Why it matters to you
The decision usually arrives on a hot Houston afternoon with a technician in the driveway, so a simple rule helps you think it through. Angi, a home-services marketplace, puts typical central AC lifespan at about 12 to 17 years, and long, humid cooling seasons are hard on outdoor coils and compressors.
Practical guidance
Run the arithmetic with your own repair quote and system age, then get a written replacement quote with model numbers before deciding. Treat either rule as a prompt to compare options, not a verdict: refrigerant type, repair history, comfort problems and efficiency all belong in the decision.
How does the $5,000 rule work?
Multiply the system's age in years by the repair cost in dollars. A 12-year-old system with a $500 repair quote gives 12 × 500 = 6,000, which is above 5,000 and flags pricing a replacement. A 7-year-old system with a $400 quote gives 2,800, which does not. Those figures illustrate the arithmetic only, not typical repair prices.
What is the 50% rule for HVAC repair?
The 50% rule compares the repair quote with the cost of replacing the system. If the repair would cost more than half of a replacement, the rule suggests replacing instead, especially on an older system. Like the $5,000 rule, it is a rule of thumb that needs a real replacement quote to apply.
How long does a central AC last in Greater Houston?
Angi, a third-party home-services marketplace, puts the typical central AC lifespan at about 12 to 17 years and notes that systems in coastal climates rarely last past 15. Houston's long cooling season, with about 111 days a year at or above 90°F at Bush Intercontinental, adds operating hours. Heat pumps also run through the heating season, so they accumulate hours faster.
When do these rules of thumb get it wrong?
They ignore refrigerant type, repair history, comfort problems and efficiency. A system that still uses R-22, whose production ended in 2020, may justify replacement even with a modest repair quote, while a small capacitor repair on an older but healthy system can still make sense. Use the rules to start the conversation, then weigh the full picture.