Boiler vs Forced Air in Old North Shore Homes

If you own an older home in Evanston, Winnetka, Wilmette, Kenilworth, or Highland Park, there is a good chance you heat with a boiler and radiators rather than a furnace and ducts. That is not an accident. A lot of the North Shore's housing stock was built before central forced-air was common, and hot-water or steam boilers were the standard way to keep a house warm. When it comes time to replace an aging system, the honest answer is usually not "switch to whatever is trendy." It is "work with what your house was built for, and fix the real gap, which is almost always cooling."

Here is a plain look at how the two systems compare, where each one shines, and what it actually costs to change lanes.

What each system is, in plain terms

A boiler heats water and sends it through pipes to radiators, baseboard units, or in-floor loops. The heat radiates into each room. There is no blower and no ductwork. Steam boilers are an older variant that sends steam up to the radiators instead of hot water.

A forced-air furnace heats air and a blower pushes that warm air through a network of supply and return ducts. The same ducts can carry cool air in summer if you add a central air conditioner, which is a big part of why forced-air homes get central AC so easily.

That single structural difference - water in pipes versus air in ducts - drives almost every decision below.

Comfort: radiant even heat vs forced-air convenience

People who grew up with radiators tend to defend them, and there is a real reason for that.

• Boiler/radiator heat feels even and quiet. The heat is gentle and steady, there are no gusts of air, and there is no blower noise. Rooms hold temperature well. Many older North Shore homes feel genuinely cozy on a January night because of this.
• Forced air heats up fast and adds filtration. A furnace can bring a cold room up to temperature quickly, and because the air is constantly circulating through a filter, it also does a better job with dust and allergens. The tradeoff is that it can feel drafty, and rooms farthest from the furnace can run cooler.

Neither is "better" in the abstract. If even, quiet warmth matters most to you, radiators are hard to beat. If fast recovery and air filtration matter more, forced air has the edge.

The real problem: cooling a radiator home

Here is where boiler homes hit a wall. Radiators heat, but they do nothing for summer. And because there are no ducts, you cannot just bolt on a central air conditioner. This is the single biggest frustration for North Shore owners of older homes, and it is worth being clear about the three realistic ways to add cooling.

For most owners keeping their boiler, ductless mini-splits are the pragmatic answer. They add efficient cooling (and can even provide some shoulder-season heating) without tearing the house apart. Our ductless mini-split guide walks through how zoning works if you want to go deeper, and you can see the scope of that work on the ductless mini-split service page.

The expensive temptation: converting radiators to forced air

Every so often a homeowner asks whether they should just rip out the radiators and convert the whole house to forced air so they can have "normal" central heat and AC. It is a fair question, and the honest answer is usually no.

Converting a true radiator home to forced air means adding a full network of supply and return ducts to a house that was never designed for them. In the older, finished, often plaster-walled homes common on the North Shore, there is rarely a clean path for that ductwork. It typically means soffits, chased-in runs, reduced closet space, opened ceilings, and a lot of patching and repainting. You are paying to demolish a heating system that may work perfectly well, then paying again to build an entirely new one.

In most cases the smarter money is:

1. Replace the boiler with an efficient modern unit so your heat is reliable for another couple of decades. See the boiler replacement service for what that involves, and boiler replacement cost in Illinois for typical ranges.
2. Add ductless cooling for the summers you actually need it.

That pairing gets you the comfort of radiant heat plus real air conditioning, usually for far less disruption and often less money than a full forced-air conversion.

What it costs (typical ranges, always verify)

Every home is different, and prices move, so treat these as starting points and get a written in-home estimate before you budget anything.

• Boiler replacement: typically $7,000 to $15,000 installed, depending on size, fuel, and whether it is hot-water or steam.
• Furnace replacement (if you already have ducts): typically $4,500 to $9,000 installed.
• AC added to an existing forced-air system: typically $5,000 to $10,000 installed.
• Ductless mini-splits: vary widely by number of zones; a written estimate is the only honest number.

Because these ranges overlap and depend heavily on your specific house, the value of an in-home visit is that an installer can look at your venting, your radiators or ducts, and your electrical panel before quoting anything.

An honest recommendation by home type

• Older radiator home you plan to keep long-term: Replace the boiler, add ductless cooling. Do not convert to forced air.
• Home that already has ducts and a furnace: Stay forced-air. Replace the furnace and, if needed, the AC. Consider a full system replacement if both are aging out together.
• Gut renovation with walls already open: This is the rare case where adding ductwork can make sense, because the disruption is already happening. Weigh it against keeping the boiler and adding high-velocity cooling.
• Mixed system that limps along every winter: Get a load calculation and an honest assessment rather than patching year after year.

Towns like Evanston and Winnetka are full of homes where a boiler-plus-ductless setup is the right call, and our Evanston boiler replacement guide covers the local specifics in more detail.

The bottom line: match the solution to how your house was built, and spend your money fixing the real gap rather than replacing a system that already works.

Ready for a straight answer about your specific home? Request a written estimate at /free-estimate or call licensed, insured installers at (847) 752-4418.