Repair or Replace? How to Know When It’s Time for a New Furnace or AC

Start with age

Most furnaces last about 15 to 20 years, depending on how they’re used and maintained. Central air conditioners typically land in the same 15 to 20 year range. Those are averages. Maintenance, climate, and the quality of the original installation can push a system above or below that window.

Weigh the repair cost

Repairs on older equipment add up quickly. A common rule of thumb is that if repairs would cost 25 percent or more of a new furnace, replacing it is worth a serious look. It’s a guideline, not a law. A $200 fix on a 7-year-old unit is usually money well spent. A $1,500 repair on a 19-year-old unit is a tougher call, especially if more breakdowns are likely.

Look at efficiency

An old furnace may be sending a good share of your gas bill up the flue. On the cooling side, ENERGY STAR-qualified central air conditioners are about 15 percent more efficient than standard models.

Signs it may be time to replace

• Your furnace is 15+ years old, or your AC is approaching 15 to 20.
• You’ve needed several repairs in a short period.
• Your energy bills keep climbing and your habits haven’t changed.
• Some rooms never get comfortable.
• You’re hearing new or unusual noises.
• The system runs constantly or turns on and off in short bursts.
• Safety comes first. A cracked heat exchanger, a gas smell, or any carbon monoxide concern is not a “wait and see” situation. Shut the system off and call a professional immediately.

A simple way to think about it

Repairing usually makes sense when:

• The system is relatively young.
• The problem is a single, affordable part.
• It’s been reliable and your bills have stayed steady.

Replacing deserves serious thought when:

• The system is at or past its expected lifespan.
• The repair is a big chunk of what a new unit would cost.
• You’re dealing with repeated repairs or rising energy costs.

Size and installation matter

A new system only delivers on its promises if it’s sized correctly and installed well. Bigger isn’t automatically better. When you get a quote, make sure the contractor sizes the system to your home rather than simply matching your old unit.

Not sure which way to go? We’ll evaluate your system, give you an honest assessment, and walk you through the numbers for repair and replacement so you can decide with confidence. Call AJ’s Appliance Repair and HVAC at 586-789-7876 or fill out our contact form. Serving HVAC customers in Metro Detroit, West and Mid Michigan areas.