Expensive Repair Bills Due to Dirty Filters - Why You Need to Regularly Check Your FiltersChanging your HVAC system’s air filter regularly can save you as much as 15 percent on your utility bills by improving the efficiency of your air conditioner or furnace. But that’s not the only reason to change a dirty air filter. Replacing a filter before it’s so dirty that it affects airflow can also spare you expensive repair bills. Here’s how.


Most HVAC systems have air filters that keep dirt and other particles out of the mechanical parts of the furnace, air conditioner or heat pump. A dirty air filter can increase pressure drop, an imbalance in the ductwork on the opposite sides of the filter. When the air pressure imbalance is too great, the HVAC system strains to process the air. Energy is wasted and wear on the parts, particularly the fan motor, is accelerated, as the blower works harder and runs longer to achieve the thermostat set point. Over time, you’ll have to replace parts and repair breakdowns sooner than you would if you’d kept the filter changed.

Dirty air filters also lead to frozen evaporator coils as dirt collects on the coils. Frozen coils impede airflow so that the A/C can’t cool properly. To compensate, you may turn the thermostat lower, but this just causes the A/C to work harder. Overworking the HVAC system in this manner can ultimately cause it to fail before its time.

A dirty air filter may even adversely impact your furnace. Reduced airflow may cause overheating of the heat exchanger so that the unit shuts off too soon and the home isn’t adequately warmed. This can in turn cause electronic “limit switch” failure.

Mold Growth

Dirty filters also are more likely to become damp from condensation, which can lead to the growth of mold. Once mold becomes established in your HVAC system, it can spread to your home, where your air will not only become contaminated, but you’ll need to service your unit to correct the problem.

If you have questions about how a dirty air filter can cause unnecessary repair bills, contact Bradbury Brothers Heating & Air Conditioning of The Woodlands.