At what age should you replace an air conditioner?

In Denver, most air conditioners last 15 to 20 years. If your AC is over 15 years old and requires a major repair (like a compressor or refrigerant leak), replacement is almost always recommended because the unit is nearing the end of its useful life anyway.

Should I replace my 15 year old furnace?

If it is working fine, no. However, if a 15-year-old furnace needs a repair exceeding $400, or if the heat exchanger is showing signs of rust or cracking, replacement is highly recommended. 15 years is right at the point where efficiency drops and parts begin to fail rapidly.

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Free Tool

HVAC Repair vs. Replace Calculator

When your furnace or AC breaks down, the hardest question is knowing when to stop pouring money into it. Use our calculator based on the industry-standard "5,000 Rule" to see what makes the most financial sense.

The 5,000 Rule Calculator

Find out if you should repair or replace

System Age (Years)

Estimated Repair Cost ($)

Current Efficiency

Low (80% AFUE / older AC), Medium (90% AFUE / standard AC), High (96%+ AFUE / high SEER AC)

Enter your system's age and repair cost to see the recommendation.

How the "5,000 Rule" Works

The $5,000 rule is the golden standard in the HVAC industry for making objective repair/replace decisions. It removes the emotion from the equation and looks strictly at the math.

Equipment Age (Years) × Repair Cost ($)

If the result is greater than 5,000: The repair is too expensive relative to the remaining lifespan of the unit. Replace it.
If the result is less than 5,000: The unit has enough life left to justify the cost of the repair. Fix it.

Example Scenario

Imagine you have a 12-year-old AC that needs a $500 repair.
12 × 500 = 6,000.
Since 6,000 is greater than 5,000, the rule suggests replacing the unit. Spending $500 on a system that is likely to fail again in a few years is a poor investment.

Other Factors to Consider

•
Refrigerant TypeIf your AC uses R-22 Freon (phased out in 2020), recharging it is incredibly expensive. Replacement is usually better.
•
Safety FirstIf a furnace has a cracked heat exchanger, it can leak carbon monoxide. Never repair this; always replace the furnace.
•
Moving Soon?If you plan to move in the next 1-2 years, favor repairing. You won't recoup the full cost of a new system when selling.

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Repair vs Replace FAQs

The $5,000 rule is a simple formula used by HVAC professionals to determine if a system is worth repairing. You multiply the age of the equipment (in years) by the estimated cost of the repair. If the result is over 5,000, you should replace the unit. If it is under 5,000, repairing it is usually the better financial decision.