7 common commercial HVAC problems and how to resolve them

Plus, how to improve reliability, save money and avoid breakdowns

Every business needs a strong, reliable HVAC system to keep its customers happy and its workers productive.
Customers leave, tenants complain and employees grumble when a business lacks a steady stream of heating, ventilation and air conditioning.
A commercial HVAC system also must be energy-efficient, which helps the business maintain a healthy bottom line and reduces stress on the environment.
Cost is certainly a consideration for any business that wants to hold the line on overhead.
“Space cooling accounts for roughly 15% of electricity used in commercial buildings -- second only to lighting,” says energy.gov, a branch of the U.S. Environmental Protection Agency.

Big differences between home and commercial HVAC systems

Some people mistakenly assume a commercial HVAC system is simply a bigger version of a residential HVAC system.
Commercial systems cover much bigger areas than the average home and must meet a variety of demands.
Imagine a restaurant, a medical facility or an office building. All have very different HVAC requirements from the typical residence – and from each other!
That’s why each commercial HVAC system requires multiple thermostats, considerably more wiring and powerful systems.
• More differences: Commercial spaces often have higher roofs and much more foot traffic than homes – factors the HVAC must accommodate.
Bottom line: To meet the needs of a business, a commercial HVAC operation may cost 150% to 200% more than a residential HVAC system.
• Another difference is location.
A residential HVAC system may be placed in a side yard, for example, but a commercial HVAC system often functions best on a roof. This saves space, reduces noise and serves as a perfect solution for maintenance – the business continues undisturbed when technicians are working on it.

7 commercial HVAC problems

Common problems in commercial HVAC often revolve around maintenance.
They can be avoided or minimized by diligently checking the system.
One example, filters should be cleaned or replaced periodically. Otherwise they become clogged and lead to problems – under-functioning HVAC and poorer air quality.

1. Evaporator coils frozen

Dirty air filters are often Suspect No. 1 when your evaporator coils freeze.
Look next at the refrigerant level and determine if it is too low. This could indicate a leak in a refrigerant line.

2. Fuse blown

Don’t simply flip the breaker back on, especially if blown fuses become common. A blown fuse could indicate that it has stopped protecting your compressor and motor from overheating.

3. Blower runs constantly

You may have a stuck fan if the blower runs nonstop and the thermostat is on the “auto” position.

4. Thermostat issues

Most thermostat problems are quick fixes. Batteries may wear out or users may accidentally turn them off or fail to set them correctly.

5. Compressor leak

When a compressor starts running much louder than usual, it may be warning you of a refrigerant leak.

6. Dirt on condenser coils

When they become dirty, condenser coils reduce the airflow inside your business

7. Burner inefficiency

Rust particles, soot and other debris can build up on the heat exchangers, reducing the burner’s efficiency and making the system work harder.

Maintenance saves

It’s important that maintenance checks are made periodically – either by the building’s staff or by a professional contractor -- to make sure small problems are caught and corrected quickly.
Some issues, however, are more complicated and can cause a commercial HVAC failure. Without quick, smart action, they can cause significant, expensive heating or cooling problems.

Compressor problems

The compressor, often the most expensive component, relies on other parts of the system to keep heat, air-cooling and ventilation in order.
When refrigerant gets low, the compressor will operate sluggishly and may overheat.
Whenever refrigerant is involved, call a certified technician. Federal law requires a license for handling units that contain refrigerant chemicals, which can lead to toxicity, flammability and asphyxiation.

Snowballing problems

When neglected, small problems grow into big problems.
For example, a compressor’s efficiency will be undercut by dirty coils, dirty filters and broken parts.
Because the dirt makes the compressor work harder, chances of overheating increase. And excessively hard work cuts the unit’s life expectancy.

More HVAC problems & solutions

Every commercial HVAC trouble-shooting guide recommends regular maintenance to clean, check and lubricate parts.

More suggestions:
Aging ducts: Over time, ducts tend to develop leaks or be dislodged by vibrations and rodents. Then, some of the treated air escapes before it reaches the inside rooms it is supposed to heat or cool.
Damaged ducts make the system work harder to compensate for the flaws.
A pressure test often can determine if there’s a problem.
Noisy belts: Belts can vibrate loose, especially if they serve the evaporator. This leads to slower fan rotation. Commercial HVAC belts make noise when they get loose – just like an automobile fan belt -- and aren’t difficult to fix.
Evaporator problems: Many heating and air conditioning problems can be traced to the evaporator, a key part of the system.
It helps remove hot air from the building, thanks to evaporator coils filled with refrigerant. These coils are very cold; the refrigerant soaks up the warm air and moisture, helping to lower the humidity and cool the building.
But refrigerant can leak from the coils, and the building won’t have enough cooling. Common clues: Unusually high utility bills, a frozen evaporator coil, icy refrigerant lines, unusual noises in the refrigerant lines.
Low airflow: Without enough airflow, a system can freeze over. You need to act quickly on this issue because it can affect the compressor.
Low airflow often is due to dirty filters or closed vents. (Even vents in unused rooms should be kept open to keep the airflow on an even keel.).
A building’s maintenance staff or a contractor should regularly replace dirty filters, clean evaporator coils and look for leaks.
Air handler concerns: The air handler’s job is to circulate and condition the air.
Common air handler problems include dirt, a breakdown of the blower motor, or failure of a related piece of equipment, or obstructions in the condensation drain line, or reduced airflow.
If the blower motor itself is OK, the problem may lie in the control board, a capacitor or a bad relay.
Puddles on the roof: Make rooftop checks part of your maintenance routine. HVAC units generate condensation, which results in puddles of water that need to be mopped up.

