Maryville, TN: the heat pump payback math
Maryville 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). Lower bills claw that back: about $102 saved annually, for a payback of roughly 34.2 years. Maryville's own numbers say this pencils out only in theory, not in practice.
The climate behind Maryville's payback figure
2992 heating degree days pile up here every year, so Maryville has a mild winter by US standards; the cooling side runs to 1659 cooling degree days, where summers are hot enough that cooling matters as much as heating. Sizing runs off the design temperature, not the average day: 6.1°F here (record low 0°F), which works out to a seasonal COP of 2.85 for the cold-climate class of unit this climate calls for. Below the 25°F line where a standard machine starts leaning on resistance backup, Maryville sits firmly in cold-climate territory, so that's the class of unit priced here. These numbers come from MC GHEE TYSON AIRPORT, the closest NOAA station, 4.9 miles out.
The month-to-month numbers for Maryville
Modelled on a typical 2000-square-foot house, the heat pump draws about 2,658 kWh a year to keep it warm, plus cooling, for a combined electric bill near $565 a year. The gas furnace it replaces burns roughly 31 Mcf a year at 11.84 per Mcf here, for a running cost near $667 a year (electricity here runs 13.87¢/kWh). Priced as a standalone purchase rather than against a like-for-like replacement, equipment payback runs about 132 years, for a 15-year net position $1,966 behind.
The other scenario: no gas furnace to begin with
Gas isn't universal in Maryville — many houses run on electric heat already. Swap the comparison to resistance heat instead of gas, and Maryville's answer improves. Switching saves about $784 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 10.2 years.
How Maryville compares nationally
Among 3206 cities, Maryville's winter puts it at rank 1936 for severity, while its size puts it at rank 1266 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 Maryville
About 32,373 people live in Maryville, Tennessee, 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
The methodology guide walks through exactly how Maryville's 2.85 seasonal COP and the rest of this page's numbers get built. Maryville's 6.1°F design temperature is below the 25°F line, which is why a cold-climate unit is the right call here — see what that changes in the cold-climate unit guide.