Illinois Heating

Heat pump vs furnace in LaSalle County, Illinois

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Serving LaSalle County homes

Which costs less to run in LaSalle County?

An outdoor air conditioning condenser unit with a top-mounted fan grille sits on a concrete pad surrounded by mulch, against dark horizontal siding at night.

Heat pump

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

A beige furnace with a louvered upper panel and metal flue pipe stands on a concrete basement floor beside pipes and ductwork, lit by a bare hanging bulb against a dark blue wall.

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?

  • Steady, even comfort

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

    A dimly lit living room at night with a dark blue armchair holding an open book and knit throw, a lit table lamp, a stone fireplace with a log basket, and a yellow Labrador sleeping on a patterned rug.

  • 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 white sofa and blue throw, navy built-in shelves holding pottery and books, a wooden coffee table with a bowl and green hydrangeas, and a large curtained window overlooking a garden.

  • 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 navy blue whistling kettle sits on a black induction cooktop set into a light stone island with navy cabinets, with wooden open shelves holding bowls and plants, a stainless steel refrigerator, and a window with green trees behind.

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 slow ramp up needed. That steady blast matters most on the coldest nights, when the house is losing heat fast and you want it back quick.

    A two-story house with a lit porch and glowing windows at dusk, with a shoveled path lined by small lanterns leading through deep snow to the front steps, and a large bare tree trunk at right.

  • Runs on the gas most homes here already use

    Most homes in LaSalle County already have gas line run to them, 76.1% heat with it. A furnace just uses what's already there.

    A row of attached houses along a snowy sidewalk, with concrete front steps, navy and white porch railings, brick and painted siding facades, and an exterior gas meter with piping at right.

  • Fast, strong heat on demand

    A furnace pushes out hot air within minutes of switching on. A cold house warms up fast.

    A mudroom with a dark blue door where a person in a dark coat reaches for the handle, snowy boots on a rug, a steaming mug on a wooden bench with wicker baskets, and a coat and throw hanging on wall hooks.

Can a heat pump handle winter here

Your furnace or heat pump has real work to do here. Heat runs about eight months a year, October through May, and the overnight low averages 19°F across December, January and February. That's the question to answer before anything else: can a heat pump keep up on the nights that matter.

A standard heat pump starts falling short before it gets that cold. Below 40°F its heat output drops under its rated capacity. Below about 35°F it often needs backup heat to make up the difference. In LaSalle County, about 135 nights a year hit freezing or below, and every one of them is colder than both of those marks. The average winter night here isn't a rare cold snap that catches the system off guard. It's below where a standard heat pump starts struggling, for most of the heating season.

Ten nights a year drop to 0°F or below. That's a small slice of the 135 freezing nights, but it's where a standard heat pump leans hardest on backup heat, usually electric resistance coils, to keep the house warm. A cold-climate heat pump is built for this. To earn the ENERGY STAR Cold Climate label, it has to deliver at least 1.75 units of heat per unit of electricity at 5°F and hold onto 70 percent of its 47°F capacity at that temperature, checked by independent testing. Field tests back this up: in occupied homes running prototype cold-climate heat pumps over two winters, backup heat covered only a small share of the load between 0°F and 35°F, and the system running on backup alone was rare even above 0°F. A standard heat pump and a cold-climate one are not the same machine here. If a heat pump is on the table for this house, which kind it is matters more than almost anything else.

A two-story navy blue house with white trim, a covered front porch and a light blue front door, with snow on the roof and lawn and a cleared concrete walkway leading to the street.

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

Run the numbers at Illinois's own fuel prices and the furnace wins clearly. A gas furnace built to the federal minimum makes the same heat for $1.33 per 100,000 Btu. A heat pump built to that same federal minimum, with nothing added for backup heat, costs $2.12 for the same heat. That's electricity at $46.51 per million Btu against gas at $10.64 per million Btu, and the gap holds even before backup heat is counted on the coldest nights, which would only widen it for the heat pump.

Gas already runs to most houses in this county. Utility gas heats 76.1 percent of homes here, about three in four. Electricity alone heats 13.6 percent, a little over one in ten. That's not a reason by itself, but it means for most houses here a gas furnace is running on a line and a meter that's probably already in place, where a heat pump run on electric backup would be the less common setup.

Summer changes the comparison some. Cooling runs about three months here, June through August, and a heat pump handles both heating and cooling in one system, where a furnace only heats and sits idle the other four months of the year outside heating season. That's worth something if the air conditioner is also due for replacement. But on the question this section is about, heating this house through a LaSalle County winter, the furnace does it for less money, with no backup heat to plan around, and on the fuel most houses here already have.

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

Snow-covered dark steps with white railings lead to a navy front door on a light blue clapboard house, with a snow shovel leaning beside the door.

Common questions about heat pumps and furnaces

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

    A standard heat pump struggles once it gets cold enough, and this county gets that cold often. Below 40°F a conventional heat pump delivers less than its rated capacity, and below about 35°F it typically needs backup heat. The overnight low here falls to freezing or below on about 135 nights a year, over half the nights in the eight months heat runs, and down to 0°F or below on about 10 of those nights.

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

    Most houses here will need it. Standard heat pumps often need backup heat once it drops below about 35°F outside, and the overnight low here averages 19°F across December, January and February. A cold-climate model holds onto more of its capacity in the teens, but a standard unit will lean on backup through much of the winter here.

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

    Yes, and here it makes sense. Pair the heat pump with your furnace and let the heat pump carry the mild months while the furnace takes over once temperatures drop toward freezing. Your overnight low averages 19°F across December, January and February, well past the point where a standard heat pump's output and efficiency both fall off, so the furnace still has real work to do.

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

    No, a gas furnace costs less to run here. The running-cost figures work out to $2.12 per 100,000 Btu for a heat pump against $1.33 for a gas furnace, both at Illinois's average fuel prices and each machine built to the federal minimum. That gap comes from Illinois's electricity price against its natural gas price, not from how hard either machine has to work.

A person in gloves kneels on gravel beside a gray outdoor air conditioning condenser on a concrete pad, working on its copper line connections, with wrenches and a screwdriver on a blue cloth and a tool bag nearby.

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