Jennings, MO: the heat pump payback math
In Jennings, the math is close enough that it comes down to how long you plan to stay. Swap a failed furnace and AC for a heat pump rather than buying like-for-like, and the extra cost here runs $3,500 after a $2,000 federal tax credit. Lower bills claw that back: about $242 saved annually, for a payback of roughly 14.5 years. It's a genuine toss-up here — Jennings's numbers don't point clearly either way.
How cold Jennings actually gets
Jennings has a real but manageable winter — 3396 heating degree days a year against a 65°F base — and summers are hot enough that cooling matters as much as heating, at 2013 cooling degree days. 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. Jennings needs the cold-climate class of unit: past a 25°F design temperature a standard heat pump falls back on resistance backup often enough to eat the savings. These numbers come from LAMBERT-ST LOUIS INTERNATIONA, the closest NOAA station, 6.3 miles out.
Jennings'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. The gas furnace it replaces burns roughly 35 Mcf a year at 14.94 per Mcf here, for a running cost near $863 a year (electricity here runs 12.83¢/kWh). Looked at as a full purchase rather than an incremental one, payback here is roughly 55.8 years, leaving the 15-year total $126 ahead.
If your home heats with electric baseboard instead of gas
Not every home in Jennings has gas service. Swap the comparison to resistance heat instead of gas, and Jennings's answer improves. About $817 a year comes back this way, enough that the 9.8-year payback clears the $8,000 premium comfortably within the equipment's life.
Jennings against the rest of the country
Among 3206 cities, Jennings's winter puts it at rank 1803 for severity, while its size puts it at rank 2651 for population — 1 in both cases being the extreme. That's the middle third for winter severity among the cities covered here.
Next step for 13,024 people in Jennings
Jennings, Missouri is home to about 13,024 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 Jennings, nothing is lost by holding off until the current equipment genuinely fails.
Line up a few local HVAC quotes before you decide.
Where Jennings's figure comes from
The methodology guide walks through exactly how Jennings's 2.75 seasonal COP and the rest of this page's numbers get built. At a 1.9°F design temperature, Jennings sits in cold-climate territory; the guide to that class of unit explains why.