Furnace Repair vs Replacement: How to Decide

Every winter, I get the same question from homeowners across Chicago's South Side: should I keep repairing this old furnace or should I replace it? It is a fair question, and the answer is different for every situation. Unlike the big franchise companies that want to sell you a new system every time they walk through your door, I am going to give you an honest framework for making this decision.

I am not a salesman. I am a repairman. That means I will fix your furnace if it can be fixed. But it also means I will tell you the truth when replacement is the smarter investment.

The Age Factor

Most furnaces last between 15 and 25 years, depending on the brand, how well they were maintained, and how hard they have worked. Chicago furnaces work harder than furnaces in mild climates because our winters are brutal. If your furnace is under 10 years old, repair is almost always the right call. If it is between 10 and 15 years old, you need to weigh the cost of the specific repair against the remaining life of the unit. If it is over 20 years old and needing frequent repairs, replacement starts making financial sense.

The Repair Cost Rule

Here is my rule of thumb that I have used for 60 years. If the repair costs more than half the price of a new furnace, replace it. If your furnace is over 15 years old and the repair costs more than a third of a new unit, think seriously about replacement. A new mid efficiency furnace installed in a typical Chicago home runs between $3,000 and $6,000. A high efficiency unit runs between $5,000 and $10,000. Compare your repair quote against those numbers.

Frequency of Repairs

A furnace that needs one repair every few years is normal. A furnace that needs a repair every winter is telling you something. If you have called a technician three or more times in the last two winters, your furnace is on its way out. Each individual repair might seem reasonable, but add them up over two or three years and you could have put that money toward a new system.

Energy Bills Climbing

Old furnaces lose efficiency as they age. A furnace that was 80% efficient when it was new might be running at 65% efficiency after 20 years of wear. That means 35 cents of every dollar you spend on gas is going up the chimney instead of heating your home. New high efficiency furnaces run at 95% to 98% efficiency. In a Chicago winter where your furnace runs six months a year, the savings on your gas bill can be significant. I have seen customers cut their winter gas bills by 30% or more after upgrading.

Safety Concerns

This is the most important factor, and it is non negotiable. If your furnace has a cracked heat exchanger, replace it. A cracked heat exchanger can leak carbon monoxide into your home, and carbon monoxide kills. Do not let anyone tell you a cracked heat exchanger can be "patched" or "monitored." It cannot. If your technician finds cracks in the heat exchanger, that furnace needs to come out. Period.

Other safety red flags include visible rust on the furnace body or flue, a yellow or flickering pilot light (which should be steady blue), soot or scorch marks around the furnace, and the smell of rotten eggs near the unit.

High Efficiency vs Standard Efficiency

If you decide to replace, you will need to choose between a standard efficiency furnace (80% AFUE) and a high efficiency furnace (90% to 98% AFUE). Standard efficiency units cost less upfront and use a simple chimney vent. High efficiency units cost more but vent through PVC pipe through a wall instead of a chimney, and they extract much more heat from the same amount of gas.

In most Chicago homes, I recommend high efficiency. The gas savings pay back the extra cost within 5 to 8 years, and you get another 15 to 25 years of lower bills after that. The one exception is if your budget is very tight and you need heat right now. A good 80% furnace will keep you warm and safe.

What Burris and Sons Recommends

When I come to your home, I inspect your furnace thoroughly. I check the heat exchanger, the burners, the blower motor, the ignition system, the gas valve, the venting, and the controls. I give you an honest assessment. If your furnace can be safely repaired for a reasonable cost, I will repair it. If replacement makes more sense, I will explain why and give you options.

I carry all the major brands and install all makes and models. I do not push one brand over another because I have a deal with them. I recommend what is right for your home, your budget, and your situation.

Getting Ready for Next Winter

If your furnace struggled this past winter, do not wait until November to address it. Schedule an inspection now while service is less backed up and prices have not hit peak season. A furnace tune up and inspection costs a fraction of an emergency repair, and it will tell you exactly where your system stands.

Call Burris and Sons at 773-375-4123 for an honest assessment of your furnace. We serve South Shore, Hyde Park, Englewood, Chatham, Woodlawn, Auburn Gresham, Roseland, Pullman, and all surrounding neighborhoods.