Is a heat pump worth it in Franklin?
Franklin technically pencils out, but only past the point the equipment would need replacing anyway. $3,500 is what Franklin 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. Franklin's residents would see roughly $134 a year back in running costs, putting the payback around 26.2 years. Franklin's own numbers say this pencils out only in theory, not in practice.
The climate behind Franklin's payback figure
Degree days tell the story here: Franklin racks up 2670 heating degree days each year (base 65°F), and summers are hot enough that cooling matters as much as heating, with 2133 cooling degree days on the cooling side. Sizing runs off the design temperature, not the average day: 7°F here (record low -0.9°F), which works out to a seasonal COP of 2.87 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, Franklin sits firmly in cold-climate territory, so that's the class of unit priced here. Source: NOAA station NASHVILLE INTERNATIONAL AIRPO, 16.8 miles from Franklin — the closest one on record.
What it actually costs to run, year to year
Modelled on a typical 2000-square-foot house, the heat pump draws about 2,356 kWh a year to keep it warm, plus cooling, for a combined electric bill near $579 a year. Franklin's gas rate of 11.84 per Mcf, applied to the 28 Mcf a year the furnace burns, puts its running cost near $713 a year, against 13.87¢ per kWh for electricity. Looked at as a full purchase rather than an incremental one, payback here is roughly 101 years, leaving the 15-year total $1,495 behind.
The other scenario: no gas furnace to begin with
Gas isn't universal in Franklin — many houses run on electric heat already. Against electric-resistance heat — baseboard or an electric furnace, both 100% efficient but still just resistance — the case for switching gets stronger here. The saving here runs about $742 a year, which recovers the extra $8,000 spent going electric in roughly 10.8 years.
Where Franklin ranks in this dataset
Franklin lands at position 2051 out of 3206 cities on heating severity (coldest is 1), and 400 out of 3206 by population size (biggest is 1). That's the middle third for winter severity among the cities covered here.
Deciding what's next in Franklin, TN
About 89,142 people live in Franklin, 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.
Get quotes from local HVAC contractors before deciding.
More on how this number was built
Nothing above is a black box: the methodology guide shows the full arithmetic behind Franklin's 2.87 seasonal COP and payback figure. At a 7°F design temperature, Franklin sits in cold-climate territory; the guide to that class of unit explains why.