Illinois Heating

Heat pump vs furnace in Cook County, Illinois

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Which costs less to run in Cook County?

An outdoor air conditioner condenser unit on a concrete pad beside a dark blue horizontal-siding wall at night, with conduit and a small electrical box on the wall and grass surrounding the pad.

Heat pump

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

A beige sheet-metal furnace stands on a concrete basement floor against a dark blue painted block wall, with galvanized flue ducts rising to the ceiling and a flexible metal conduit and PVC pipe at its left 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?

  • 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.

  • No gas line, nothing burning in the house

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

    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.

  • Heats and cools in one system

    One machine handles the heat in winter and the cooling in summer. There's no second system to buy or keep up.

    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.

Where does a furnace shine?

  • Strong, steady heat in hard cold

    Cook County nights average 20°F through December, January and February. A furnace burns gas for heat, so it puts out the same warm air at 2am in a cold snap as it does on a mild evening.

    A two-story dark blue house with white trim, lit windows, a balcony and a stone chimney at dusk, with a shoveled path through deep snow lined by small lanterns, bare trees at left and a snow-covered evergreen at right.

  • Runs on the gas most homes here already use

    Most homes in Cook County already have the gas line a furnace needs, 80.2% of them heat with utility gas. If your house is one of them, a furnace just uses what's already run to the house.

    A row of closely spaced two-story houses along a sidewalk with patchy snow, the nearest with concrete steps and dark blue wooden railings and a gas meter at the foundation.

  • 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 winter here does to a heat pump

Cook County winters push a standard heat pump into its weak range for most of the season. Its heat output starts falling short of the rating once it's below 40°F outside, and below about 35°F it often needs backup heat to keep up. The average overnight low here, December through February, is 20°F. That's below both marks, every night, all winter.

About 110 nights a year here drop to freezing or below. Every one of those nights is below the 35°F point and the 40°F point. That's not a cold snap, it's under half the nights in the eight months your heat runs. A heat pump sized for this county is working below its rating on most of the nights it's needed most.

The real cold, 0°F or below, only hits about 5 nights a year. That's the part a cold-climate heat pump is built for. Look for the ENERGY STAR Cold Climate mark: it requires the unit to still produce 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 outside testing. A standard heat pump isn't built or rated to do that.

Field testing on cold-climate models backs this up. Across two winters in occupied homes, backup heat only covered a small share of the heat needed between 0°F and 35°F, and the units ran on backup alone only rarely, even above 0°F. So the gap here isn't whether a heat pump can handle a Cook County winter. It's which heat pump, and whether it carries that rating.

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

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

At Illinois's current prices, a gas furnace makes the same heat for less: $1.33 per 100,000 Btu against $2.12 for a heat pump at the federal minimum. That gap doesn't include backup heat, which a standard heat pump will lean on through most of this county's winter nights. A cold-climate model narrows the gap some by needing less backup, but gas stays the cheaper fuel to burn here.

Four in five homes in Cook County already heat with utility gas. Under one in five use electricity. If your house already has a gas line and a furnace, a new furnace uses what's already there. A heat pump means new electrical work alongside it, since a standard one won't carry the house alone through a Cook County winter.

Heating runs eight months a year here, October through May. Cooling runs three, June through August, with afternoons averaging 82°F. A furnace only does the first job. A heat pump does both, which matters if your air conditioner is also due. That's the real trade: a furnace that's cheaper to run and matches what's already in most houses here, against a heat pump that replaces two systems with one and costs more to run doing it.

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

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

Common questions about heat pumps and furnaces

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

    It can, but not at full strength on the coldest nights. A standard heat pump's output falls below its rating once it's under 40°F outside, and Cook County's winter average low of 20°F sits well past that mark. On the roughly 110 nights a year that drop to freezing or below, a heat pump built to the federal minimum is working below its rated capacity the whole time.

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

    Most homes here need it. A standard heat pump starts needing backup heat once it's below about 35°F outside, and Cook County's winter nights average 20°F, with about 110 nights a year at or below freezing. A cold-climate model holds up better in deep cold, but the common setup here pairs a heat pump with a furnace or another backup source for the coldest nights.

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

    Yes, and in Cook County it's a common setup. The furnace handles the cold nights, down near 20°F or lower, and the heat pump covers the milder stretches of the eight-month heating season. You get the furnace's strong heat in hard cold and the heat pump's even comfort the rest of the time, without either one running outside what it's good at.

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

    No, a furnace costs less to run here. Heating with a furnace runs $1.33 per 100,000 Btu against $2.12 for a heat pump, at Illinois's average fuel prices. That gap comes from the price of electricity against natural gas in Illinois, not from either machine being less efficient at what it does.

A gloved worker in dark blue coveralls kneels beside a gray outdoor heat pump unit on a concrete pad, connecting insulated copper refrigerant lines to brass service valves, with pliers and a cordless drill lying on gravel in the foreground.

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