Illinois Heating

Heat pump vs furnace in Kendall County, Illinois

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Pros who work in Kendall County

Which costs less to run in Kendall County?

An outdoor air conditioning condenser unit with a top-mounted fan grille sits on a concrete pad surrounded by gravel, in front of dark horizontal lap siding with a wall-mounted disconnect box and conduit.

Heat pump

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

A beige sheet-metal furnace with louvered vent panels and side gas piping stands in a basement corner against dark blue painted walls, with a galvanized flue pipe rising to the ceiling and a bare light bulb overhead.

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

    A heat pump runs the same way all year. It pulls heat into the house in winter and pushes it out in summer.

    A living room with a beige sofa holding navy and light blue cushions and a fringed knit throw, beside a window overlooking a green garden, with a dark blue built-in bookshelf on the left and a wooden coffee table holding a mug, wooden tray and a vase of white flowers.

  • Steady, even comfort

    Instead of short bursts of heat, it keeps a gentle, steady output going. The house stays at one comfortable temperature.

    A golden retriever sleeps on a braided gray rug beside a navy upholstered armchair holding an open book, with a lit floor lamp, side table with mug, curtained window showing frost-covered branches at dusk, and a stone fireplace with built-in blue shelves.

  • No gas line, nothing burning in the house

    There's no gas line to the unit and no flame anywhere in it. Carbon monoxide isn't part of the picture.

    A kitchen with a navy blue island topped by a white marble-look counter holding a black induction cooktop, a light blue kettle and a glass vase of hydrangeas, with white cabinets and a stainless wall oven in the background.

Where does a furnace shine?

  • Strong, steady heat in hard cold

    Winter nights here average 19°F, and a furnace puts out hot air from the first cycle no matter how cold it gets outside. It doesn't have to work harder as the temperature drops, it just keeps burning gas and pushing heat.

    A dark-sided two-story house with white trim and a covered front porch, its windows lit at dusk, with deep snow banked along a shoveled walkway to the steps and bare trees at left.

  • Runs on the gas most homes here already use

    86.7% of homes in Kendall County already heat with gas, so the line to your house is probably already there. A gas furnace just uses what's already hooked up.

    Front porch steps with light blue painted railings on a clapboard house, beside a cleared sidewalk bordered by snow, with a dark blue porch on a neighboring house and bare trees in the background.

  • Proven, simple, easy to get serviced

    Parts are easy to find and most repairs are routine. Getting one fixed rarely means waiting on a specialist.

    A gloved hand holds a pleated air filter in front of a furnace and shelving unit in an indoor utility space.

Cold is the real question here

Winters here settle the question before cost does. The overnight low averages 19°F across December, January and February, and that's below both marks that matter for a heat pump. Below 40°F, a standard heat pump puts out less than its rated capacity. Below about 35°F, it typically needs backup heat to keep up. At 19°F average, your house is living in that gap most of the winter, not visiting it on a bad night.

Heat runs eight months a year here, October through May, and about 135 of those nights drop to freezing or below. That's over half the heating season spent below the point where a standard heat pump starts to struggle. Only about 10 nights a year hit 0°F, so the deep cold is rare, but the cold that actually hurts a heat pump's output starts well above zero.

A cold climate heat pump changes this. To earn that label a unit has to hold onto at least 70 percent of its 47°F heating capacity at 5°F, and still produce more heat than electricity put in at that temperature, tested by a third party rather than claimed by the manufacturer. Field tests of these units in occupied homes found backup heat carried only a small share of the load between 0°F and 35°F, and the units ran on backup alone only rarely, even above 0°F. A standard heat pump and a cold climate one are not the same machine in a winter like this one.

A two-story navy blue house with light blue shutters, white trim, a small columned front porch and stone foundation, with a snow-covered lawn, bare trees, and a concrete walkway leading to the sidewalk.

What it costs to run, and what's already in the house

A gas furnace is cheaper to run here. At Illinois's current prices, a furnace makes the same heat for $1.33 per 100,000 Btu against $2.12 for a heat pump built to the federal minimum, which is at least 37 percent less. That gap holds for the full eight months heat runs, since the furnace doesn't lose capacity in the cold the way a standard heat pump does.

Most homes in the county are already set up for it. Utility gas heats 86.7 percent of homes here, electricity 9.7 percent, so a furnace is very likely a straightforward swap for whatever's already heating your house, while a heat pump may mean new electrical capacity if your panel wasn't built with one in mind. That's worth checking against what your house actually has before deciding.

The furnace has nothing to do the other four months of the year, while a heat pump runs your air conditioning too, which the cost comparison above doesn't capture since it only prices heat. If the choice is close on winter running cost, that's the part worth weighing: one machine covers twelve months, the other covers eight and needs a separate air conditioner for the rest.

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

Snow-covered front steps and white railings lead to a dark navy door with a nine-pane window on a light blue clapboard house, with a snow shovel leaning beside the door and snow-laden shrubs on either side.

Common questions about heat pumps and furnaces

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

    Yes, but not at full strength on the coldest nights. A standard heat pump puts out less than its rated capacity once it's below 40°F outside, and the overnight low here averages 19°F across December, January and February. Cold climate models are built to keep more of their capacity down into single digits, but a standard one will need backup heat on the coldest nights to keep up.

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

    Most homes here will want it. A standard heat pump's heating efficiency drops below about 35°F, and nearly all of the about 135 nights a year that reach freezing or below fall under that mark. Field testing on cold climate models found backup heat only supplied a small share of the total heat and rarely carried the whole load even above 0°F, so how much backup heat matters depends on which heat pump goes in.

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

    Yes, and here that often makes sense. The furnace takes over when it's too cold for the heat pump to work efficiently, usually somewhere below 35°F, so it ends up running on the coldest nights of the roughly 135 a year that hit freezing or below. The heat pump handles the rest of the heating season and all the cooling, and the furnace stays in place using the gas line already there.

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

    No, a gas furnace costs less to run here. A furnace makes the same heat for $1.33 per 100,000 Btu against $2.12 for a heat pump, both at Illinois's average fuel prices and each machine built to its federal minimum efficiency. That gap doesn't include the cost of backup heat on the coldest nights, which would widen it further for a standard heat pump.

A man in a light blue polo shirt and dark jeans kneels in a basement, holding a panel on a gray furnace connected to sheet-metal ductwork, with an open tool bag on the floor nearby.

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