The short answer: commercial HVAC should be serviced at least twice a year — once in spring before cooling, once in fall before heating — with filters changed every one to three months. But "twice a year" hides a lot of nuance, because a chiller, a boiler, and a cooling tower each have their own rhythm. Here's the complete frequency guide for every piece of equipment in a GTA building.
The simple rule: two seasonal visits, minimum
Commercial HVAC equipment is stressed most at two moments in the year: the first hot week of summer and the first cold snap of winter. The entire logic of a maintenance program is to inspect and prepare equipment before each of those moments, not during them.
- Spring visit (April–May): prepares cooling equipment — chillers, rooftop units, cooling towers, condensers — before summer load.
- Fall visit (September–October): prepares heating equipment — boilers, gas heat sections, hydronic loops — before winter.
Skip one, and you send half your equipment into its hardest season uninspected. That's the single clearest predictor of an emergency callout.
The complete frequency table by equipment
Here's how often each major piece of commercial HVAC equipment should actually be serviced:
| Equipment | Service frequency |
|---|---|
| Air filters | Every 1–3 months |
| Rooftop units (RTUs) | 2× / year + filters |
| Boilers | 1–2× / year + annual TSSA |
| Chillers | 2× / year (startup + shutdown) |
| Cooling towers | Continuous water treatment + seasonal clean |
| Fan coil units | 2× / year + filters |
| Air handling units (AHUs) | 2× / year |
| Pumps & VFDs | 1–2× / year |
| Generators | Monthly test + annual load bank |
| Building automation system | Annual calibration |
When twice a year isn't enough
Some buildings and equipment need more. Step up to quarterly (or more frequent filter changes) if:
- The building is near construction, industry, or a dusty environment — coils and filters foul fast.
- It's a restaurant or has grease-laden exhaust — rooftop units clog quickly.
- The equipment is mission-critical — data rooms, medical spaces, anything where a failure is a crisis.
- The equipment is aging — older units need closer watching as they enter the failure curve.
- You have a history of frequent breakdowns — more frequent service breaks the reactive cycle.
Scheduled visits catch problems on a calendar. But equipment doesn't fail on a calendar. The buildings with the fewest emergencies pair twice-yearly service with continuous monitoring — so a reading drifting out of range in July pings someone that day, instead of waiting for the October visit. Scheduled maintenance plus live monitoring is how you get from "fewer breakdowns" to "almost none."
What happens if you don't maintain it
Deferred maintenance isn't saving money — it's deferring a bigger bill. The predictable consequences:
- Higher energy bills — dirty coils and clogged filters make equipment work harder for the same output.
- More breakdowns — small issues compound into failures, usually at the worst time.
- Voided warranties — most manufacturers require documented maintenance to honour warranty claims.
- Premature replacement — unmaintained equipment reaches end of life years early.
- Comfort complaints and liability — the resident or tenant calls, and now it's a reputation problem too.
The cost of a maintenance program is almost always a small fraction of the cost of the failures it prevents. That's the entire case for preventive maintenance in one sentence.
Not sure your building is on the right schedule? We'll review it free.
Send us your building's equipment list and current maintenance program. We'll return a written review within 48 hours — gaps, under-serviced equipment, and the right cadence for your building. No pitch, no obligation.
Request a Free Review →Frequently Asked Questions
How often should commercial HVAC be serviced?
At least twice a year — spring before cooling and fall before heating — with filters changed every 1–3 months. Critical, high-use, or aging equipment and dusty environments benefit from quarterly service.
Is twice-a-year HVAC maintenance really necessary?
Yes. The spring visit prepares cooling equipment before summer; the fall visit prepares heating equipment before winter. Skipping one sends half your equipment into its hardest season uninspected — the clearest predictor of emergency callouts.
How often should commercial HVAC filters be changed?
Every 1–3 months. Monthly for high-use spaces, restaurants, and dusty environments. Clean filters are the cheapest way to protect equipment, capacity, and energy use.
What happens if you don't maintain commercial HVAC?
Higher energy bills, more breakdowns, voided warranties, and premature failure. A dirty coil or worn belt caught in service costs little; left alone it becomes a multi-thousand-dollar compressor or heat exchanger failure.