Most commercial rooftop units in Wheeling and Des Plaines don’t die of old age. They die of neglect — a plugged condensate pan that rusts out a coil, a belt that shreds and takes a bearing with it, a contactor that welds shut in August. Nearly all of it is preventable, and the prevention costs a fraction of the failure.
If you own or manage a strip center, warehouse, restaurant, medical office, or light industrial building, here is how to think about a rooftop unit (RTU) preventive maintenance program: what should be in it, what it costs, and what it actually saves.
What a Real PM Program Includes
“Maintenance contract” means very different things depending on who’s selling it. A cheap contract is two filter changes a year. A real program is a scheduled inspection with measured readings, documented findings, and a plan.
Spring visit (cooling readiness)
- Coil cleaning — condenser and evaporator, chemically when needed
- Refrigerant charge verified by superheat/subcooling, not by gauge pressure alone
- Compressor amp draw compared to nameplate
- Contactor, capacitor, and relay inspection; replace pitted contactors before they weld
- Condensate pan, trap, and drain line cleared and treated
- Belt tension and alignment; bearing lubrication
- Economizer operation and damper linkage — the single most-neglected component on any RTU
- Filter change, curb and cabinet inspection, roof penetration seals
Fall visit (heating readiness)
- Heat exchanger inspection for cracks and corrosion
- Combustion analysis and gas pressure verification
- Ignition system, flame sensor, rollout and limit switch testing
- Inducer and flue integrity
- Controls and thermostat schedule verification
- Filter change and belt re-check
What separates a good contract from a bad one
- Written readings per unit — amps, temperature splits, static pressure, subcooling. Numbers over checkmarks.
- Asset tagging so you have model, serial, tonnage, and age history for every unit on the roof
- Priority dispatch and discounted labor for contract customers
- Capital planning — an annual “these three units are 18+ years old, budget accordingly” memo
What It Costs in 2026
| Program level | Per RTU per year | What’s included |
|---|---|---|
| Basic (2 visits) | $350 – $600 | Inspection, filters, belts, coil rinse |
| Standard (2 visits + quarterly filters) | $600 – $1,100 | Above, plus chemical coil cleaning, priority dispatch, labor discount |
| Full coverage (parts included) | $1,100 – $2,400 | Above, plus covered wear parts (contactors, capacitors, belts, motors) |
| Restaurant / high-runtime add-on | +$250 – $700 | Quarterly visits, hood/make-up air balance check |
Pricing scales with tonnage, roof access difficulty, and unit count. A ten-unit strip center at the standard level typically lands between $7,000 and $10,000 a year.
The costs you’re avoiding
| Failure | Typical emergency cost | Preventable? |
|---|---|---|
| Compressor replacement | $3,200 – $9,500 | Usually — most compressor deaths trace to dirty coils or low charge |
| Evaporator coil replacement | $2,400 – $6,000 | Often — condensate corrosion |
| Blower motor + belt failure | $900 – $2,800 | Yes |
| Cracked heat exchanger (unit condemned) | Full replacement | Detected early with annual combustion inspection |
| After-hours emergency call | $450 – $900 before parts | — |
| Full RTU replacement, 5–25 ton | $9,000 – $80,000 | Deferred by 3–7 years with good PM |
One avoided compressor failure pays for several years of maintenance on that unit. That’s the entire business case, and it’s not a subtle one.
The Economizer Problem
Worth its own section, because it is the most common finding we write up. An economizer brings in outside air for free cooling when conditions allow. When it’s working, a Chicagoland building gets hundreds of hours a year of cooling at fan-power cost only.
In practice, we find broken linkages, disconnected actuators, failed sensors, or dampers wired shut on a majority of unmaintained rooftops. Two failure modes, both expensive:
- Stuck closed: you pay for mechanical cooling in 55°F weather
- Stuck open: you heat outside air all January, and freeze coils
Economizer repair usually runs $400–$1,400 and is one of the fastest-payback items on any commercial roof.
Refrigerant Timing You Should Plan Around
R-22 units are long past phase-out; any remaining R-22 equipment on your roof should be on a replacement plan, not a repair plan, because refrigerant cost alone can exceed the value of the unit. R-410A is now in its own HFC phasedown, with new equipment shifting to lower-GWP refrigerants such as R-454B and R-32. That doesn’t strand your R-410A units — service refrigerant will remain available for years — but it does mean two things:
- Budget for rising R-410A pricing over the life of older units
- When you do replace, expect new-refrigerant equipment with different service requirements and, in some cases, different clearance rules
Building a Multi-Unit Replacement Plan
Commercial RTUs typically last 15–20 years in this climate; restaurant and high-runtime units, closer to 12–15. Once you have asset data from a PM program, capital planning becomes straightforward:
- Inventory every unit with age, tonnage, refrigerant, and condition score
- Triage: replace now (failing or R-22), plan 1–3 years (15+ years old, rising repairs), maintain (under 12 years, healthy)
- Sequence replacements in shoulder season — April–May and September–October. Crane availability is better, tenant disruption is lower, and you’re not paying emergency premiums
- Replace in small batches rather than all at once, so you’re not facing a full-roof capital event in one year
For details on the replacement side, see our commercial HVAC page.
What Tenants and Leases Change
In most northwest-suburban strip centers, the lease puts HVAC maintenance on the tenant and replacement on the landlord — which produces exactly the wrong incentives. Tenants defer maintenance; landlords inherit dead equipment.
The fix landlords increasingly use: the landlord holds a building-wide PM contract and passes the cost through as CAM. It costs the tenant less than an individual contract, the landlord gets documented service history protecting the asset, and there’s one contractor who knows the whole roof.
Frequently Asked Questions
How often should commercial RTUs be serviced?
Twice a year minimum, spring and fall. Restaurants, buildings with heavy grease or dust loads, and units running extended hours should be quarterly.
Does maintenance actually extend equipment life?
Yes, and the mechanism is not mysterious: clean coils lower head pressure, which lowers compressor amp draw and operating temperature. Dirty condensers are the leading cause of premature compressor failure we see on neglected roofs.
Is a parts-included contract worth it?
On units under 12 years old, usually yes. On a roof full of 18-year-old equipment, no — you’re pre-paying for failures on units you should be budgeting to replace instead.
Can you service units another contractor installed?
Yes. We service all major commercial brands regardless of who installed them.
What documentation should I expect?
A per-unit report with measured readings, photos of any deficiency, a written recommendation with pricing, and an updated asset list. If your current provider gives you a signed invoice and nothing else, you’re not getting a PM program.
Get Your Roof Assessed
MMDS provides commercial HVAC maintenance, repair, and replacement for strip centers, restaurants, offices, and light industrial buildings in Wheeling, Des Plaines, and throughout the northwest suburbs. We’ll walk your roof, inventory every unit, and give you a written condition report and a maintenance proposal with real numbers in it.
Call (847) 221-6280 or request a roof assessment. Ask about our maintenance programs for multi-unit properties.