Heat Exchanger Repair and Replacement in Chicago

As a rule, no. Welding or sealing a crack is not a sound fix, because the metal has fatigued and a patch can fail out of sight. Trane says it would not recommend repair, and Lennox says repairs are rarely recommended. So heat exchanger repair usually means fixing a fault that only looked like a crack, replacing the exchanger or replacing the furnace. Diagnosis decides which.

City & Suburban does not post a price list for this job, because the furnace sets it. Labor is high since the furnace is largely taken apart, and a covered part leaves mostly labor. A new furnace sits above it in cost, but it also resets the age of every other part. Nisha J. wrote in a Jun 2026 Google review of an AC job, after asking about a new furnace: "he gave us honest advice instead of pushing a massive, expensive project."

A sound inspection looks inside with a mirror and a camera, then runs the furnace. The technician watches the flame as the blower starts and reads combustion gases with an analyzer. High carbon monoxide can have other causes, and a hairline crack may open only when hot. A photo or video is the strongest proof. Burners that will not light at all point elsewhere, to igniter and flame sensor repair.

Not always, and nobody should promise either way. A crack may open only at full heat, and blower pressure changes what escapes. So a confirmed crack means shutting the furnace off, even with a quiet alarm. The Illinois Carbon Monoxide Alarm Detector Act calls for an alarm within 15 feet of every sleeping room. In Chicago, Peoples Gas lists 911 for carbon monoxide and 866-556-6002 for a gas smell. The source can also be a blocked vent, a stove or a water heater.

No. Once a crack is confirmed, the furnace stays off, even in January. Electric space heaters can bridge the gap if kept 3 feet from anything that burns. The usual order is diagnosis, a part lookup by model and serial number, any order wait, then the install. Timing varies. City & Suburban offers same-day service when the schedule allows. Emergency service runs every day till midnight, except Sundays. Roxana B. wrote in an Apr 2025 Google review: "I was freezing and he came out right away."

The tag stays on and the gas stays off at that appliance. Peoples Gas says gas to an appliance or building may not be restored until repairs are made. Not every tag means a crack, since a vent or piping fault can earn one too. North Shore Gas and Nicor Gas serve many suburbs, so their steps may differ. City & Suburban diagnoses the furnace against the condition the utility named. A tagged furnace may need only furnace repair, not a new unit. Austin H. wrote in a Nov 2024 Google review: "our natural gas company let us know that we needed some repairs done, and after a phone call to City & Suburban, they came out the same day so that we could have our gas turned back on."

Yes, when nobody has shown the crack. Where one person both finds the crack and earns more on a new furnace, the setup itself calls for proof. That is a question about incentives, not a claim that the finding is wrong. Trane advises asking to see the cracked part. A homeowner can also ask for photos, readings and the exact location. City & Suburban diagnoses before quoting. The furnace stays off meanwhile.

Heat stress, mostly. Each heating cycle stretches the metal and lets it shrink again, and overheating speeds that up. Packed filters, blocked returns and small ducts starve the furnace of air. Oversized furnaces cycle hard, and moisture adds corrosion. A failing blower motor can do the same damage. A new exchanger on the same airflow fault can meet the same end, so City & Suburban looks for that cause in the diagnosis.

Age and warranty decide most cases. A young furnace with a covered part usually favors the swap, if the part exists. An older furnace keeps its other aging parts after a swap, and a special order can mean days without heat. City of Chicago permit data for the 24 months to August 2026 shows 321 permits mentioning a furnace, with an $18,048 median. Other trades often ride along on those filings, so that figure does not price a furnace alone. For the full job, see furnace installation at City & Suburban, which installs American Standard equipment.

A yearly tune-up should include a look at the exchanger area, but that is not always a full camera inspection. A homeowner can ask what the visit covers before booking. Buying a home is a good reason to ask, since a home inspector's flag often calls for a closer look.

Airflow is the part a homeowner controls. A clean filter, open vents and clear returns keep the furnace inside its temperature range. A damp basement, a leaking humidifier or a blocked drain can rust the metal, so those deserve a fix. A yearly tune-up can catch a rising temperature or an uneven flame early. City & Suburban maintenance plans include seasonal check-ups and priority dispatch.

Often the part, rarely the labor. American Standard's current published terms list 20 years on a furnace heat exchanger under both its base and registered warranties. They say labor is not covered under either. Older models and other makers set their own terms, and owner transfers can change them. The model, serial number and install date settle it.

Chicago does not require a permit for HVAC repair or maintenance. A new furnace is equipment replacement, which needs a City permit. Suburbs set their own rules. Boilers and packaged units hold exchangers too, and those jobs fall under boiler service and rooftop unit service.

In a rental, the owner who supplies the heat or the equipment usually pays. The Chicago Heat Ordinance generally requires 68 degrees by day and 66 overnight from September 15 until June 1. A furnace left off quickly becomes the owner's problem. A tenant should tell the owner first, then call 311. In a condo, the declaration usually decides who owns the furnace. City & Suburban gives the price to whoever approves the work.