Illinois Heating

Heat pump vs furnace in Stephenson County, Illinois

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For homes in Stephenson County

Which costs less to run in Stephenson County?

A gray outdoor condenser unit with a top-mounted fan grille sits on a concrete pad against dark horizontal lap siding, photographed at night with surrounding bare soil and leaf litter.

Heat pump

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

A beige gas furnace standing on a concrete basement floor against a dark blue wall, with galvanized metal flue ductwork above it and gas piping and a flexible conduit at its right side.

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 dark knit throw, a wooden coffee table with a bowl, books and a mug, a jute rug, wooden sideboard with a lamp and plants, and a large window with linen curtains showing green garden foliage.

  • No gas line, nothing burning in the house

    It moves heat instead of making it from fire. That means no combustion, no flue and no gas bill for heat.

    A kitchen with navy blue shaker cabinets, white subway tile backsplash, light stone countertops, a stainless range hood over a cooktop with a pale blue kettle, and an island holding a vase of white hydrangeas and a bowl of green apples with wooden stools.

  • Steady, even comfort

    It eases up and down with the weather. There are fewer swings between too warm and too cool.

    A golden retriever sleeps on a cream shag rug in a dim living room with a lit wood stove, an armchair with a blue throw and open book, a lamp and mug on a side table, built-in bookshelves, and a window showing snowy evergreens.

Where does a furnace shine?

  • Strong, steady heat in hard cold

    Winter nights here average 15°F, and that's the kind of cold where a furnace just keeps putting out hot air no matter how low it gets outside. You won't notice it working harder, because it doesn't have to.

    A two-story dark blue clapboard house with a white covered porch and lit windows at dusk, surrounded by deep snow, bare trees and small lit evergreens.

  • Runs on the gas most homes here already use

    Most homes in Stephenson County already have gas line run to them, 67.3% heat with utility gas. A furnace just uses what's already there instead of asking for a new setup.

    A row of wood-sided houses with covered porches, concrete steps and metal railings along a snow-covered sidewalk in winter sunlight.

  • 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 white pleated air filter in front of a utility room with wire shelving, storage bins, towels, a blue door, and metal ductwork beside a furnace.

What the cold here does to a heat pump

Winter decides this choice more than anything else in Stephenson County. The overnight low averages 15°F across December, January and February. About 145 nights a year drop to freezing or below, and 16 of those reach 0°F or colder.

A standard heat pump starts falling behind well before it gets that cold. Below 40°F it puts out less heat than its rating says. Below about 35°F it often needs backup heat to keep the house warm. Here, the average winter low of 15°F is below both marks, and every one of those 145 freezing nights is too. That's not a machine straining on a few of the worst nights of the year. It's working under its rating most of the winter.

A furnace doesn't have that problem. It's built to put out the same heat whether it's 30°F outside or 0°F.

Cold climate heat pumps are built for this kind of winter specifically. To carry the ENERGY STAR Cold Climate mark, a heat pump has to make at least 1.75 units of heat per unit of electricity at 5°F and hold on to at least 70 percent of its 47°F heating capacity at that temperature, checked by outside testing. In a two-winter field test of prototype cold-climate units in occupied homes, backup heat covered only a small share of the load between 0°F and 35°F, and running on backup alone was rare even above 0°F. That's a different machine than the standard one the running costs above are based on, and it's worth asking for by name if a heat pump is still under consideration here.

A row of two-story houses with brick lower walls, white porches and blue or light blue siding, behind deep snowbanks along a cleared sidewalk under a clear sky with bare trees.

What it costs to run, and what the house is already set up for

Run the two side by side on cost and the furnace wins. A gas furnace makes the same heat here for $1.33 per 100,000 Btu against $2.12 for a heat pump, using Illinois's actual gas and electricity prices. The heat pump's number is its federal minimum rating alone, with nothing added for the backup heat it would lean on through a Stephenson County winter, so the real gap on a cold night runs wider than that number shows.

Heat is also the long season here, about eight months a year, October through May, against three months of cooling, June through August. A furnace only does one of those jobs. A heat pump does both, and that matters most in a house that would otherwise need a separate air conditioner anyway, since summer afternoons here average 82°F.

Two in three homes in Stephenson County already heat with utility gas, and about one in ten more run on propane. A little under one in five heat with electricity now. If your house already has a gas line to it, running a furnace through it is the simpler path, and the cheaper one, through a winter like this. If it doesn't, or if it's already set up for electric heat, that changes which machine is the easier one to put in.

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

A row of two-story houses with brick and blue siding facades, covered porches and icicles along the eaves, beside a plowed street with snowbanks under a clear blue sky.

Common questions about heat pumps and furnaces

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

    Yes, but a standard heat pump won't carry the full load on the coldest nights here. Below 40°F its heat output falls short of its rating, and below about 35°F it often needs backup heat. The overnight low here averages 15°F across December, January and February, and falls to 0°F or below about 16 nights a year, so it needs backup heat for a real share of the winter.

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

    Most homeowners here will want it. The average overnight low across December, January and February is 15°F, well below the roughly 35°F mark where a standard heat pump's efficiency drops and it often needs help. Of the about 145 nights a year that fall to freezing or below here, every one of them is cold enough to put a standard heat pump below both that mark and the 40°F mark where its output falls short of its rating.

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

    Yes, and here that often means the furnace keeps working when the heat pump struggles. Below about 35°F a standard heat pump often needs backup heat, and the overnight low here averages 15°F across December, January and February. Pairing it with your existing furnace gives you that backup without relying on electric strip heat.

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

    No, a gas furnace is cheaper to run here. At Illinois's average fuel prices, a furnace built to federal minimum efficiency makes the same heat for $1.33 per 100,000 Btu, against $2.12 for a heat pump built to its federal minimum. That heat pump figure also doesn't include the cost of backup heat on the colder nights here, so the gap in practice runs at least that wide.

A person in a navy hooded sweatshirt, tan work pants and a knit cap kneels beside a furnace in a basement utility area, with sheet metal ductwork, PVC and copper piping overhead and a black tool bag on the concrete floor nearby.

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