Troy, IL: the heat pump payback math
In Troy, a heat pump would cost more to run each year than what you have now. 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). Unfortunately the electric bill outweighs the gas bill it replaces by about $74 a year here, so the extra spend stays unrecovered. There's no spin on that: Troy's numbers say wait.
The climate behind Troy's payback figure
Degree days tell the story here: Troy racks up 3677 heating degree days each year (base 65°F), and summers are hot enough that cooling matters as much as heating, with 1640 cooling degree days on the cooling side. The 99% winter design temperature here — the cold snap equipment must be sized for, not the seasonal average — is 2.5°F, against a record low of -3.8°F. That puts the seasonal coefficient of performance at 2.76 for the recommended cold-climate unit. Below the 25°F line where a standard machine starts leaning on resistance backup, Troy sits firmly in cold-climate territory, so that's the class of unit priced here. Climate figures trace to the nearest NOAA station, SCOTT AIR FORCE BASE/MIDAMERI, 12.4 miles from Troy.
Troy's running-cost comparison, in dollars
Electricity use for heating alone comes out to about 3,373 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $909 a year. Troy's gas rate of 11.25 per Mcf, applied to the 38 Mcf a year the furnace burns, puts its running cost near $836 a year, against 19.06¢ per kWh for electricity. Looked at as a full purchase rather than an incremental one, payback here is longer than the 15-year equipment life, leaving the 15-year total $4,604 behind.
If your home heats with electric baseboard instead of gas
Gas isn't universal in Troy — many houses run on electric heat already. Swap the comparison to resistance heat instead of gas, and Troy's answer improves. The saving here runs about $1,270 a year, which recovers the extra $8,000 spent going electric in roughly 6.3 years.
How Troy compares nationally
Among 3206 cities, Troy's winter puts it at rank 1700 for severity, while its size puts it at rank 2839 for population — 1 in both cases being the extreme. That's the middle third for winter severity among the cities covered here.
Deciding what's next in Troy, IL
About 11,810 people live in Troy, Illinois, 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.
Reading further on this page's numbers
The methodology guide walks through exactly how Troy's 2.76 seasonal COP and the rest of this page's numbers get built. Troy's 2.5°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.