Heat pump vs. gas furnace in Lemont, IL

Lemont is a place where a heat pump genuinely costs more to operate than the alternative. $3,500 is what Lemont 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. Running costs here land $250 a year HIGHER than the furnace it replaces, so that premium is never recovered. That's Lemont's own climate and rates talking, not a hedge or a caveat.

Lemont's weather, in the numbers that matter

4951 heating degree days pile up here every year, so Lemont has a real but manageable winter; the cooling side runs to 1049 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 -4°F, against a record low of -13°F. That puts the seasonal coefficient of performance at 2.6 for the recommended cold-climate unit. Lemont 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, LEWIS UNIVERSITY AIRPORT, 6.8 miles from Lemont.

The month-to-month numbers for Lemont

Modelled on a typical 2000-square-foot house, the heat pump draws about 4,822 kWh a year to keep it warm, plus cooling, for a combined electric bill near $1,090 a year. Lemont's gas rate of 11.25 per Mcf, applied to the 52 Mcf a year the furnace burns, puts its running cost near $839 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 $7,254 behind.

Electric resistance heat in Lemont, compared

Plenty of homes in Lemont 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 $8,000 spent up front comes back in about 5.1 years.

Where Lemont ranks in this dataset

Lemont lands at position 815 out of 3206 cities on heating severity (coldest is 1), and 2072 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.

Deciding what's next in Lemont, IL

Lemont, Illinois is home to about 18,203 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 Lemont, nothing is lost by holding off until the current equipment genuinely fails.

Line up a few local HVAC quotes before you decide.

Where Lemont's figure comes from

Every constant behind this page — the 2.6 seasonal COP, the degree-day corrections, the equipment costs — is documented in the methodology guide. At a -4°F design temperature, Lemont sits in cold-climate territory; the guide to that class of unit explains why.