Illinois Heating

Heat pump vs furnace in Boone County, Illinois

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Which costs less to run in Boone County?

An outdoor air conditioning condenser unit on a concrete pad beside a dark horizontal-lap sided wall at night, lit by a wall light above, with an electrical disconnect box mounted on the siding.

Heat pump

To heat your home here$2.12per 100,000 Btu

A beige gas furnace with a louvered upper panel stands on a concrete floor against a dark blue wall, with a metal flue pipe and gas and electrical lines running up beside it.

Furnace

To heat your home here$1.33per 100,000 Btu

At Illinois's gas and electricity prices, a gas furnace makes the same heat as a heat pump for at least 37% less.

Btu stands for British thermal unit, the standard measure of heat energy.

Where does a heat pump shine?

  • Heats and cools in one system

    Winter and summer are covered by the same outdoor unit. That's one machine to service instead of two.

    Living room with a white-framed sash window overlooking a green garden, a potted plant and books on a wooden bench below, a navy built-in bookcase at left, and a pale sofa with a navy knit throw and blue table lamp at right.

  • Steady, even comfort

    A heat pump runs long and low instead of blasting on and off. Rooms hold an even temperature all day.

    A dimly lit living room at night with a navy armchair holding an open book and a knitted throw, a lit table lamp, a stone fireplace with a fire, built-in blue shelving, and a golden retriever sleeping on a light rug.

  • No gas line, nothing burning in the house

    A heat pump runs on electricity alone. Nothing burns inside the house.

    A stainless steel kettle sits on a black glass cooktop set into a white speckled countertop above navy blue cabinets, with a wooden cutting board, round marble board, two pepper mills, a mug and a vase of white flowers nearby.

Where does a furnace shine?

  • Strong, steady heat in hard cold

    Winter nights here average 16°F, and that's the kind of cold a furnace just shrugs off. It burns gas to make heat, so the temperature outside doesn't change how warm your house gets.

    A two-story dark blue house with white trim and lit windows at dusk, with snow on the roof and ground and a shoveled path lined with small lanterns leading to the front door.

  • Runs on the gas most homes here already use

    Most homes in Boone County already have gas line in place, since utility gas heats 78.2% of them. If yours is one of them, a gas furnace just hooks into what's already there.

    A row of brick houses with covered porches, blue-painted posts and railings, and metal gas meters, beside a cleared sidewalk bordered by snow and bare trees in low sunlight.

  • Proven, simple, easy to get serviced

    Gas furnaces have heated homes for generations. Almost every HVAC tech knows them inside and out.

    A gloved hand holds a white pleated air filter upright in a basement utility area, with wooden shelving holding storage bins and a basket on the left and furnace ductwork and piping on the right.

What the cold does to a heat pump here

Winter is the long season in Boone County. Heat runs October through May, eight months, against three for cooling. Whatever you install will spend most of its life heating this house, so heating performance is what decides this, not air conditioning.

The overnight low here averages 16°F across December, January and February. That number matters because a standard heat pump starts losing capacity below 40°F and often needs backup heat below about 35°F. Sixteen degrees sits under both marks. So does every one of the roughly 145 nights a year that fall to freezing or below, which is more than half the nights in the heating season. This is not an occasional dip into territory where the heat pump struggles. It is most of an average winter night here.

There are about 14 nights a year that reach 0°F or below. That is the hard edge, and it is a small part of the season, not most of it. A cold-climate heat pump, the kind certified to hold at least 70 percent of its 47°F capacity and still produce 1.75 units of heat per unit of electricity at 5°F, is built for exactly this stretch. Field testing of these units over two winters found backup heat covered only a small share of the output between 0°F and 35°F, and running on backup alone was rare even above 0°F. A standard heat pump, the kind built to the federal minimum, is not tested or rated for that range, and the running cost quoted for one here assumes no backup heat at all. If a heat pump goes into this house, the cold-climate version is the one that holds up on the other 231 nights a year below freezing, not just the 14 coldest.

A row of two-story houses with covered front porches, snow-covered roofs and icicles along a snowy street, with a bare deciduous tree at left under a clear blue sky.

What it costs to run, and what's already there

At Illinois's current fuel prices, a furnace is cheaper to run than a heat pump: $1.33 against $2.12 per 100,000 Btu, both at the federal minimum efficiency for their type. That gap holds for the full eight months heat runs here, not just the cold nights. A cold-climate heat pump narrows it some by making more heat per watt than the minimum, but gas stays the cheaper fuel at these prices either way.

Gas is also what most of this county already has. Utility gas heats 78.2% of homes in Boone County, about four in five. Electricity heats 12.2%, a little over one in ten. If this house already has a gas line and a gas furnace, replacing it with another furnace uses what's already in the walls. Putting in a heat pump means wiring and ductwork sized for electric heat, on top of the unit itself, if that line and that capacity aren't already there. That's worth having a contractor check before deciding.

A furnace only heats. For the other four months of the year here, it has nothing to do, and the house needs a separate air conditioner. A heat pump does both jobs with one system, which is worth something if the alternative is maintaining a furnace all winter and an AC all summer. Where this county's facts come down clearly, it's on cost to run and on what's already in the house to connect to. Both favor the furnace. The case for a heat pump here rests on wanting one system for both seasons, paying more to run it, and making sure it's the cold-climate kind if it has to carry this house through a 16 degree average night.

Sources: NOAA nClimDiv · NOAA 1991–2020 seasonal normals · Census ACS 2020–2024 · EIA SEDS 2024 · 10 CFR 430.32 · PNNL Building America guide · PNNL-37127 field study · ENERGY STAR product criteria

A two-story navy blue house with white trim, a light blue front door and brick chimney, fronted by a snow-covered lawn, cleared walkway, and bare trees under an overcast sky.

Common questions about heat pumps and furnaces

  • Can a heat pump heat a house through an Illinois winter?

    It can, but not alone on the coldest nights here. A standard heat pump puts out less than its rated heat once it drops below 40°F outside, and the overnight low here averages 16°F across December, January and February. Below about 35°F it typically needs backup heat to keep up, and with 145 nights a year at or below freezing, that is more than half the nights the heat runs.

  • Do I need backup heat with a heat pump here?

    Most homeowners here will want it. A standard heat pump's output falls below 40°F and it often needs help below about 35°F, and your winters put you under both marks on most cold nights. A cold climate model holds up better in the teens, but either way you want a plan for the 14 nights a year that hit 0°F or below.

  • Can I keep my furnace and add a heat pump?

    Yes, and here that often makes sense. The two run together: the heat pump carries the heat down to the temperature where it starts to struggle, then the furnace takes over for the rest of the night. Your gas line is probably already there, since utility gas heats about four in five homes in Boone County.

  • Is a heat pump cheaper to run than a furnace in Boone County?

    No, a furnace is cheaper to run here. At Illinois's average prices, a furnace makes the same heat for $1.33 per 100,000 Btu against $2.12 for a heat pump, both built to the federal minimum. Gas is the cheaper fuel in Illinois right now, and that is before counting any backup heat the heat pump needs on cold nights.

A person in dark clothing and a knit cap kneels on a concrete basement floor while working on piping at the top of a gray furnace, with ductwork, insulated walls, and a tool bag nearby.

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