Furnace Installation in Chicago, IL
A new furnace here will run from October through May every year. Tell us about the house, and a licensed contractor who covers Cook County will get in touch.
Tell us about the job
It takes about a minute.
Eight months of heat, and nights near 20 degrees
Cook County homes need the furnace running from October through May. That's eight months of the year, and on winter nights the average low sits around 20°F. A furnace built for this has to hold up to a long season, not just a few cold snaps.
Most homes here heat with gas, and any new non-weatherized gas furnace has to reach at least 80.0 percent AFUE. Power matters too. Illinois saw 16% of households lose power for 24 hours or more in 2024, and the last ten years brought 20 winter storms and 548 damaging wind events through the area. A furnace installed here needs to be sized and set up for the cold it will actually face.
- 8 months
- October through May, your furnace is on duty
- 20°F
- the average winter night it heats against
- 80%
- of homes here heat with gas, so most furnaces here burn gas
- 80% AFUE
- the federal minimum any new unit must meet
NOAA nClimDiv, 1991–2020 normals
A high-efficiency gas furnace would save about $130 a year to run in Cook County compared with a gas furnace.
Estimates for a typical Cook County home, from EIA household energy data, Illinois fuel prices and NOAA climate normals. Your home will differ.
In Illinois, HVAC licensing for homes is left to the cities and towns.
In Cook County, whether a contractor needs a license depends on the municipality. Some towns require one, some require the business to register, and some leave it open. There is no statewide test or record behind any of it, so what protects you here comes down to where in the county the house sits.
For a furnace installation, most cities and counties require a permit from the local building office, along with an inspection once the work is done. That is where this job gets checked, not through a state license. In Cook County, 80.2% of homes heat with gas, so a furnace installation is common work here.
Source: Illinois General Assembly
- What size furnace does my house need?
- It depends on your square footage, your insulation, your ceiling height, and how many windows you have, so there's no single number that fits every house. A contractor sizes a furnace by running a load calculation on your home specifically, not by square footage alone. Going too big wastes fuel and wears out the furnace faster from short cycling. Going too small leaves you cold on the nights that hit 20°F, which is a normal low here. Ask whoever quotes the job to walk you through the load calculation, not just a number they pulled from a chart.
- How do I know it's time to replace my furnace?
- Age is one clue, and a contractor can tell you where yours stands against a typical lifespan. Watch for rising repair frequency, uneven heat between rooms, or a furnace that runs longer to hold the same temperature. Homes here need heat from October through May, eight months of the year, so a furnace that's struggling gets tested hard and often. If a contractor tells you the heat exchanger is cracked, that's a straight replace, not a repair.
- Is a high-efficiency furnace worth it?
- It depends on how long you plan to stay in the house and what your furnace is doing now. Furnaces made since November 2015 are already required to hit at least 80 percent AFUE, so the real choice is between that baseline and a high-efficiency model rated well above it. With eight months of heating a year here, and winter nights averaging 20°F, a furnace that runs efficiently is working most of the year, not just a few cold snaps. A contractor can tell you what efficiency level makes sense for your house, since duct layout and insulation affect how much of that efficiency you actually get.