Top 10 signs your HVAC system needs maintenance
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Transcript
If your heating, ventilation, and air conditioning (HVAC) system is making odd noises, emitting strange odors, or failing to keep temperatures consistent, it’s not just an inconvenience; it’s a warning sign.
Whether you manage a data center or a downtown office building, catching issues early can save thousands in energy and emergency repair costs.
1. Thermostat readings don’t match the room temperature
When the actual temperature in a room doesn’t match what the thermostat displays, you’ve likely got a calibration problem or worse. Faulty sensors, outdated thermostats, or poor placement (too close to vents or windows) can all throw off readings and cause the HVAC to run when it shouldn’t.
Even a 2-3°F inaccuracy in a large building can spike heating or cooling costs by up to 10%. Comfort complaints follow quickly, and your system racks up unnecessary wear trying to hit an unreachable setpoint.1
2. HVAC system runs constantly or struggles to keep up
If your system never seems to shut off, or it can’t quite hit the set temperature, something’s off. Dirty coils, clogged filters,malfunctioning sensors, or an undersized unit could be the culprit. Any of these makes your HVAC work overtime, and the utility bills show it.
According to the Department of Energy (DOE), poor HVAC maintenance can drive energy use up 5-20% each year. That’s a budget-busting problem in large commercial facilities.2
What needs to happen:
Start with the basics:replace filters, clean coils, and make sure the system is appropriately sized for the space. Schedule regular tune-ups to catch minor issues before they create major energy waste.
3. Occupant comfort complaints or IAQ issues
When staff or tenants say the air feels stale, muggy, or too dry, that’s a red flag. High humidity can cause mold risk, while low humidity leads to dry air and static—both signs of failing dehumidification or ventilation problems.
Beyond discomfort, poor indoor air quality (IAQ) affects productivity and satisfaction,and it can lead to bigger tenant retention issues over time.
What needs to happen:
Replace filters regularly and assess your ventilation and humidity control components. Track complaints to spot patterns and prioritize adjustments that protect occupant health and comfort.
4. Unpleasant odors
When your HVAC starts producing strange smells,it’s time to pay attention. Musty odors may point to mold or mildew in the ducts or drip pans. A burning smell could signal an electrical issue. And any chemical or sweet scent might indicate a refrigerant leak, which is an environmental and safety concern.3
The International Facility Management Association (IFMA) lists odor complaints as one of the top drivers of tenant dissatisfaction. Ignoring the source doesn’t just risk occupant complaints; it may also create health hazards or system damage.
What needs to happen:
Investigate and resolve odor complaints immediately.Schedule a professional inspection to check duct work, drain pans, and electrical components. Mold and refrigerant leaks require a swift, specialized response.
5. Uneven or weak airflow
If some rooms are freezing while others feel like a sauna, airflow is likely to blame.Blocked vents, dirty filters, broken dampers, or aging fans can all disruptcirculation. And when airflow is uneven, your system must work harder to maintain setpoints, leading to higher wear and energy waste.
Inconsistent airflow is also one of the most common reasons for tenant discomfort and maintenance calls.
What needs to happen:
Audit your system for blockages and mechanical failures. Ensure ducts are clear and properly sealed, fans are operational, and dampers are balanced. Include airflow checks in routine maintenance plans.
6. Your HVAC is louder than usual
A low hum is normal. Grinding, screeching, banging, or squealing? Not so much. These sounds often indicate loose belts, failing motors, or compressor trouble. Ifleft unaddressed, these small issues can lead to full mechanical failure or shutdown.
Proactive maintenance can catch these problems early, saving thousands in repairs and preventing costly emergency downtime.
What needs to happen:
Don’t wait for the noise to go away. Schedule a technician to inspect the system, tighten any loose components, and assess whether parts need replacement. Early fixes are always cheaper.
7. Your energy bills are climbing
Energy use should be consistent year-over-year, accounting for seasonal demand. If your utility bills are rising and there’s no change in occupancy or space usage,your HVAC system could be losing efficiency.
Dirty coils, aging motors, or outdated controls can slowly degrade performance and inflate your monthly costs.
What needs to happen:
Benchmark energy use against past data. If you see unexplained increases, inspect your HVAC system. Clean components, optimize controls, and consider a tune-up or retrofit for older equipment.
8. Short cycling or power disruptions
Short cycling (when the system turns on and off frequently without completing a full cycle) can overheat components, strain compressors, and dramatically reduce system lifespan. It also leads to poor temperature control and higher energy consumption.
Causes range from refrigerant issues and faulty sensors to improper system sizing or control failures.
What needs to happen:
If short cycling occurs, have a technician run diagnostics. They'll check for pressure imbalances, control errors, or equipment that is undersized/oversized. Early intervention can prevent a complete system failure.
9. Building layout or occupancy has changed
If you’ve recently added walls, rearranged open office spaces, or made significant floor plan changes, your HVAC system may no longer be optimized for the new layout. Poor airflow, hot spots, or over cooling can all result.
Your system was designed for a specific load and configuration. When the building changes, airflow and ventilation strategies should, too.
What needs to happen:
After significant layout changes, schedule a system assessment. Technicians can re-balance airflow,adjust vent placement, and evaluate if zoning or equipment changes are needed to match the new floor plan.
10. You’re only reacting to breakdowns
A “run-to-fail” approach might seem cost-effective—until it isn’t. Deferred maintenance can lead to catastrophic failures, long lead times on parts, and unhappy building occupants.
What needs to happen:
Shift from reactive to preventive maintenance. Set a regular inspection schedule and partner with a facility services provider who can monitor system health, catch early warning signs, and help plan lifecycle upgrades.
Bonus: Smart alerts give you a head start
Modern commercial HVAC systems now include IoT-enabled sensors that monitor performance in real time. These smart alerts can catch signs of trouble before they affect comfort or drive up your energy bills. Think clogged filters,refrigerant issues, sensor drift, or efficiency loss if all are flagged early.
But even the most innovative systems are only helpful if someone’s watching. Ignored alerts mean missed opportunities and wasted investment.
What needs to happen:
Use your smart alerts as a front line defense. Make sure your building automation system is monitored regularly—either in-house or through a trusted facility services partner like ABM. When an alert fires, act on it quickly to stay ahead of breakdowns and control costs.
Why proactive maintenance matters
- 5-20% savings on energy bills with regular maintenance (DOE)
- Up to 95% fewer breakdowns with a preventive maintenance program4
- Get a 545% ROI on preventive maintenance5
If your commercial HVAC shows any of these signs, a scheduled inspection is cheaper (and far less disruptive) than an emergency repair.
Stay ahead of HVAC issues with ABM
ABM’s expert HVAC technicians work across every commercial sector from office towers and hospitals to manufacturing sites and data centers. We help facilities stay efficient, compliant, and comfortable year-round.
Whether you need a system assessment, seasonal tune-up, or a fully managed preventive maintenance program, ABM can help you optimize performance while reducing long-term costs.
Book your commercial HVAC maintenance inspection today.
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Sources
- dc.gov energy tips commercial buildings
- energy.gov why energy efficiency matters
- epa.gov mold remediation
- jll.com improve your facilities
- micromain.com preventive maintenance study
