Heat pump running cost in Illinois
In Illinois, a heat pump costs about 84% more to run than a 95% AFUE gas furnace. Against propane, heating oil and electric baseboard the answer is different, and all four are below.
Illinois energy prices, 2025-12, 2026-01, 2026-02
The December 2025 to February 2026 EIA heating season mean, pulled . Every figure on this page is in the CSV and JSON download, published under CC BY 4.0.
| Figure | Value | Source |
|---|---|---|
| Residential electricity | $0.171/kWh | EIA, by state |
| Residential natural gas | $0.98/therm | EIA, by state |
| Propane | $2.11/gal | EIA, PADD 2, Midwest |
| Heating oil | $3.30/gal | EIA, PADD 2, Midwest |
| Electricity to gas price ratio | 5.10 to 1 | derived |
| Breakeven ratio for this equipment | 2.78 to 1 | derived |
| Annual heating degree days | 5,897 | EIA, ENC division |
Illinois ranks 41 of 45 states by electricity to gas price ratio, where 1 is most favourable to a heat pump.
Cost to deliver one kWh of heat in Illinois
| Current system | Fuel price | $ per kWh heat | Heat pump verdict | Difference |
|---|---|---|---|---|
| Natural gas furnace | $0.981/therm | 0.0352 | More expensive to run | 84% |
| Propane furnace | $2.11/gallon | 0.0828 | Cheaper to run | 22% |
| Heating oil furnace or boiler | $3.30/gallon | 0.0981 | Cheaper to run | 34% |
| Electric resistance (baseboard or furnace) | $0.171/kWh | 0.1709 | Cheaper to run | 62% |
| Heat pump, COP 2.64 | $0.171/kWh | 0.0648 |
Assumes a cold climate heat pump at HSPF2 11.0 with 10% of heat from electric resistance backup. Propane and heating oil are published by EIA regionally rather than by state, so those are the nearest regional figures. Change any of it on the calculator.
Rough monthly cost in Illinois
| System | Winter month | Per year |
|---|---|---|
| Gas furnace, 95% AFUE | $140 | $877 |
| Heat pump, effective COP 2.64 | $258 | $1,612 |
An 1,800 sq ft home of typical construction, at 5,897 annual heating degree days for the ENC census division. The square foot coefficient behind this is a rule of thumb rather than a measurement and can be wrong by half in either direction. How this is worked out, and a better method if you have a year of bills.
What this page does not tell you
Running cost only, at state average prices. It excludes equipment and installation cost, rebates, and the fact that a heat pump also replaces an air conditioner. State averages hide large differences between utilities inside Illinois, and this page cannot know your balance point or how much backup heat your system would actually use, which is the input that moves the answer most.
The closest reported households to Illinois
No household in this dataset is in Illinois. The 3 below are in the East North Central census division, which is the group Illinois's heating degree day normal comes from, so the climate assumption behind their figures is the same one used on this page.
| Household | Floor area | kWh | Wh per sq ft per HDD | Worked through in |
|---|---|---|---|---|
| Southwest Indiana 2-ton Daikin Fit ducted, not a cold climate model |
2,160 | 499 January |
0.21 | the fieldwork note |
| Ohio, after the fix 2.5-ton Carrier heat pump, same house |
1,863 | 2,565 January |
1.11 | the three ways backup heat takes over |
| Ohio, before the fix 2.5-ton Carrier heat pump, new build, all electric |
1,863 | 3,500 January |
1.52 | the three ways backup heat takes over |
Watt hours per square foot per heating degree day, which is how this site makes houses of different sizes in different climates comparable. Households with no identified fault sit between 0.53 and 0.92. The full dataset, the method behind that figure, and what was wrong in every household above the band.
A Illinois household would be more use than any of these. If you heat with a heat pump here, a winter month's kWh, your floor area and the month it covers is enough, and it can be sent here. If you want to check your own figure first, the winter bill guide walks through the subtraction.
Where to go from here
Because gas wins on running cost in Illinois, the question worth asking is not whether to switch but whether a dual fuel system beats both, which it usually does, and where its crossover temperature belongs.
If you already have a heat pump and the bill is higher than you expected, start with the four things that make a winter bill run high and how to tell which one is yours. If somebody has told you your usage is insane, the questions people actually ask when the bill arrives covers what that comparison is usually missing.
If you are still choosing, the comparison depends on what you are replacing: a gas furnace, propane, heating oil, or electric baseboards, where the heat pump wins by a wide margin in every state including this one.
And if you want to check the arithmetic rather than take it, every constant and limitation is listed, the data is rebuilt from EIA on a documented schedule, and the things this site has got wrong are published rather than quietly edited.
The reasoning behind these numbers
The verdict at the top of this page turns on one threshold, and that threshold is set by your equipment rather than by your climate, which is the single most misunderstood thing about heat pump running cost. The price it is compared against comes from EIA, averaged across December to February, and using any other window inflates the gas price enough to flip the verdict in fifteen states. This site published that mistake before catching it.