Repair or replace a 15 year old rooftop unit?
By Tyler Wayne, FMP · Working B2B HVAC Rep on the Wasatch Front · Updated October 2026
Age alone shouldn't make the call. Look at repair history, refrigerant type, parts availability and what the unit serves. A 15 year old unit with a clean record over a lobby can usually wait. The same unit over a server room, with three compressor calls this year, probably can't.
How long commercial rooftop units last
Many commercial rooftop units run 15 to 20 years with good maintenance. Some go longer. Coastal air, heavy run hours and skipped maintenance shorten that. Our dry climate is kinder to cabinets than the coast, but big temperature swings are hard on compressors and heat exchangers.
Signs it's time to replace
- Repeated compressor failures or refrigerant leaks.
- It still runs on R-22. Production ended in 2020, so service depends on reclaimed refrigerant and keeps getting harder.
- A cracked or badly corroded heat exchanger.
- Rusted out cabinets, base rails or curbs.
- Parts that are discontinued or take weeks to find.
- Comfort complaints that keep coming back after repairs.
Signs a repair still makes sense
- One failed part on an otherwise solid unit.
- A good maintenance history and a clean coil and cabinet.
- It serves a space where a short outage is an annoyance, not a crisis.
The question to ask before budget season
What does it cost you when this unit goes down in July? A lobby is uncomfortable for a few days. A server room, a lab or a clinic is a different conversation. Rank your units by that, not just by age.
What to plan for when you do replace
- Lead times. New units can take weeks or months to arrive, so replacing before a failure is calmer than replacing after one.
- The curb. A new unit may not match the old curb, so an adapter or new curb may be needed.
- The refrigerant change. New units use refrigerants like R-454B and R-32. See what the refrigerant change means.
- The crane day. Plan for tenant notice, roof access and weather.
Common questions
How long does a commercial rooftop unit last?
Often 15 to 20 years with regular maintenance. Run hours, maintenance history and climate all move that number.
Is R-22 still available?
New R-22 hasn't been produced in the United States since 2020. Service relies on reclaimed and existing supply, which makes R-22 units harder to keep running over time.
Can a new unit go on the old curb?
Sometimes. Many replacements use a curb adapter. Your contractor should check dimensions before ordering.