Heat pump vs. gas furnace in Hartsville/Trousdale County, TN
Hartsville/Trousdale County technically pencils out, but only past the point the equipment would need replacing anyway. 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. That premium is recovered through $108 of lower running costs every year, landing the payback clock at roughly 32.5 years. Hartsville/Trousdale County's own numbers say this pencils out only in theory, not in practice.
The climate behind Hartsville/Trousdale County's payback figure
Degree days tell the story here: Hartsville/Trousdale County racks up 3001 heating degree days each year (base 65°F), and summers are hot enough that cooling matters as much as heating, with 1705 cooling degree days on the cooling side. 7°F is the figure equipment gets sized against here — the 99th-percentile cold snap, not an average day — with a record low of -7.6°F on file. Worked through the model, that's a seasonal COP of 2.87 on the cold-climate unit fit for this climate. Below the 25°F line where a standard machine starts leaning on resistance backup, Hartsville/Trousdale County sits firmly in cold-climate territory, so that's the class of unit priced here. Source: NOAA station SMYRNA AIRPORT, 33.4 miles from Hartsville/Trousdale County — the closest one on record.
What it actually costs to run, year to year
A 2000-square-foot house here would pull roughly 2,648 heating kilowatt-hours annually on top of cooling, totalling about $569 a year on electricity. The gas furnace it replaces burns roughly 31 Mcf a year at 11.84 per Mcf here, for a running cost near $677 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 125.4 years, for a 15-year net position $1,885 behind.
The other scenario: no gas furnace to begin with
Not every home in Hartsville/Trousdale County has gas service. Swap the comparison to resistance heat instead of gas, and Hartsville/Trousdale County's answer improves. The saving here runs about $792 a year, which recovers the extra $8,000 spent going electric in roughly 10.1 years.
Hartsville/Trousdale County against the rest of the country
Hartsville/Trousdale County lands at position 1934 out of 3206 cities on heating severity (coldest is 1), and 2787 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 Hartsville/Trousdale County, TN
About 12,159 people live in Hartsville/Trousdale County, 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.
Ask a local HVAC contractor for a quote before committing either way.
More on how this number was built
The methodology guide walks through exactly how Hartsville/Trousdale County's 2.87 seasonal COP and the rest of this page's numbers get built. At a 7°F design temperature, Hartsville/Trousdale County sits in cold-climate territory; the guide to that class of unit explains why.