Furnace Replacement Cost in Illinois (2026)
A gas furnace replacement in Illinois runs $3,500 to $11,000 installed, and most quotes in the Chicago area land between $5,500 and $9,000. Downstate and smaller markets sit lower; high efficiency condensing furnaces in older Chicago homes sit at the top.
At a glance
| Job priced | Gas furnace replacement |
| Full observed range | $3,500–11,000 |
| Where most quotes land | $5,500–9,000 |
| Independent sources triangulated | 3 |
Figures are triangulated from independent published sources for this state, restated to one scope: installed, before rebates, existing ductwork and venting assumed serviceable. The method and its limits are on our method page.
Why Illinois is priced on furnaces
Like Minnesota, Illinois is a heating market first. The job most households are actually quoting is a furnace, so that is what we price here. If you are replacing the air conditioner at the same time, expect the combined job to cost more in total but less per machine. Our heating guide covers furnaces nationally and our air conditioning guide covers the cooling side.
Chicago costs more, and why
Published 2026 Chicago-area data puts a furnace replacement at roughly $5,900 to $10,900, with an average near $8,400, and Chicagoland contractors describe local pricing as about 8 to 12 percent above the national figure. Two reasons stand out: labor rates in the metro, and permitting through the Chicago Department of Buildings, which is stricter than in many suburbs. Suburban quotes in the $5,500 to $11,000 band are common for a complete replacement.
80 or 95 percent AFUE
Most of the price difference between a basic and a premium furnace quote is efficiency. A 95 percent AFUE condensing furnace costs more to buy and often needs new PVC venting and a condensate drain, which an 80 percent furnace venting into an existing chimney does not. In a cold climate the higher efficiency usually pays back over the life of the furnace, but the venting work is real and belongs in the quote. If one quote is far cheaper, check which efficiency it assumes.
Old homes, tight spaces
Chicago bungalows, two-flats and older suburbs often have furnaces in tight basements or closets, chimneys that need a liner, and ductwork sized for a different era. None of that is unusual, but each adds hours. Ask whether the quote includes a chimney liner or venting change if you are staying at 80 percent, and whether anyone measured the ducts.
Check a quote
Before you accept the quote
Get the furnace model, BTU input and AFUE rating in writing, and ask how the size was chosen. An oversized furnace short cycles, just as an oversized air conditioner does. If the quote looks high, our guide to what to do when a quote looks high lists the questions that sort a fair price from padding.
Price sources: Four Seasons Heating and Cooling Chicago furnace replacement cost study 2026, HomeGnome furnace cost data for Chicago, and TemperaturePro Chicago-suburbs replacement guidance, 2026. Planning ranges, not quotes. Last reviewed October 2026.