Commercial HVAC systems are built to keep up with heavy use, but that doesn’t make them maintenance free. It’s easy to assume everything’s working fine when the air is cool and steady, but small problems can show up just before seasons change. Heading into the cooler months, keeping an eye on how your system behaves could save you from a headache later.
Commercial AC unit maintenance isn’t always about fixing a big issue. It’s about catching the small signs that something’s off before it grows into a costly problem. Recognizing those signs early can help maintain steady comfort, prevent energy waste, and reduce stress for building managers during the heating season.
Unusual Noises or Vibrations
If a system that usually runs quietly starts making noise, it’s often a red flag. While some sounds might be harmless, others mean the system is straining.
• Rattling noises during startup or shutdown can point to loose panels, parts, or mounts
• Humming might suggest an issue with the motor, especially if the sound gets louder over time
• Grinding usually means there’s a failing bearing or belt that needs to be replaced
Vibrations are another sign that something’s not quite right, especially in rooftop or closet installed commercial units. If a unit starts shaking or humming through the walls or ceiling, it’s smart to schedule a maintenance check before it leads to permanent wear.
Inconsistent Airflow or Uneven Temperatures
When some rooms feel perfect and others don’t, it often means air isn’t moving properly. One system should be able to keep temperatures consistent across zones if everything’s working as it should.
• A blocked filter or clogged coil might be stopping air from flowing freely
• Leaky ducts can let conditioned air escape before it reaches its destination
• Dampers that aren’t aligned or responding can shift airflow unevenly across the building
Temperature swings between rooms usually don’t fix themselves. If a zone never seems to reach its setpoint, that could show up as longer run times, higher bills, and a whole lot of discomfort. Fall is a smart time to get that checked out before cold weather stretches your system even more.
Odors Coming from Vents
Sometimes the nose picks up what the eyes can’t see. If unpleasant smells are coming through the vents, there may be something building up inside the system.
• Musty smells could mean mold inside the filters or drain pans
• Sharp, chemical like odors might point to a refrigerant leak
• Stale air could come from poor ventilation or sitting moisture in the coils
These kinds of smells won’t only make people uncomfortable, they may point to problems that could get worse over time. During commercial AC unit maintenance, filters, coils, and pans are usually cleaned or checked to keep airflow fresh. Catching those odors early makes it easier to avoid long term damage and address any air quality issues lurking in the ducts.
Higher Energy Use Without Noticeable Heating or Cooling
Sometimes the clearest warning sign is the power bill. If the building’s energy use climbs in October but nobody’s touched the thermostat, something may be forcing the system to overwork.
• Filters that need changing can choke airflow, making the fan push harder than it should
• Old compressors pull more power as they wear out, often cycling more to get the same result
• Refrigerant that’s lost pressure can throw off balance and reduce cooling output
Fall is often when these issues first appear. If your system is trying to keep up as outdoor temperatures shift, but it doesn’t seem to cool like before, the equipment may be stuck running longer hours. Checking before the real cold hits gives you more time to fix the source of the inefficiency.
When the Thermostat Can’t Keep Up
Any delay between what the thermostat says and what people feel in the room is something worth noting. If setpoints aren’t being met, it could be a small fix or a sign of a larger issue.
• Old or misaligned sensors might be sending bad signals to the unit
• Electrical issues in the actuator can cause the system to short cycle or run out of rhythm
• If the fan or coils are dirty, the system might run too long without producing effective heating or cooling
Even when the thermostat seems to respond right, the system may keep running without reaching the desired temperature. When this happens, it’s best to pause and find out what’s causing the breakdown before it turns into a deeper system fault.
Built for Demanding Workloads and Trusted Performance
Routine checks and quick responses to early signs help keep HVAC systems operating smoothly and extend their service life. At AE Air, every chilled water fan coil unit and water source heat pump is engineered for heavy-duty commercial use. These units are designed to provide optimal performance and energy efficiency in large commercial buildings through seasonal changes.
By maintaining equipment that is built to support demanding workloads, building teams support occupant comfort and building efficiency year-round while reducing risk of breakdowns during shifts in weather.
Keep Indoor Comfort on Track this Fall
A well running system doesn’t just show up in full operation, it builds on months of steady care. Fall brings its own demands, and AC systems that worked fine in summer might show signs of strain as daily rhythms shift.
Commercial AC unit maintenance doesn’t have to be reactive. It’s often much simpler to catch these warning signs now, during the seasonal transition period, when teams have time to clean, inspect, and reset key parts. A few adjustments can help your equipment deliver strong performance into winter, while keeping energy use stable and comfort consistent throughout the building.
Paying attention early catches small problems before they snowball. It leaves building teams with fewer surprises later and creates peace of mind for tenants and owners alike as cold weather approaches.
When your building’s system is showing signs like inconsistent airflow, odd smells, or rising energy use, now is a good time to have it checked before winter sets in. Small issues often point to bigger problems that can impact comfort and performance when demand increases. Staying ahead with routine care helps support energy efficient building operations across every season. Learn how AE Air supports smoother planning and smarter system performance through ongoing commercial AC unit maintenance. Contact us to schedule a review for your next project.
