How To Clean Your Electrostatic Furnace Filter

Unlike the standard forced-air furnace, your furnace uses an electrostatic filter to clean your home's indoor air. Although your electrostatic filter provides significant improvements in air quality over a conventional furnace filter, it also requires more maintenance—and without any HVAC training, servicing your electrostatic system may seem impossible. However, your electrostatic system isn't as complicated as you may think. Maintain your electrostatic filter by following these furnace service steps.

How Your Electrostatic System Works

To understand how cleaning your electrostatic filter will improve the efficiency of your HVAC system, you must first learn how your filter system works.

Your electrostatic filter is made of three components: cells, prefilters, and charcoal filters. When your blower motor activates and begins pulling air through your filter, any large airborne debris (such as dust, dirt, or pet fur) is trapped into your prefilters. The air then passes through your electrically-charged cells. When small debris particles (such as bacteria and pollen) enter your cells, the electrostatic field in your cells traps and neutralizes the particles. Upon exiting your cells, any remaining odor in the air is neutralized by your charcoal filters.

After hundreds of hours of use, your prefilters can become clogged and restrict the airflow in the rest of your filter and HVAC system. Debris that manages to slip through your prefilters will dirty your cells and reduce their efficiency. Additionally, your charcoal filters will eventually become unable to remove the foul odors present in your indoor air.

Remove Your Components

To begin servicing your electrostatic filter system, turn off the power to your system and wait a couple minutes for the electrostatic charge in your cells to dissipate. Open the access door on your filter housing and pull out your prefilters, cells, and charcoal filters. Take note of how your cells are positioned before removing them—if your cells aren't reinstalled in their original position and direction, then your system won't work properly.

Wash Your Cells and Prefilters

Luckily, you won't need any chemical cleaners to wash your cells and prefilters. Instead, use a mixture of warm water and mild dish soap. Use about half a cup of dish soap for each gallon of water to ensure a thorough cleaning.

Fill your bathtub or kitchen sink with your soap solution and place your cells and prefilters into the solution. Let them soak for five minutes before removing them and spraying them with your garden hose. Make sure the water pressure through your hose isn't too powerful. If there's too much pressure, then the water blasting out of your hose is likely to bend your prefilters or damage your cells. After washing off your soap solution, let your cells and prefilters air dry.

Replace Your Charcoal Filters

Unfortunately, your charcoal filters cannot be washed. Instead, they must be replaced. Contact your system's manufacturer for replacement filters or find compatible charcoal filters at your local home improvement store. You can slide your replacement charcoal filters into your electrostatic system while your cells and prefilters are drying.

Reinstall Your Components

Once your components are dry, guide your prefilters back into their slots inside your electrostatic filter housing. Position your cells in their original direction and slide them back into your filter housing. Depending on your specific housing, you may need to slide your cells along the grooves or ridges on the base of your housing. Once your components are reinstalled, close your access door.

Test Your Work

Restore the power supply to your electrostatic system and activate your furnace. If your components were properly cleaned and reinstalled, you'll notice a significant improvement in the quality of your indoor air. Monitor the cleanliness of your system over the next few weeks and perform another cleaning when necessary. Continue cleaning your filter system at a regular interval to ensure consistent operation.

If your system doesn't work properly after performing your cleaning, or if you have difficulty at any step in the cleaning process, then hire a professional HVAC technician to inspect and service your electrostatic filter system.