2 Ways To Increase Your Furnace's Airflow

During the wintertime, you use your forced-air furnace to keep your home warm and comfortable. In order to efficiently heat your home, your furnace must produce a significant amount of airflow—but without proper maintenance, your furnace will be unable to do just that. To ensure that your furnace operates efficiently throughout the winter, perform these two maintenance tasks:

Replace or Clean Your Air Filter

All airflow throughout your furnace and HVAC system must first pass through your air filter. When air passes through your air filter, dust, dirt, pet fur, and any other airborne debris becomes trapped. Depending on the quality of the air throughout your home, your filter's pores can become clogged in as little as a month. When your air filter is clogged, it will significantly restrict the amount of air that can pass through it.

Your furnace's air filter is located inside of your blower motor compartment on the side connected to your return duct. To replace it, simply open the compartment, pull out your dirty filter, and wipe away any remaining debris with a water-dampened cloth. Don't use any cleaning agents to remove debris from the area surrounding the air filter—chemical cleaners leave behind a flammable residue that may be ignited when you activate your furnace. Once the area around the filter is clean, slide in a replacement filter that's compatible with your furnace system.

If your furnace has an electrostatic air filter (housed in a separate box from your blower motor), then you'll need to clean it rather than replace it. To do so, deactivate the electrostatic filter and open its access door. Inside your electrostatic filter box, you'll see these components:

  • Pre-Filters

    • The pre-filters in your electrostatic filter system trap the large airborne debris present in your home. These filters are located right next to your return duct and can be washed with your garden hose or soaked in a mixture of mild dish soap and warm water.

  • Cells

    • Your cells are the large metal boxes inside your electrostatic filter system. These cells clean bacteria and other minute contaminants present in your home's air. Your cells can be washed the same way as your pre-filters but must be dry completely before being placed back into your filter system since they're conductive.

  • Charcoal Filters

    • The charcoal filters in your filter system are designed to reduce odors. However, not every electrostatic system uses charcoal filters. If there are charcoal filters in your system (small, black screens that look similar to your pre-filters), then replace them whenever you clean your filter system.

Regardless of whether you have a conventional air filter or an electrostatic filter system, you should inspect your filter every month during the winter to determine whether or not it needs to be cleaned or replaced.

Clean Your Blower Motor and Squirrel Cage

The next components that air must pass through before entering your furnace are your squirrel cage (a large, metal drum through which air circulates) and blower motor. Although these components receive air that's already been passed through your air filter, they're still capable of becoming coated in dust and other debris.

However, cleaning these components will require a bit of electrical knowledge. If you're not familiar with the electrical wiring in your furnace, then it's best to leave this maintenance task to your professional HVAC technician.

You'll need to remove your blower motor and squirrel cage from your furnace in order to clean them. To do so, first shut off your furnace's electrical power and gas supply. Inspect the wiring between your blower motor and furnace. Begin carefully disconnecting the wiring and mark each wire connection with labeled pieces of tape to avoid confusion during re-installation. Alternatively, take a picture of your furnace's wiring before performing any work.

Once your wiring is disconnected, remove the mounting bolts from the base of your squirrel cage and pull both your cage and motor out from your blower motor compartment. Separate your motor from your squirrel cage by removing the three or four bolts around the interior of your cage. Thoroughly wash all debris inside your squirrel cage with your garden hose.

To clean your blower motor, use a gas duster or air compressor to blast away any debris from the interior and exterior of the housing. If you use a gas duster, make sure not to invert the can—otherwise, you may damage your motor's internal electronics. After your squirrel cage and motor are clean of debris, you can reinstall them back into your blower motor compartment and test your furnace.

If you encounter difficulty while performing either of these maintenance tasks, then hire a heating service technician to finish the job for you. By doing so, you can ensure that your furnace will operate safely throughout the entire winter season.