Wilmette HVAC Replacement Guide (2026)

Wilmette is one of the North Shore's most established suburbs, and its housing tells two stories at once. Along the lakefront and the older east side near Gillson Park, you find century-old homes on boilers and steam radiators. Head west, and the housing shifts to solid mid-century construction on forced-air furnaces and central air, much of it now on its second or third system. That split is the key to understanding HVAC replacement in Wilmette: the right project depends heavily on which part of town, and which era of home, you own.

Two kinds of Wilmette home

The village's mix means replacement work runs the full range:

• Older east-side and lakefront homes often run hot-water or steam boilers and radiators, many decades old and long since converted from their original fuel. These call for boiler replacement and, frequently, a separate solution for summer cooling since they were never built with ducts.
• Mid-century homes further west typically run forced-air furnaces and central AC. Many added central air decades ago and are now aging out of both systems together, making a matched full-system replacement the common project.

Knowing which category your home falls into tells you what kind of installer experience you need and what the job will involve.

For boiler and radiator homes

If your home heats through radiators, replacement is its own discipline. The big early question is whether to replace like-for-like with a modern standard-efficiency boiler or convert to a high-efficiency condensing boiler. Condensing units are genuinely more efficient, but they only deliver their rated savings when the near-boiler piping, venting, and radiators cooperate. In some Wilmette homes a conversion is straightforward and worthwhile; in others a well-chosen standard replacement is the smarter, more honest buy. A good installer looks at your actual system and tells you which fits rather than defaulting to the priciest option. Our boiler versus forced air in older North Shore homes comparison is a useful read if you are weighing whether to stay with radiators at all.

Cooling these homes usually means ductless mini-splits, since tearing ducts into a finished older home is invasive. Keeping the boiler for winter and adding ductless for summer is a sensible, common combination on the older side of town.

For mid-century forced-air homes

In Wilmette's postwar housing, the classic situation is a furnace and air conditioner reaching the end of their lives at the same time. When both are aging, replacing them together as a matched system is usually the most efficient way to buy comfort: the equipment is matched, the changeout happens in one visit, and you pay for one installation. It is also the strongest candidate for stacked rebates.

The most important step in these homes is right-sizing. Renovations, added insulation, and new windows change a home's heating and cooling load, so a proper load calculation beats copying the old equipment's size. Our full system replacement cost guide covers what the combined project involves.

What it costs

As planning ranges on the North Shore:

• Boiler replacement typically runs $7,000 to $15,000.
• Furnace replacement generally lands $4,500 to $9,000, central AC $4,000 to $8,000.
• A matched furnace-and-AC full system runs $9,000 to $18,000.

Where you land depends on your home's age, size, system type, and the condition of existing ductwork, piping, and venting. These are starting points; the only accurate number comes from a written, in-home estimate.

Rebates worth checking

• Nicor Gas offers roughly $225 for a qualifying 97% AFUE furnace, up to about $500 for a qualifying combi boiler, and up to about $100 for a qualifying smart thermostat.
• ComEd offers a tonnage-tiered rebate in the $1,400 to $2,000 range for qualifying cold-climate heat pumps.

Amounts change and some Wilmette addresses are served by North Shore Gas rather than Nicor, so verify current programs. See our ComEd and Nicor rebates guide for the details.

Timing your replacement

Replace heating in early fall and cooling in early spring whenever you can, before the peak-season rush. An aging system that limps toward a winter or summer failure leaves you replacing under pressure, with no time to compare quotes or capture rebates. Our replace your HVAC before winter article makes the case for getting ahead of it.

Putting it together

Wilmette's split housing stock means the right replacement depends on your home. Older radiator homes call for careful boiler work and often a ductless cooling solution; mid-century homes are best served by a matched full-system replacement, right-sized to the home as it is today. Either way, work with a licensed, insured installer who fits the equipment to your actual house.

Learn more about local work on our Wilmette page, and when you are ready to plan it for your specific home, get a written free estimate or call (847) 752-4418.