Heat pump vs. gas furnace in San Francisco, CA
Here in San Francisco, the honest answer is that a heat pump raises your annual running cost. $1,000 is what San Francisco 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. The heat pump would cost about $21 more a year to run than the furnace it replaces — a premium with no payback. There's no spin on that: San Francisco's numbers say wait.
Why San Francisco's climate drives this number
Degree days tell the story here: San Francisco racks up 3372 heating degree days each year (base 65°F), and summers rarely ask much of an air conditioner, with 29 cooling degree days on the cooling side. The 99% winter design temperature here — the cold snap equipment must be sized for, not the seasonal average — is 43.9°F, against a record low of 42.4°F. That puts the seasonal coefficient of performance at 3.51 for the recommended standard unit. A standard ducted system is enough here; San Francisco's design temperature doesn't justify the cold-climate premium. Source: NOAA station SAN FRANCISCO, 31.5 miles from San Francisco — the closest one on record.
What it actually costs to run, year to year
A 2000-square-foot house here would pull roughly 2,433 heating kilowatt-hours annually on top of cooling, totalling about $807 a year on electricity. That compares with roughly 35 Mcf a year of gas at San Francisco's 22.01 per-Mcf rate — about $785 a year — against a local electricity rate of 32.83¢/kWh. Buy it outright, not incrementally, and payback stretches to beyond the 15-year equipment life; over 15 years the net position sits $1,322 behind.
The other scenario: no gas furnace to begin with
Gas isn't universal in San Francisco — many houses run on electric heat already. Compared with baseboard or electric-furnace resistance heat, the numbers shift in the heat pump’s favor. About $2,009 a year comes back this way, enough that the 2.7-year payback clears the $5,500 premium comfortably within the equipment's life.
San Francisco against the rest of the country
Ranked against the other 3206 cities covered, San Francisco comes in at 1813 for heating severity — 1 would be the coldest place in the dataset — and 17 by population, where 1 is largest. That's the middle third for winter severity among the cities covered here.
Deciding what's next in San Francisco, CA
About 827,526 people live in San Francisco, 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.
Ask a local HVAC contractor for a quote before committing either way.
Reading further on this page's numbers
The methodology guide walks through exactly how San Francisco's 3.51 seasonal COP and the rest of this page's numbers get built. The guide on cities that never pay back covers exactly San Francisco's situation: a genuinely higher annual running cost, not a slow one.