Every facility manager eventually gets the call: an RTU is down, the repair quote is in hand, and now there's a decision to make with a budget cycle, a tenant, or an operations team waiting on the answer. Here's a framework that goes past the simple "50% rule" most people default to.
Start with the 50% rule, but don't stop there
The common guideline is: if a repair costs more than 50% of a new unit's installed cost, replace instead of repair. It's a reasonable first filter, but on its own it misses a few things that actually matter more.
Age relative to expected service life
Commercial RTUs are generally expected to run 15–20 years with proper maintenance, less in coastal or high-run-hour environments. A repair on a 6-year-old unit is a very different decision than the same dollar repair on an 18-year-old unit — the younger unit still has most of its life ahead of it, while the older one is a candidate for the next major failure regardless of what gets fixed this time.
Refrigerant type
Units on legacy or phased-out refrigerants come with a real cost and availability risk on any future repair, independent of the unit's age. If a repair on an older-refrigerant unit involves the refrigerant circuit at all, that's a strong signal toward replacement — the next repair may cost significantly more or become harder to source parts for.
What's actually failing
Not all repairs are equal. A failed contactor, capacitor, or blower motor is a normal, low-risk repair on a unit of any age. A failed compressor or a major refrigerant leak in the coil is a different conversation — it's a significant repair cost on a system where other major components are aging at the same rate, and it's often the first of several similar failures rather than an isolated event.
Downtime cost and redundancy
A single RTU serving a server room or a walk-in-adjacent kitchen area has effectively zero tolerance for extended downtime, which changes the math — a faster repair may be worth a premium even if replacement is the better long-term call, simply to buy time to plan and budget the replacement properly instead of doing it under emergency conditions.
A simple framework
- Repair: unit under ~10 years old, current refrigerant type, and the failure is a component-level issue (electrical, motor, minor part).
- Repair now, budget for replacement soon: unit 10–15 years old, or a moderate repair cost that doesn't clear the 50% threshold but the unit is showing other signs of decline.
- Replace: unit over 15 years old, legacy refrigerant involved in the repair, or the repair cost clears 50% of replacement cost on a unit that's already past its expected midlife.
We give straight repair-vs-replace guidance based on the actual unit and readings, not a default push toward replacement. See our RTU install and service page, or ask about a diagnostic visit to get a real recommendation.