San Bruno, CA: the heat pump payback math
Here in San Bruno, the honest answer is that a heat pump raises your annual running cost. 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. The heat pump would cost about $30 more a year to run than the furnace it replaces — a premium with no payback. There's no spin on that: San Bruno's numbers say wait.
The climate behind San Bruno's payback figure
2665 heating degree days pile up here every year, so San Bruno has a mild winter by US standards; the cooling side runs to 90 cooling degree days, where summers rarely ask much of an air conditioner. 39.9°F is the figure equipment gets sized against here — the 99th-percentile cold snap, not an average day — with a record low of 35.1°F on file. Worked through the model, that's a seasonal COP of 3.39 on the standard unit fit for this climate. A standard ducted system is enough here; San Bruno's design temperature doesn't justify the cold-climate premium. Source: NOAA station SAN FRANCISCO INTERNATIONAL A, 3.7 miles from San Bruno — the closest one on record.
The month-to-month numbers for San Bruno
Electricity use for heating alone comes out to about 1,991 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $679 a year. That compares with roughly 28 Mcf a year of gas at San Bruno's 22.01 per-Mcf rate — about $649 a year — against a local electricity rate of 32.83¢/kWh. Looked at as a full purchase rather than an incremental one, payback here is longer than the 15-year equipment life, leaving the 15-year total $1,443 behind.
If your home heats with electric baseboard instead of gas
Gas isn't universal in San Bruno — 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. About $1,575 a year comes back this way, enough that the 3.5-year payback clears the $5,500 premium comfortably within the equipment's life.
How San Bruno compares nationally
Among 3206 cities, San Bruno's winter puts it at rank 2059 for severity, while its size puts it at rank 977 for population — 1 in both cases being the extreme. That's the middle third for winter severity among the cities covered here.
Next step for 42,035 people in San Bruno
About 42,035 people live in San Bruno, 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.
Line up a few local HVAC quotes before you decide.
More on how this number was built
Nothing above is a black box: the methodology guide shows the full arithmetic behind San Bruno's 3.39 seasonal COP and payback figure. The guide on cities that never pay back covers exactly San Bruno's situation: a genuinely higher annual running cost, not a slow one.