Boiler Replacement Cost in Illinois (2026 Guide)

If you heat your home with radiators or baseboard, you own a boiler, and replacing one is a different project than swapping a forced-air furnace. Boiler replacement in Illinois typically runs between $7,000 and $15,000 installed, and where you land inside that range depends heavily on whether you have a hot-water or steam system, whether your home can support a high-efficiency condensing unit, and the condition of the piping around the boiler itself. This guide explains what drives the number, why so many North Shore homes are boiler homes in the first place, and how to read a fair quote. The only way to get a real figure for your house is a written, in-home estimate, but understanding the moving parts helps you ask the right questions.

What a new boiler costs in 2026

Boilers cost more than furnaces because the equipment is heavier, the piping is more involved, and the labor takes longer. Treat every number below as a typical range that shifts with your equipment, home configuration, and the market.

These are installed prices covering equipment, labor, and the piping work at the boiler. Because boiler jobs vary so much house to house, the itemized quote matters even more than it does with a furnace.

Hot-water vs steam boilers

The single biggest fork in the road is what kind of boiler you already have.

Hot-water (hydronic) boilers heat water and circulate it through radiators or baseboard with a pump. Most newer boiler installations are hot-water systems, and they are generally more efficient and more flexible than steam.

Steam boilers boil water into steam, which rises through the pipes to the radiators on its own. Many older North Shore homes still run on steam, and those radiators are often original to the house. Steam boilers are heavier, the installation is more exacting, and the unit itself tends to cost more. You generally replace a steam boiler with another steam boiler unless you are undertaking a much larger conversion, which is a bigger project with its own cost.

Knowing which system you have is the first step, and a licensed installer will confirm it during the visit.

Standard vs high-efficiency condensing

Just like furnaces, boilers come in standard-efficiency and high-efficiency condensing versions. A condensing boiler extracts more heat from the fuel and vents through PVC rather than a chimney, which can lower your gas use meaningfully over a long heating season.

The catch is that a condensing boiler only performs the way it should when the system around it supports lower water temperatures and the near-boiler piping is set up correctly. In some older homes with large cast-iron radiators, a condensing boiler works beautifully because those radiators put out plenty of heat at lower water temps. In others, the existing piping needs rework to get the efficiency you paid for. A good installer will tell you honestly whether your home is a strong candidate for condensing or whether a well-installed standard boiler is the smarter buy. That judgment is worth more than any brochure number.

Why North Shore homes are boiler-heavy

Drive through Evanston, Winnetka, or Wilmette and you are looking at a lot of housing stock built before forced-air was the default. Homes from that era were designed around radiators and boilers, and many still run on them today. That older stock is exactly why boiler work is so common across the North Shore, and it is also why boiler replacements here so often involve carefully matching a new unit to decades-old piping and radiators. If you are weighing whether to stay with a boiler or move to forced air during a major project, we lay out the tradeoffs in boiler vs forced air in old North Shore homes. Evanston homeowners in particular can find a system-specific walkthrough in the Evanston boiler replacement guide.

What a fair boiler quote should include

A complete boiler replacement quote should spell out:

• The boiler make, model, output (in BTU or MBH), and efficiency rating
• Whether it is a hot-water, steam, or combi unit, and confirmation it matches your system
• Near-boiler piping work and any circulator pump replacement
• Proper venting, and a condensate drain for condensing units
• Removal and haul-away of the old boiler
• Startup, testing, balancing, and a walkthrough

Boiler quotes swing more than furnace quotes because the piping work is where the real labor lives. Two bids that look far apart may simply reflect different amounts of piping and pump work, so ask each installer to explain what is driving their number.

Rebates in 2026

For 2026, utility rebates are the main incentive, since the federal 25C tax credit expired for equipment placed in service after December 31, 2025. Nicor Gas offers up to roughly $500 for a qualifying combination boiler, along with rebates on qualifying high-efficiency equipment and smart thermostats, with roughly 90 days to file. Some North Shore towns are served by North Shore Gas instead of Nicor, so check your gas bill to see which utility you have and look up that program's current offers. Rebate amounts change, so verify the current numbers before you count on them. The ComEd and Nicor HVAC rebates guide keeps a fuller breakdown.

How long a boiler installation takes

Homeowners are often surprised that a boiler replacement takes longer than a furnace swap. A straightforward furnace can sometimes be done in a day; a boiler frequently runs a day or two because of the piping work, the water in the system, and the need to purge air out of the lines afterward. Steam boilers can take longer still. This is worth planning for, especially in the depth of winter when you will be without heat during the changeover. A good installer will schedule the work to minimize the gap and, when the weather is severe, may stage the job so your home is not cold overnight. If your boiler has failed completely and you cannot wait, emergency HVAC replacement exists for exactly that situation.

Signs your boiler is nearing the end

You do not have to wait for a total failure to start planning. A few signs point toward a boiler that is winding down:

• Age. Boilers are long-lived, but efficiency and reliability drop as they get well past their intended service life.
• Rising gas bills. If your usage has climbed without a change in habits, the boiler may be losing efficiency.
• Uneven or slow heat. Radiators that take forever to warm up, or rooms that never quite get there, can signal a struggling boiler or a circulation problem.
• Visible corrosion or leaks. Rust around the base or water pooling underneath is a serious warning sign.
• Frequent repairs. When you are calling for HVAC repair every season, the repair spending is often better redirected toward a replacement.

Catching these early lets you plan a replacement on your schedule rather than scrambling during a January cold snap.

Should you replace or keep repairing?

Boilers are durable, and a well-maintained one can last a long time. But once a boiler is leaking at the block, losing efficiency, or needs a major part, the repair money often makes more sense pointed at a new unit. If the boiler is old enough that finding parts is getting hard, that is another sign. A licensed installer can assess whether yours has good years left or whether replacement is the honest recommendation. The right answer is not always replacement; sometimes a well-chosen repair buys you several more good seasons, and an honest installer will tell you when that is the case.

Older homes across the North Shore keep their boilers running for decades, and the range in this guide holds up well across Cook and Lake counties. Your house and your piping are their own situation, though. For a real number, book a written boiler replacement estimate or get our free estimate, and a licensed installer will come look at your actual system. You can also call (847) 752-4418.