The filter in your furnace is critical to system airflow. Proper airflow, in turn, affects energy efficiency and the comfort level in your home. It also protects the moving parts of your furnace, such as the blower motor, from excessive wear and tear caused by dust intake. Finally, a quality furnace filter removes airborne particulates from the breathing air in your home. These include allergens like dust and pollen as well as microorganisms such as mold spores.
The efficiency of furnace filters is ranked according to the filter’s Minimum Efficiency Reporting Value (MERV) rating. The higher the MERV number, the more particulates the filter removes from the air. Standard filters rated 1 through 4 ensure optimal airflow, but don’t capture smaller particles. For conventional household use, pleated filters with a MERV 8 rating may provide the best balance between airflow and efficiency. If the home contains residents who are particularly sensitive to airborne particulates, you may want to use a higher-rated filter. However, high-rated MERV filters may also restrict airflow, so it’s best to consult with your HVAC professional or the owner’s manual before doing so.
When a filter clogs, the restricted airflow strains the blower motor and causes the furnace to run longer in order to meet thermostat settings, wasting energy. Reduced airflow means that your living spaces aren’t warmed consistently — particularly rooms furthest away from the furnace. Eventually, a clogged filter may result in air bypass, in which completely unfiltered air infiltrates around the edges of the filter and contaminates the entire system.
Change the filter in your furnace often over the heating season, checking it every month to see if it’s dirty and full. Here’s how it’s done:
- Turn down the thermostat to turn off the furnace.
- Open the service door, normally found on the lower front or side of the furnace.
- Slide the old filter out and dispose.
- Position the replacement filter so the directional arrow printed on the edge points into the furnace and slide it into the filter frame.
- Close the access door.
Since 1993 and with nearly 60 years of combined experience, Cooper Climate Control Heating & Air Conditioning has been the Valley-Metro area’s trusted HVAC sales and service provider. Give us a call at 480-460-7417 for more information on changing the filter in your furnace.