Heat Pump Payback in San Marcos, TX
Should San Marcos switch to a heat pump?
San Marcos sits right on the fence, how long you'll own the house decides this one. $3,000 is what San Marcos would pay extra to go electric rather than replace the furnace and AC with the same again. That premium is recovered through $319 of lower running costs every year, landing the payback clock at roughly 9.4 years. It's a genuine toss-up here, San Marcos's numbers don't point clearly either way.
Compare against another city
San Marcos is one of 3206 cities covered here, each run through the same model. Search another below.
San Marcos's weather, in the numbers that matter
Degree days tell the story here: San Marcos racks up 1168 heating degree days each year (base 65°F), and summers are severe enough that cooling can dominate the annual bill, with 3395 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 26.1°F, and the coldest daily reading in the 2024 station record was 14°F. That puts the seasonal coefficient of performance at 2.98 for the recommended standard unit. San Marcos's winters don't get cold enough to need the cold-climate premium, a standard unit holds up fine. Source: NOAA station San Marcos Municipal Airport, 4.5 miles from San Marcos, the closest one on record.
What it actually costs to run, year to year
Electricity use for heating alone comes out to about 992 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $628 a year. That compares with roughly 12 Mcf a year of gas at San Marcos's $19.42 per-Mcf rate, about $947 a year with the old AC included, against a local electricity rate of 16.15¢/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 $1,786 ahead.
How sensitive San Marcos's result is to prices
In San Marcos the cooling savings outweigh the extra electricity for heating, so no plausible change in the electricity rate would make the old furnace and AC cheaper to run. A useful quote test for San Marcos: the heat pump is worth it within a decade if it costs less than $3,190 more than replacing the furnace and AC, and within 7 years if the gap is under $2,233.
Electric resistance heat in San Marcos, compared
Not every home in San Marcos has gas service. Compared with baseboard or electric-furnace resistance heat, the numbers shift in the heat pump’s favor. The saving here runs about $560 a year, which recovers the extra $7,500 spent going electric in roughly 13.4 years.
San Marcos against the rest of the country
Among 3206 cities, San Marcos's winter puts it at rank 2809 for severity, while its size puts it at rank 519 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 San Marcos
San Marcos, Texas is home to about 74,316 people, and the figures above are the same ones a local HVAC contractor uses to size and quote a system, this site doesn't guess where a real quote would land, it just tells you whether it's worth asking for one. In San Marcos, nothing is lost by holding off until the current equipment genuinely fails.
Ask a local HVAC contractor for a quote before committing either way.
Where San Marcos's figure comes from
The methodology guide walks through exactly how San Marcos's 2.98 seasonal COP and the rest of this page's numbers get built. Homes in San Marcos without gas service should read the electric-resistance comparison instead, the numbers there differ from the gas case above.