Guide · Rooftop units
Repair or replace a commercial rooftop unit?
A practical guide for Austin building owners and property managers deciding what to do with an aging RTU.
The short answer
- Repair when the unit is under about 10 years old and the problem is a part, not the system.
- Lean toward replacement when the unit is 12 to 15 years old or more and the repair costs more than about half the price of a new unit.
- Replace almost always when the compressor fails on an old unit, the heat exchanger is cracked, the coils are corroded through, or the unit still runs on R-22.
1. How old is the unit?
Packaged rooftop units are often rated for 15 to 20 years, but Central Texas heat is hard on them. Long cooling seasons, roof temperatures well above the air temperature and summer storms mean many Austin RTUs are near the end of their useful life at 12 to 15 years.
The age is on the nameplate. The serial number usually encodes the manufacture date, and we can decode it for you on any brand.
2. What does the repair cost compared with a new unit?
A common rule of thumb: if a unit is past about two-thirds of its expected life and the repair costs more than half of what a replacement would, put the money toward replacement. An old unit that has needed several repairs in the last couple of years is likely to keep needing them.
Repair history matters as much as the single repair in front of you. A maintenance record makes this decision easier.
3. What failed?
Many failures are routine parts: capacitors, contactors, condenser fan motors, blower belts, igniters, sensors and controls. These are worth repairing on almost any unit that is otherwise in good shape.
Some failures change the math. A failed compressor on a unit past 10 years, a cracked heat exchanger on a gas unit (a safety issue because of carbon monoxide), coils that are leaking or corroded through, and repeated refrigerant leaks usually point to replacement.
4. What refrigerant does it use?
Units built before about 2010 often use R-22. New R-22 production ended in 2020, so only recovered and reclaimed refrigerant is available and it is expensive. A refrigerant leak on an R-22 unit is a strong reason to replace it.
Most units from the last 15 years use R-410A. New equipment has moved to lower-GWP refrigerants such as R-454B and R-32 under EPA rules. R-410A is still available to service existing units, but supply is being phased down, so expect it to cost more over time.
5. What will it cost to run?
Current rooftop units are considerably more efficient than units installed 15 years ago, especially at part load, which is where Austin equipment spends much of its time. On a building with several old units, the energy savings can cover a meaningful share of the replacement cost over the life of the new equipment.
Austin Energy offers commercial rebates for qualifying high-efficiency air conditioners and heat pumps, including package units. The application has to be submitted before the installation is finished, so ask about it while you're getting bids. Other utilities in the area have their own programs.
6. Has the building changed?
A new tenant layout, more people, more equipment or a different use can leave the old unit undersized or oversized. A replacement is the right time to check the load instead of just matching the old nameplate.
Repair or replace at a glance
| Factor | Usually repair | Usually replace |
|---|---|---|
| Unit age | Under about 10 years | 12–15 years or more |
| Repair cost | Small next to a new unit | More than about half the cost of a new unit |
| Type of failure | Capacitor, contactor, fan motor, belt, controls | Compressor on an old unit, cracked heat exchanger, corroded coils |
| Refrigerant | R-410A or newer | R-22 |
| Repair history | First problem in years | Several repairs in the last two years |
| Comfort | Building is comfortable when it runs | Can't keep up on hot afternoons |
If you replace: what to plan for
- Curb adaptersA new unit rarely fits the old curb exactly. An adapter curb avoids cutting the roof and usually saves time and money.
- Crane and accessMost RTU replacements need a crane. We schedule the lift, the street or parking-lot closure and the building's notice.
- PermitsMany cities require a mechanical permit for an HVAC replacement. We pull it and schedule the inspection.
- TimingReplacing in spring or fall avoids a summer emergency and lets the change-out happen on a weekend or after hours.
- Lead timesSome units ship in days and others take weeks. Planning ahead lets you choose the equipment instead of taking whatever is in stock.
Every building is different. If you're weighing a repair against a replacement, we'll look at the unit, the repair history and the roof and give you a written price for both options. See our rooftop unit services and maintenance agreements.
Common questions
How long does a commercial rooftop unit last in Austin?
Often 12 to 15 years in Central Texas, sometimes longer with good maintenance. Heat, roof exposure and how many hours the unit runs all shorten its life.
Can I still repair an R-22 rooftop unit?
Yes, many repairs that don't involve the refrigerant are still worth doing. But R-22 is no longer produced, so a leak or compressor failure on an R-22 unit usually makes replacement the better choice.
How long does an RTU replacement take?
Once the equipment is on site, most single-unit change-outs on an existing or adapted curb are done in a day, including the crane lift and startup. Lead time for the equipment is usually the longest part.
Is there a rebate for replacing a commercial unit in Austin?
Austin Energy offers commercial rebates for qualifying high-efficiency air conditioners and heat pumps. Program rules and amounts change, and the application must be in before the installation is finished, so check the current program while you're getting bids.
Have an aging unit on your roof?
Call to talk through the job, or send the details and drawings for a written bid.