Columbia, TN: the heat pump payback math
The payback math works in Columbia on paper, past the equipment's own working life. 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). Columbia's residents would see roughly $95 a year back in running costs, putting the payback around 36.6 years. That's a technicality, not a recommendation, for anyone actually living in Columbia.
Columbia's weather, in the numbers that matter
3098 heating degree days pile up here every year, so Columbia has a real but manageable winter; the cooling side runs to 1615 cooling degree days, where summers are hot enough that cooling matters as much as heating. The 99% winter design temperature here — the cold snap equipment must be sized for, not the seasonal average — is 5°F, against a record low of -13°F. That puts the seasonal coefficient of performance at 2.82 for the recommended cold-climate unit. Columbia 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. Climate figures trace to the nearest NOAA station, ELLINGTON, 15.8 miles from Columbia.
What it actually costs to run, year to year
Electricity use for heating alone comes out to about 2,782 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $577 a year. The gas furnace it replaces burns roughly 32 Mcf a year at 11.84 per Mcf here, for a running cost near $672 a year (electricity here runs 13.87¢/kWh). Looked at as a full purchase rather than an incremental one, payback here is roughly 141.4 years, leaving the 15-year total $2,068 behind.
The other scenario: no gas furnace to begin with
Plenty of homes in Columbia heat with electricity alone, no gas line involved. Swap the comparison to resistance heat instead of gas, and Columbia's answer improves. The saving here runs about $802 a year, which recovers the extra $8,000 spent going electric in roughly 10 years.
Columbia against the rest of the country
Columbia lands at position 1878 out of 3206 cities on heating severity (coldest is 1), and 839 out of 3206 by population size (biggest is 1). That's the middle third for winter severity among the cities covered here.
Next step for 48,812 people in Columbia
Columbia, Tennessee is home to about 48,812 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 Columbia, nothing is lost by holding off until the current equipment genuinely fails.
Line up a few local HVAC quotes before you decide.
More on how this number was built
Nothing above is a black box: the methodology guide shows the full arithmetic behind Columbia's 2.82 seasonal COP and payback figure. Columbia's 5°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.