If the system isn’t turned off first, it will suck in debris during the cleaning process. Use a step ladder if the vent is up on the ceiling or a high wall.

Vacuum the filter outside, if possible, to avoid stirring up dust in the home.

Use a gentle spray, not the full force of your hose, to avoid damaging the filter. [7] X Research source

After the final rinse, shake off any excess water before setting the filter out to dry. You may want to wash your filter with a soap solution if it’s been exposed to grease, smoke or pet hair.

Neglecting to let the filter dry completely can cause mold growth, which can spread spores throughout your home through the HVAC.

The filter should sit snugly, without appearing too small or warped. Make sure there are no gaps.

The air filter’s housing should be on top of the engine, in a round or rectangular box.

Vacuuming is faster and safer than washing the filter.

Don’t put the filter back when it’s still wet! This can damage the vehicle’s engine. Washing can get your filter cleaner than vacuuming alone, but is riskier and more time-consuming.

Don’t allow the cleanser to dry on the filter; let it sit only for ten minutes. Rinse the filter by moving it up and down under the stream of water. After the rinse, the filter should be dry in about fifteen minutes; but if it isn’t thoroughly dry, allow it to sit longer. If you’re short on time, you can use a hair dryer or small fan on moderate heat to speed up the drying process, after the rinse stage only.

Moisture and debris can cause damage to the engine.

Washing disposable air filters can actually clog them, as well as cause mold. Disposable filters can tear under the pressure of vacuuming or compressed air. At a low pressure, this may work temporarily, but it’s not a long-term solution.

Disposable filters should be replaced, whereas permanent filters can be vacuumed or washed. If you don’t change your air filter as needed, you may notice a decrease in your gas mileage, ignition problems, or fouled spark plugs.

If your filter is disposable, replace it. If it’s reusable, you can vacuum or wash it. More frequent changing is needed if your filter is exposed to a lot of dust or pet hair. Failing to clean your air filters in the home can cause HVAC failure or even fire.