San Diego, CA: the heat pump payback math
San Diego sits right on the fence — how long you'll own the house decides this one. Swap a failed furnace and AC for a heat pump rather than buying like-for-like, and the extra cost here runs $1,000 after a $2,000 federal tax credit. That premium is recovered through $70 of lower running costs every year, landing the payback clock at roughly 14.3 years. Whether that's worth it in San Diego depends on how many years you expect to own the place.
The climate behind San Diego's payback figure
1529 heating degree days pile up here every year, so San Diego has a mild winter by US standards; the cooling side runs to 694 cooling degree days, where summers add a moderate cooling load. Sizing runs off the design temperature, not the average day: 37.9°F here (record low 35.1°F), which works out to a seasonal COP of 3.33 for the standard class of unit this climate calls for. A standard ducted system is enough here; San Diego's design temperature doesn't justify the cold-climate premium. Source: NOAA station MONTGOMERY FIELD AIRPORT, 1.4 miles from San Diego — the closest one on record.
What it actually costs to run, year to year
A 2000-square-foot house here would pull roughly 1,163 heating kilowatt-hours annually on top of cooling, totalling about $576 a year on electricity. The gas furnace it replaces burns roughly 16 Mcf a year at 22.01 per Mcf here, for a running cost near $646 a year (electricity here runs 32.83¢/kWh). Buy it outright, not incrementally, and payback stretches to 157.6 years; over 15 years the net position sits $47 ahead.
Electric resistance heat in San Diego, compared
Plenty of homes in San Diego heat with electricity alone, no gas line involved. Swap the comparison to resistance heat instead of gas, and San Diego's answer improves. About $990 a year comes back this way, enough that the 5.6-year payback clears the $5,500 premium comfortably within the equipment's life.
Where San Diego ranks in this dataset
Ranked against the other 3206 cities covered, San Diego comes in at 2675 for heating severity — 1 would be the coldest place in the dataset — and 8 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.
Next step for 1,404,452 people in San Diego
About 1,404,452 people live in San Diego, 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, 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 San Diego's figure comes from
The methodology guide walks through exactly how San Diego's 3.33 seasonal COP and the rest of this page's numbers get built. Not every home in San Diego has gas; the guide comparing a heat pump against electric baseboard covers that case separately.