Repair or Replace? Making the Right HVAC Call

When your furnace or air conditioner fails, the pressure to decide fast can lead to an expensive mistake in either direction. Use these simple tests to make a clear-eyed call.

The 50% rule

If a repair costs more than 50% of the price of a new system — or if your unit is past its expected lifespan — replacement is usually the smarter long-term move.

A related shortcut is the "5,000 rule": multiply the age of the unit by the repair cost. If the result is over 5,000, lean toward replacing.

Know the typical lifespans

• Furnaces: roughly 15–20 years
• Air conditioners & heat pumps: roughly 10–15 years

If your system is near or past these ranges and needs a major repair, you're often pouring money into a unit that will fail again soon.

Lean toward repair when…

• The unit is well within its expected life
• The fix is minor (a capacitor, ignitor, or thermostat)
• It has been reliable and energy bills are reasonable

Lean toward replace when…

• Repairs are becoming frequent
• Energy bills keep climbing
• Some rooms never get comfortable
• Your system uses an old, expensive refrigerant

The efficiency factor

A modern high-efficiency system can cut energy use substantially compared to a 15-year-old unit. Those monthly savings — plus any available rebates — can offset a chunk of the replacement cost over time.

The bottom line

Run the 50% rule, factor in the age of your system, and always get more than one quote. A second opinion on a "you need a whole new system" diagnosis has saved many homeowners thousands.