Heat Pump Payback in Darien, IL
Heat pump vs. gas furnace in Darien, IL
Darien is a place where a heat pump genuinely costs more to operate than the alternative. $5,500 is what Darien would pay extra to go electric rather than replace the furnace and AC with the same again. Running costs here land $250 a year higher than the furnace it replaces, so that premium is never recovered. That's Darien's own climate and rates talking, not a hedge or a caveat.
Checking a different city
This runs the same numbers for 3206 US cities, not just Darien. Look one up here.
Darien's weather, in the numbers that matter
Darien has a real but manageable winter, 4951 heating degree days a year against a 65°F base, and summers are hot enough that cooling matters as much as heating, at 1049 cooling degree days. The 99% winter design temperature here, the cold snap equipment must be sized for, not the seasonal average, is -4°F, and the coldest daily reading in the 2024 station record was -13°F. That puts the seasonal coefficient of performance at 2.6 for the recommended cold-climate unit. Below the 25°F line where a standard machine starts leaning on resistance backup, Darien sits firmly in cold-climate territory, so that's the class of unit priced here. Climate figures trace to the nearest NOAA station, Lewis University Airport, 11.2 miles from Darien.
The yearly running costs in Darien
Electricity use for heating alone comes out to about 4,822 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $1,090 a year. Darien's gas rate of $11.25 per Mcf, applied to the 52 Mcf a year the furnace burns, puts the current furnace-and-AC running cost near $839 a year, against 19.06¢ per kWh for electricity. Because the heat pump costs more to run here, the gap only widens with time: $9,254 behind after 15 years compared with replacing the furnace and AC like-for-like.
The break-even point in Darien
For the verdict in Darien to flip, electricity would need to drop to about 13.3¢/kWh from 19.06¢, or gas climb past $16.10 per Mcf from $11.25. A utility offering a lower heat pump rate can change this. Until then, no quote price makes a heat pump pay back against gas in Darien; the case for one here rests on comfort, cooling, or replacing electric heat instead.
The other scenario: no gas furnace to begin with
Plenty of homes in Darien heat with electricity alone, no gas line involved. Against electric-resistance heat, baseboard or an electric furnace, both 100% efficient but still just resistance, the case for switching gets stronger here. Switching saves about $1,559 a year here, a heat pump moving heat rather than generating it needs far less electricity than resistance coils, so the extra $10,000 spent up front comes back in about 6.4 years.
Darien against the rest of the country
Darien lands at position 811 out of 3206 cities on heating severity (coldest is 1), and 1781 out of 3206 by population size (biggest is 1). That's the coldest third of the dataset, where climate does most of the work behind this figure.
What to do with this number in Darien
Darien, Illinois is home to about 22,015 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 Darien, 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 Darien's 2.6 seasonal COP and payback figure. Darien's -4°F design temperature falls on the cold side of the 25°F cutoff the cold-climate unit guide walks through.