Commercial Rooftop Unit: Repair or Replace? A Decision Guide

Most commercial rooftop units don't fail all at once. They get louder, the compressor short-cycles, a heat exchanger gets flagged at inspection, and the repair invoices start arriving every few months. At some point someone asks whether it's time to stop fixing it.

There's no single age or dollar figure that answers that. But there is a fairly reliable way to think it through. This guide is for property managers, facility managers and owners of offices, retail plazas, restaurants, warehouses and light industrial buildings with packaged rooftop equipment.

Start with the unit's age and expected life

Packaged rooftop units in commercial service commonly last somewhere in the range of 15 to 20 years, depending on climate, maintenance and how hard they run. Units on restaurants and buildings with long operating hours tend to land at the lower end. Units in coastal salt air can corrode faster.

Age alone doesn't mean replace. A 17-year-old unit with a solid maintenance record and a clean heat exchanger can keep going. But age sets the context for every repair decision. Putting a new compressor in a unit that's near the end of its life is rarely good money.

The repair history test

Pull the last three years of service invoices for the unit. Look for:

• Repeat failures of the same component
• Major components already replaced (compressor, condenser fan motor, inducer motor, control board)
• Refrigerant top-ups, which mean there's a leak somewhere
• Emergency calls in peak weather

A common rule of thumb in the trade: if a single repair costs more than about half of what a replacement would, or if the unit is past roughly two-thirds of its expected life and needs a major component, replacement deserves a serious look. Treat that as a starting point for the conversation, not a hard rule.

Refrigerant matters more than it used to

This is the factor that's changed most in recent years.

In the US, the AIM Act gave the EPA authority to phase down HFC refrigerants, and new rules restrict high-GWP refrigerants like R-410A in newly manufactured equipment in many categories. Manufacturers have moved new rooftop units to lower-GWP refrigerants such as R-454B and R-32. Canada has its own HFC phase-down under the federal Ozone-depleting Substances and Halocarbon Alternatives Regulations, and the market there is following the same direction.

What that means for you:

• Existing R-410A units can still be serviced. But as production of R-410A is stepped down, the refrigerant may get more expensive over time.
• A unit with a chronic leak becomes more expensive to keep running.
• Older units running R-22 are a different story. R-22 production ended years ago, and recharging relies on reclaimed stock. If you still have R-22 equipment and it needs a major repair, replacement is usually the practical answer.

Ask your contractor what refrigerant each unit uses before deciding anything.

Efficiency and operating cost

A new unit will almost always be more efficient than a 15-year-old one. How much that's worth depends on your hours and energy prices.

Look at:

• Cooling efficiency (IEER on commercial packaged units) and heating efficiency
• Economizers. Many older units have economizers that are stuck, disconnected or never worked. A working economizer brings in outside air for free cooling in shoulder seasons.
• Variable-speed fans and multi-stage compressors, which run more efficiently at part load, and part load is where units spend most of their time
• Heat pump options. In a lot of North American climates, rooftop heat pumps with gas or electric backup are now a realistic option and can be eligible for utility incentives. Check your local utility before you sign.

Hidden costs on the roof

Replacement quotes that look similar can differ a lot once the roof work is counted:

• Curb adapters. If the new unit's footprint doesn't match the existing curb, you need an adapter curb. Some manufacturers make direct-replacement units that fit common legacy curbs.
• Crane lifts. Most RTU swaps need a crane. Downtown sites may need street occupancy permits and weekend lifts.
• Structural review. A heavier unit, or a different unit position, may need an engineer to confirm the roof can carry it.
• Electrical and gas. A new unit may need different breaker sizing, a new disconnect or gas piping changes.
• Roofing. Flashing around the curb often needs a roofer, especially on older membranes.
• Controls. If the building has a BMS, the new unit has to talk to it.

Ask each bidder to list these items separately. "Supply and install" without detail hides a lot.

Permits and codes

RTU replacements usually need a mechanical permit from the local building department. Gas work in Canada falls under provincial gas codes (for example, CSA B149.1 is adopted across most provinces), and electrical work under the provincial electrical code. In the US, the mechanical permit and inspection follow the code your city or county has adopted, usually a version of the International Mechanical Code or a local variant. Your contractor should pull the permits and arrange inspections.

Timing: plan around the seasons

The worst time to replace a rooftop unit is when it fails on the coldest or hottest day of the year. Equipment may not be in stock, crane schedules fill up, and you pay emergency rates for temporary heat or cooling.

Better approach:

• Assess units in the fall for heating risk and in spring for cooling risk.
• Order equipment ahead. Lead times vary, and specific tonnages or configurations can take weeks.
• Schedule swaps in the shoulder seasons when the building can tolerate a day without the unit.
• Replace in batches if you have several aging units. One crane day for three units is cheaper than three separate lifts.

For buildings in places like Montréal, Toronto or the US Midwest, October is a good month to flag units with cracked heat exchangers or failing inducers before they're running around the clock.

A simple decision checklist

Replace if most of these are true:

• Unit is in the last third of its expected life
• A major component has failed or is failing
• It runs R-22, or it has a refrigerant leak that keeps coming back
• Repair invoices have climbed year over year
• The heat exchanger has been flagged
• Comfort complaints are frequent despite repairs

Repair if:

• The unit is mid-life with a good record
• The failure is a minor, isolated component
• The building's future is uncertain (sale, redevelopment, lease end) and you need a few more years only

Restaurant buildings: think about make-up air too

If the RTU serves a commercial kitchen, replacement is a good moment to check the make-up air balance with the kitchen exhaust. An exhaust system pulling more air than the building can replace causes doors that won't close, drafts and pilot light problems. We cover the exhaust side in our NFPA 96 kitchen exhaust guide.

Frequently asked questions

How long does a commercial rooftop unit last?

Packaged rooftop units in commercial service commonly last somewhere around 15 to 20 years. Units on restaurants or buildings with long operating hours tend to wear out sooner, and units in coastal salt air can corrode faster. Good maintenance pushes a unit toward the longer end of that range.

When is it worth replacing an RTU instead of repairing it?

A common rule of thumb is to look seriously at replacement when one repair would cost more than about half the price of a new unit, or when a unit past roughly two-thirds of its expected life needs a major component. Repeat failures, recurring refrigerant leaks and a flagged heat exchanger also push toward replacement. Treat these as a starting point rather than a hard rule.

Can I still repair a rooftop unit that uses R-22?

It can be done, but R-22 production ended years ago and recharging relies on reclaimed stock. If an R-22 unit needs a major repair, replacing it is usually the practical choice. R-410A units can still be serviced, though that refrigerant may get more expensive as production is stepped down.

What is the best time of year to replace a rooftop unit?

The shoulder seasons, spring and fall, when the building can manage a day without the unit. Waiting for a failure on the hottest or coldest day often means equipment that is out of stock, booked-up crane schedules and emergency rates. Assessing units in the fall for heating and in spring for cooling gives you time to order equipment.

Get a written assessment

Vulcair assesses and replaces commercial rooftop units across Canada and the US. We look at the unit, the curb, the roof, the electrical and the controls, then give you a written repair-or-replace recommendation with the costs laid out line by line.

Request an assessment through our quote form. Tell us how many units, their approximate age and what's going wrong.