Most London homeowners wait too long to replace an aging furnace, paying for expensive repairs on a system that is near the end of its useful life. Here are the seven signs that replacement makes more financial sense than another repair.
A gas furnace in London, Ontario has an average useful life of 15 to 20 years with proper maintenance. After that point, the cost-benefit calculation shifts decisively toward replacement. But age alone is not the only factor. Here are the seven signs we look for when advising London homeowners on whether to repair or replace.
A furnace that has needed multiple repairs in recent years is telling you something. Components fail in clusters as a system ages. Replacing one part often reveals that the next part is also near the end of its life. If your furnace is over 15 years old and you have spent more than $500 on repairs in the past two years, the money is better directed toward a new, more efficient system.
An aging furnace loses efficiency as heat exchangers corrode, burners foul, and blower motors wear. A furnace that was rated at 80% AFUE when new may be operating at 65 to 70% efficiency after 15 years of service. A new high-efficiency furnace rated at 96% AFUE can reduce your heating costs by 20 to 30 percent annually. In London's climate, that is a meaningful saving over a heating season.
A cracked heat exchanger is a carbon monoxide hazard and, in most cases, a reason to replace the furnace rather than attempt a repair. Heat exchanger replacement is expensive, often costing more than half the price of a new furnace, and does not address the underlying wear on the rest of the system. If a technician has identified a cracked heat exchanger, get a replacement quote before authorising the repair.
Short-cycling, where the furnace turns on and off repeatedly without completing a full heating cycle, can indicate an oversized unit, a failing heat exchanger, or a control board problem. A furnace that runs continuously without reaching the set temperature may be undersized, have a refrigerant issue in a heat pump system, or be losing efficiency due to age. Both patterns waste energy and put extra wear on the system.
If some rooms in your London home are consistently colder than others and the ductwork has been checked, the furnace may no longer be producing adequate heat output. This is particularly common in older single-stage furnaces that cannot modulate their output to match varying demand.
Banging, rattling, squealing, or rumbling sounds from a furnace are not normal. Banging on startup often indicates delayed ignition, which is a safety concern. Rattling can indicate loose components. Squealing points to blower motor bearing failure. While some of these issues are repairable, they are also signs of a system that is aging out.
A healthy furnace flame is blue with a small yellow tip. A predominantly yellow or orange flame indicates incomplete combustion, which produces carbon monoxide. This can sometimes be corrected by cleaning the burners, but in an older furnace it often signals deeper problems with the combustion system. Do not ignore a yellow flame.
Use the 5,000 rule as a quick guide: multiply the age of the furnace in years by the estimated repair cost in dollars. If the result exceeds 5,000, replacement is almost always the better financial decision.
Corner Gas HVAC serves London, Ontario and Middlesex County. Same-day service available.
