Heat Pump Payback in Bay St. Louis, MS
Should Bay St. Louis switch to a heat pump?
In Bay St. Louis, the math is close enough that it comes down to how long you plan to stay. $3,000 is what Bay St. Louis would pay extra to go electric rather than replace the furnace and AC with the same again. That premium is recovered through $324 of lower running costs every year, landing the payback clock at roughly 9.2 years. Whether that's worth it in Bay St. Louis depends on how many years you expect to own the place.
Not the city you meant?
Bay St. Louis is one of 3206 cities covered here, each run through the same model. Search another below.
The climate behind Bay St. Louis's payback figure
Bay St. Louis barely has a winter to speak of, 837 heating degree days a year against a 65°F base, and summers are severe enough that cooling can dominate the annual bill, at 4167 cooling degree days. 29.5°F is the figure equipment gets sized against here, the 99th-percentile cold snap, not an average day, with a low of 20.3°F in the 2024 station record. Worked through the model, that's a seasonal COP of 3.08 on the standard unit fit for this climate. A standard ducted system is enough here; Bay St. Louis's design temperature doesn't justify the cold-climate premium. These numbers come from Bay Waveland Yacht Club, the closest NOAA station, 2.5 miles out.
What it actually costs to run, year to year
Electricity use for heating alone comes out to about 688 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $656 a year. The gas furnace it replaces burns roughly 9 Mcf a year at $16.64 per Mcf here, for a running cost near $980 a year including the old AC (electricity here runs 15.47¢/kWh). Buying outright rather than at replacement time stretches payback to longer than the 15-year equipment life. Over 15 years, compared with a like-for-like replacement, the heat pump leaves you $1,866 ahead.
How sensitive Bay St. Louis'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 Bay St. Louis at any electricity price. When quotes arrive, compare the heat pump price with a like-for-like furnace and AC replacement: at $324 a year saved, a difference under $2,268 pays back within 7 years here, and under $3,240 within 10.
If your home heats with electric baseboard instead of gas
Gas isn't universal in Bay St. Louis, 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. The saving here runs about $507 a year, which recovers the extra $7,500 spent going electric in roughly 14.8 years.
Where Bay St. Louis ranks in this dataset
Bay St. Louis lands at position 2954 out of 3206 cities on heating severity (coldest is 1), and 3085 out of 3206 by population size (biggest is 1). 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 Bay St. Louis
About 10,526 people live in Bay St. Louis, Mississippi, 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
The methodology guide walks through exactly how Bay St. Louis's 3.08 seasonal COP and the rest of this page's numbers get built. Not every home in Bay St. Louis has gas; the guide comparing a heat pump against electric baseboard covers that case separately.