Mount Prospect, IL: the heat pump payback math
Here in Mount Prospect, the honest answer is that a heat pump raises your annual running cost. 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). Running costs here land $228 a year HIGHER than the furnace it replaces, so that premium is never recovered. There's no spin on that: Mount Prospect's numbers say wait.
Why Mount Prospect's climate drives this number
4991 heating degree days pile up here every year, so Mount Prospect has a real but manageable winter; the cooling side runs to 1020 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 -0.9°F, against a record low of -11°F. That puts the seasonal coefficient of performance at 2.68 for the recommended cold-climate unit. Below the 25°F line where a standard machine starts leaning on resistance backup, Mount Prospect sits firmly in cold-climate territory, so that's the class of unit priced here. Climate figures trace to the nearest NOAA station, PALWAUKEE MUNICIPAL ARPT, 4.3 miles from Mount Prospect.
Mount Prospect's running-cost comparison, in dollars
Modelled on a typical 2000-square-foot house, the heat pump draws about 4,716 kWh a year to keep it warm, plus cooling, for a combined electric bill near $1,065 a year. Mount Prospect's gas rate of 11.25 per Mcf, applied to the 52 Mcf a year the furnace burns, puts its running cost near $837 a year, against 19.06¢ per kWh for electricity. Buy it outright, not incrementally, and payback stretches to beyond the 15-year equipment life; over 15 years the net position sits $6,917 behind.
The other scenario: no gas furnace to begin with
Plenty of homes in Mount Prospect 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. The saving here runs about $1,596 a year, which recovers the extra $8,000 spent going electric in roughly 5 years.
Where Mount Prospect ranks in this dataset
Mount Prospect lands at position 714 out of 3206 cities on heating severity (coldest is 1), and 740 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 Mount Prospect, IL
About 55,460 people live in Mount Prospect, 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.
More on how this number was built
Nothing above is a black box: the methodology guide shows the full arithmetic behind Mount Prospect's 2.68 seasonal COP and payback figure. Mount Prospect's -0.9°F design temperature falls on the cold side of the 25°F cutoff the cold-climate unit guide walks through.