts it at rank 1464 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.
What to do with this number in Walnut
About 27,250 people live in Walnut, California, 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, it's worth getting quotes before your current system fails, not after.
Get quotes from local HVAC contractors before deciding.
More on how this number was built
Every constant behind this page — the 3.31 seasonal COP, the degree-day corrections, the equipment costs — is documented in the methodology guide. See what Walnut's figure looks like without the $2,000 federal credit in the guide to how that credit moves the payback window.