Deerfield, IL: the heat pump payback math
In Deerfield, a heat pump would cost more to run each year than what you have now. Swap a failed furnace and AC for a heat pump rather than buying like-for-like, and the extra cost here runs $3,500 after a $2,000 federal 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: Deerfield's numbers say wait.
The climate behind Deerfield's payback figure
Deerfield has a real but manageable winter — 4991 heating degree days a year against a 65°F base — and summers are hot enough that cooling matters as much as heating, at 1020 cooling degree days. 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. Deerfield 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. These numbers come from PALWAUKEE MUNICIPAL ARPT, the closest NOAA station, 4.1 miles out.
Deerfield's running-cost comparison, in dollars
Electricity use for heating alone comes out to about 4,716 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $1,065 a year. The gas furnace it replaces burns roughly 52 Mcf a year at 11.25 per Mcf here, for a running cost near $837 a year (electricity here runs 19.06¢/kWh). Priced as a standalone purchase rather than against a like-for-like replacement, equipment payback runs past the 15-year equipment life, for a 15-year net position $6,917 behind.
Electric resistance heat in Deerfield, compared
Plenty of homes in Deerfield heat with electricity alone, no gas line involved. Compared with baseboard or electric-furnace resistance heat, the numbers shift in the heat pump’s favor. About $1,596 a year comes back this way, enough that the 5-year payback clears the $8,000 premium comfortably within the equipment's life.
How Deerfield compares nationally
Ranked against the other 3206 cities covered, Deerfield comes in at 728 for heating severity — 1 would be the coldest place in the dataset — and 2001 by population, where 1 is largest. 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 Deerfield
About 19,138 people live in Deerfield, 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.
Line up a few local HVAC quotes before you decide.
Reading further on this page's numbers
Every constant behind this page — the 2.68 seasonal COP, the degree-day corrections, the equipment costs — is documented in the methodology guide. At a -0.9°F design temperature, Deerfield sits in cold-climate territory; the guide to that class of unit explains why.