An energy-saving tool

Newer air-handlers include an “economizer,” an energy-saving device. It uses cool outdoor air to cool the building instead of operating the air conditioning compressor.
Its use is limited by the season, the temperature and humidity, all gauged by sensors.
When the outdoor air hits a favorable temperature, the economizer turns on and the air conditioning turns off. The economizer, which requires less energy, cools the building – meaning you enjoy some free air conditioning!
Here again, dirt may prevent the economizer from reaching its full potential. Because it’s part of the outside unit, the economizer should be cleaned periodically.

New commercial HVAC

Older commercial HVAC systems can’t compete with newer, technologically improved systems. Today’s commercial HVAC systems are far more energy efficient and less vulnerable to breakdown.
A cost comparison may show that a new system can be more economical in the long run than an aging commercial HVAC.
• Improved energy efficiency, which will hold the line on utility bills
• Fewer maintenance costs; the new system will be under warranty.

Planning is essential

Since there’s no one-size-fits-all commercial HVAC system, in-depth consideration must go into planning installation and service.
Planning should consider the intricacies of thermostats, compressors, furnaces, duct systems, refrigerants and other issues.
Ventilation has always been a concern, but interest in air quality has increased due to Covid-19, so vents, airflow and filtering warrant extra attention.
Poor indoor quality can be caused by a common air handler problem – dirt, water or rodents infiltrating a blower compartment.
Other key factors: the variety of needs for the business and the amount of power required for a system to function well.
Most commercial HVAC problems can be avoided with smart planning, proper installation and regular cleaning and inspection.


Planners for a commercial HVAC installation must first examine how the building will be used.
• Are you planning large open areas or smaller spaces?
• Will the building be used 9 to 5 weekdays or 24/7?
• Residential users?
• Do products need special temperatures and humidity controls?
All these issues involve mechanisms, systems, equipment, drainage and other factors, making commercial HVAC a very complicated yet vital part of a company’s success.
Another issue: Does the business prefer ductless or ducted HVAC? Each system has pros and cons.

Right size matters

A commercial HVAC system should be chosen on the basis of need, not simply size.
Proper planning will include studies to determine the best fit. If the unit is too small, it obviously won’t do the job. If it’s too big, it will be wasteful.
Many commercial HVAC systems are too large, making them counterproductive.
“According to the Consortium of Energy Efficiency, at least 25% of all rooftop HVAC units are oversized, resulting in increased energy costs and equipment wear. Properly sized equipment dramatically cuts energy costs, increases the life of the equipment, and reduces pollution.”

Unit’s life expectancy

For budgeting purposes, you can expect a commercial HVAC system to last 15 t0 20 years.
That number depends on installation, maintenance and other factors.

Commercial furnaces

Most authorities say a commercial furnace will last 18 years or longer, depending on components, use and maintenance.
Watch for cracks and rust, which can get blown into the air when you turn on the heat.
Another sign of poor aging: The furnace heats the building unevenly, too hot here and too cool there.


Planners for a commercial HVAC installation must first examine how the building will be used.
• Are you planning large open areas or smaller spaces?
• Will the building be used 9 to 5 weekdays or 24/7?
• Residential users?
• Do products need special temperatures and humidity controls?
All these issues involve mechanisms, systems, equipment, drainage and other factors, making commercial HVAC a very complicated yet vital part of a company’s success.
Another major issue: Does the business prefer ductless or ducted HVAC? Each system has pros and cons.

Energy-saving option
You may want to consider ENERGY STAR certified light commercial equipment, which meets federal requirements to reduce energy waste and save money on utility bills.
ENERGY STAR says certified light commercial HVAC equipment is about 6 percent more efficient that other equipment and can save more than $2,000 over its life.

Premier HVAC, a locally owned company, installs, repairs and services both commercial and residential HVAC systems.
Premier serves Brooklyn, Queens, Manhattan and Long Island, and guarantees all its work.
Emergency service available 24/7.
Premier HVAC (718) 790-4446