We often take for granted the air within our buildings. It just magically gets the environment cool or warm. More commonly, maintenance is not done in an effort to save money; however, forgoing maintenance can actually cost you more on your utility bills. Ignore it and you will degrade the efficiency of the system.
Furthermore, a properly maintained system will provide better comfort for the occupants. Here are a few recommendations:
Periodically check your thermostats. The easiest thing to do is to make sure that you have a thermostat that allows you to program a schedule based on when your building is occupied.
- Set back the temperature during the unoccupied time along with setting the fan to “Auto” during the unoccupied time.
- Make sure that it is programmed correctly; and that it is not on a constant override.
- If your thermostat temperature sensor needs to be calibrated, double check the readout of the temperature relative to a thermometer place it next to the thermostat. I have seen thermostats that need to be calibrated that are struggling to condition a building when the temperature is fully satisfied.
Belts driving the supply fan are common in many commercial buildings. Belt tension should be checked periodically and changed out at least once a year.
- We have metered the supply fans on rooftop package units and watched them over a span of several years. We can tell from our watt readings when the belts start to wear; and the motor starts to slow down. This typically happens around the 1-year mark. We have seen motor watts decrease around 30%. When you translate that to what is actually happening to the blower, it becomes apparent that there is less air being delivered to the conditioned space.
- This scenario could ultimately cost you more money through prolonged “on” time of the heating or cooling as the conditioned air is not going to be blown as far into the room; as well as not having the proper velocity to do the proper transfer of heat to the delivery system from the heat exchanger or evaporator coil.
Be sure to regularly maintain and change your air filters. These can be as frequent as every month or as infrequent as twice a year. This is all dependent on your building’s surroundings and internal building environment.
I have seen a dusty interior environment that necessitated a change out of filters once a month.
Outdoor environment can also impact your air filter as most systems pull in some outdoor air due to building code standards.
- Check your air filters often until you understand the schedule that would be best for your filters.
- The impact of a dirty air filter is that you willnot be able to draw enough air to be pushed through your system.
- This impacts the comfort of the building as there will be less conditioned air to be distributed.
- This can also lead to a service call during the summer where it could lead to iced up coils. So, avoid an unnecessary call to your HVAC contractor and get on a regular maintenance schedule for yourair filters.
Your outdoor condensers will also need to be cleaned at least once a year at a minimum. If you live in an area where there is a lot of dust and foreign material, such as cotton wood, it may be necessary to clean them twice during your cooling season.
- Keeping your outdoor condensers clean will help make sure that your refrigeration system is working as efficiently as it can.
- A dirty filter will lead to a service call when your system can not keep up during the hottest day during the summer time. This could lead to a comfort complaint or a high limit switch-tripping which will shut the unit off. Who wants that in a heat wave?
- It is also good practice to occasionally clean your evaporator coil to keep the heat exchanger as efficient as possible. Check your evaporator yearly to assess whether or not it will need a cleaning.
Before the start of the summer cooling season, some of these items can be taken care of at the same time as a system check. Have your HVAC contractor hook up gauges to the refrigeration system in order to confirm that the system is properly charged and ready for the hottest day of the summer; along with trouble shooting any potential leaks. Many of these preventative maintenance measures can be planned ahead of time to minimize the costs and number of trips for your HVAC contractor. It is a good to develop a maintenance plan with your contractor to help maximize comfort along with minimizing energy consumption. Happy HVAC-maintenance; and have a comfortable rest of your summer!
Paul Lin has worked in the electric motor industry for most of his professional career. He has worked in manufacturing, design engineering, application engineering, marketing in helping many of the HVAC OEM’s integrate the latest motor technologies into their systems. Paul has also worked with the Department of Energy, utilities, and other organizations in advancing minimum efficiency standards through state and federal regulations as well as through utility incentives.