Heat Pump Payback in San Marino, CA
Should San Marino switch to a heat pump?
San Marino sits right on the fence, how long you'll own the house decides this one. $3,000 is what San Marino would pay extra to go electric rather than replace the furnace and AC with the same again. Lower bills claw that back: about $323 saved annually, for a payback of roughly 9.3 years. Whether that's worth it in San Marino depends on how many years you expect to own the place.
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The climate behind San Marino's payback figure
686 heating degree days pile up here every year, so San Marino barely has a winter to speak of; the cooling side runs to 2300 cooling degree days, where summers are hot enough that cooling matters as much as heating. Sizing runs off the design temperature, not the average day: 39.2°F here (coldest 2024 reading 37.4°F), which works out to a seasonal COP of 3.37 for the standard class of unit this climate calls for. A standard ducted system is enough here; San Marino's design temperature doesn't justify the cold-climate premium. These numbers come from El Monte Airport, the closest NOAA station, 5.3 miles out.
What it actually costs to run, year to year
Electricity use for heating alone comes out to about 515 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $813 a year. The gas furnace it replaces burns roughly 7 Mcf a year at $22.01 per Mcf here, for a running cost near $1,136 a year including the old AC (electricity here runs 32.83¢/kWh). If the current system still worked and you replaced it anyway, the full cost would take longer than the 15-year equipment life to earn back; against buying a new furnace and AC regardless, the 15-year total lands $1,842 ahead.
How sensitive San Marino's result is to prices
Because the heat pump's better air conditioning saves more electricity than its heating uses, it stays cheaper to run than the current furnace and AC in San Marino at any electricity price. When quotes arrive, compare the heat pump price with a like-for-like furnace and AC replacement: at $323 a year saved, a difference under $2,261 pays back within 7 years here, and under $3,230 within 10.
The other scenario: no gas furnace to begin with
Plenty of homes in San Marino heat with electricity alone, no gas line involved. 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 $736 a year, which recovers the extra $7,500 spent going electric in roughly 10.2 years.
Where San Marino ranks in this dataset
Among 3206 cities, San Marino's winter puts it at rank 3012 for severity, while its size puts it at rank 2798 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.
Next step if you live in San Marino
About 12,105 people live in San Marino, 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.
Reading further on this page's numbers
Every constant behind this page, the 3.37 seasonal COP, the degree-day corrections, the equipment costs, is documented in the methodology guide. Not every home in San Marino has gas; the guide comparing a heat pump against electric baseboard covers that case separately.