Heat Pump Payback in St. Peters, MO
Heat pump vs. gas furnace in St. Peters, MO
St. Peters technically pencils out, but only past the point the equipment would need replacing anyway. Against a like-for-like gas furnace and AC swap, going electric costs $5,500 more up front here. St. Peters's residents would see roughly $219 a year back in running costs, putting the payback around 25.2 years. St. Peters's own numbers say this pencils out only in theory, not in practice.
Checking a different city
St. Peters is one of 3206 cities covered here, each run through the same model. Search another below.
Why St. Peters's climate drives this number
Degree days tell the story here: St. Peters racks up 3990 heating degree days each year (base 65°F), and summers are hot enough that cooling matters as much as heating, with 1370 cooling degree days on the cooling side. 0°F is the figure equipment gets sized against here, the 99th-percentile cold snap, not an average day, with a low of -8°F in the 2024 station record. Worked through the model, that's a seasonal COP of 2.7 on the cold-climate unit fit for this climate. Below the 25°F line where a standard machine starts leaning on resistance backup, St. Peters sits firmly in cold-climate territory, so that's the class of unit priced here. Source: NOAA station Spirit Of St Louis Airport, 9 miles from St. Peters, the closest one on record.
The yearly running costs in St. Peters
Electricity use for heating alone comes out to about 3,742 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $630 a year. St. Peters's gas rate of $14.94 per Mcf, applied to the 42 Mcf a year the furnace burns, puts the current furnace-and-AC running cost near $849 a year, against 12.83¢ per kWh for electricity. 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 $2,220 behind.
The break-even point in St. Peters
This result holds unless electricity climbs above 19.8¢/kWh (it is 12.83¢ now) or gas drops below $9.68 per Mcf (now $14.94); past either point, gas becomes the cheaper fuel in St. Peters. When quotes arrive, compare the heat pump price with a like-for-like furnace and AC replacement: at $219 a year saved, a difference under $1,533 pays back within 7 years here, and under $2,190 within 10.
The other scenario: no gas furnace to begin with
Gas isn't universal in St. Peters, many houses run on electric heat already. Swap the comparison to resistance heat instead of gas, and St. Peters's answer improves. The saving here runs about $894 a year, which recovers the extra $10,000 spent going electric in roughly 11.2 years.
St. Peters against the rest of the country
Ranked against the other 3206 cities covered, St. Peters comes in at 1512 for heating severity, 1 would be the coldest place in the dataset, and 647 by population, where 1 is largest. That's the middle third for winter severity among the cities covered here.
What to do with this number in St. Peters
About 61,398 people live in St. Peters, Missouri, 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
Every constant behind this page, the 2.7 seasonal COP, the degree-day corrections, the equipment costs, is documented in the methodology guide. St. Peters's 0°F design temperature falls on the cold side of the 25°F cutoff the cold-climate unit guide walks through.