Should Bay St. Louis switch to a heat pump?
In Bay St. Louis, a heat pump pays for itself within a reasonable window. $1,000 is what Bay St. Louis 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. That premium is recovered through $324 of lower running costs every year, landing the payback clock at roughly 3.1 years. That's a real payback, built from Bay St. Louis's own climate and utility rates, not a national guess.
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 record low of 20.3°F on file. 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 (electricity here runs 15.47¢/kWh). Buy it outright, not incrementally, and payback stretches to 33.9 years; over 15 years the net position sits $3,866 ahead.
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 $5,500 spent going electric in roughly 10.8 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 for 10,526 people 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, it's worth getting quotes before your current system fails, not after.
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. See what Bay St. Louis's figure looks like without the $2,000 federal credit in the guide to how that credit moves the payback window.