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 $3,500 more up front here (already netting out a $2,000 tax credit). St. Peters's residents would see roughly $219 a year back in running costs, putting the payback around 16 years. St. Peters's own numbers say this pencils out only in theory, not in practice.
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 record low of -8°F on file. 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 month-to-month numbers for 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 its running cost near $849 a year, against 12.83¢ per kWh for electricity. Buy it outright, not incrementally, and payback stretches to 61.7 years; over 15 years the net position sits $220 behind.
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 $8,000 spent going electric in roughly 8.9 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.