Dirty Filters: A Minor Issue that Causes Major Damage to HVAC Systems

HVAC heating and air conditioning residential units

Air conditioners and furnaces need continuous and adequate airflow to work. Problems start to develop when the filter gets so dirty it blocks not only debris but also the cooled or heated air. It doesn’t stop there, though. ENERGY STAR, the energy efficiency resource center of the Department of Energy, says dirty filters can damage HVAC equipment and lead to early failure.

Damage to Air Conditioning Systems

When a clogged filter restricts the air passage, the first casualty in an AC is the heat pump’s evaporator coil. Under normal circumstances, the refrigerant absorbs heat from the warm air that passes through the coil, cooling the air before the fan blows it through the vent. Without warm air, the refrigerant cannot regulate its temperature. It will soon fall below freezing point, turning residual moisture in the surrounding air into ice. If left unnoticed, the evaporator coil could fail, defrost by default, and cause water damage.

Damage in Furnaces

Clogged filters also damage furnaces in the long run. Furnaces contain automatic limit switches that turn off the burners when the temperature climbs at a certain level. As a clogged filter blocks the hot air from exiting the heat exchanger, the furnace’s temperature rises faster and activates the limit switch earlier than necessary.

The heating cycle, thus, gets shorter and becomes more frequent. The wear and tear rate of the limit switch and other connected components like the burner, thermostat, and blower fan will increase. Homeowners will also notice that although their heater runs, it doesn’t generate adequate heat. Superior Heating and Cooling, an HVAC company that repairs furnaces in St. Charles, Missouri, says this is a sign that a heater needs professional attention.

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A Chump Change that Equals Thousands in Savings

Timely replacement of filters is the best way to protect HVAC systems from damage. Filters cost around $15-30, which is chump change in comparison to repair and replacement costs. Home Advisor estimates the average price of a furnace at about $4,212 in 2018.

Overlooking AC filters in routine checks can have costly outcomes. Homeowners must pay them more attention and make sure their HVAC maintenance technicians do as well.