HVAC repairs can run into the hundreds or thousands of dollars. Being able to recognize and prevent common issues affecting your HVAC system—whether it’s residential or in an office space—will save you a lot of money. Sometimes it’s as simple as a clogged air filter or dirty coil, but other times the issue can be more labor intensive. Check out some of these common problems here.

Lack of Maintenance

Every HVAC system needs routine maintenance to work properly. Some maintenance tasks, such as changing the filters or relighting the pilot light, are easy enough to do on your own, but you’ll need to hire someone for other tasks. Whether it’s in a residence or business, your furnace needs an annual inspection; be sure to enlist the help of a licensed contractor.

Odd Noises

Are you hearing odd noises coming from your furnace or air conditioner? There should be some sounds, but anything that sounds abnormal, such as rattling or squealing, is cause for concern. Usually, rattling noises signify a loose part, and squealing sounds could indicate a failed motor or blower.

Malfunctioning Thermostat

Sometimes, the issue doesn’t have anything to do with the HVAC unit itself: the thermostat may be the culprit. It might not be in the correct setting; it could be in the wrong mode; or the battery may have died. Check the manual and troubleshoot the easiest solutions before reaching out to a professional.

Lower Efficiency

HVAC problems aren’t always obvious. If you’ve noticed the system is less efficient than it used to be, that could indicate one of many issues. Again, check the easy solutions first; the air filters might need replaced, or a register could have a blockage. If you can’t find an obvious cause, you’ll have to reach out to a professional for repairs.

Not all common issues affecting your HVAC system are small; some could require extensive work. In larger buildings such as apartment or office buildings, you can use airflow meters to detect larger-scale problems before they become expensive issues.