Heat pump vs. gas furnace in Clayton, MO
This one's marginal in Clayton: it only clears if you stay long enough. $3,500 is what Clayton 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 $242 of lower running costs every year, landing the payback clock at roughly 14.5 years. It's a genuine toss-up here — Clayton's numbers don't point clearly either way.
How cold Clayton actually gets
Degree days tell the story here: Clayton racks up 3396 heating degree days each year (base 65°F), and summers are hot enough that cooling matters as much as heating, with 2013 cooling degree days on the cooling side. Sizing runs off the design temperature, not the average day: 1.9°F here (record low -7.1°F), which works out to a seasonal COP of 2.75 for the cold-climate class of unit this climate calls for. A cold-climate unit is the right call in Clayton — below 25°F design temperature, a standard heat pump leans hard on electric-resistance backup, which erases most of the savings. Climate figures trace to the nearest NOAA station, LAMBERT-ST LOUIS INTERNATIONA, 7.9 miles from Clayton.
Clayton's running-cost comparison, in dollars
Modelled on a typical 2000-square-foot house, the heat pump draws about 3,127 kWh a year to keep it warm, plus cooling, for a combined electric bill near $621 a year. That compares with roughly 35 Mcf a year of gas at Clayton's 14.94 per-Mcf rate — about $863 a year — against a local electricity rate of 12.83¢/kWh. Priced as a standalone purchase rather than against a like-for-like replacement, equipment payback runs about 55.8 years, for a 15-year net position $126 ahead.
The other scenario: no gas furnace to begin with
Not every home in Clayton has gas service. Against electric-resistance heat — baseboard or an electric furnace, both 100% efficient but still just resistance — the case for switching gets stronger here. Switching saves about $817 a year here — a heat pump moving heat rather than generating it needs far less electricity than resistance coils — so the extra $8,000 spent up front comes back in about 9.8 years.
Clayton against the rest of the country
Among 3206 cities, Clayton's winter puts it at rank 1801 for severity, while its size puts it at rank 2137 for population — 1 in both cases being the extreme. That's the middle third for winter severity among the cities covered here.
What to do with this number in Clayton
Clayton, Missouri is home to about 17,512 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 Clayton, 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 Clayton's figure comes from
The methodology guide walks through exactly how Clayton's 2.75 seasonal COP and the rest of this page's numbers get built. At a 1.9°F design temperature, Clayton sits in cold-climate territory; the guide to that class of unit explains why.