You can clean and reuse a permanent HEPA filter, but it must be done with utmost care to avoid damaging it. Most permanent HEPA filters can be gently vacuumed, while a washable HEPA filter can be cleaned by rinsing it with cold water. Note that there are no officially defined standards or terms as to what type is considered permanent or washable. If you're not sure if the HEPA filter can be cleaned, look for the “washable” or “permanent” label on the packaging box or on the air cleaner's website.
If you notice a visible accumulation of dust or particles on a HEPA filter (it may look gray or dirty) or you notice a reduction in airflow through your portable air purifier, it is an indication that the HEPA filter needs cleaning. However, experts suggest that HEPA filters should always be replaced rather than cleaned. If the filter is marketed as washable or permanent, you may be able to wash or clean it and it will continue to work. But there is no standard for washable HEPA filters, and there have been no public studies to prove how well these filters work after being washed.
The manufacturer may have found a method to make filter fibers that won't be damaged by cleaning, but there's really no way to know for sure, so you take a risk. While a genuine HEPA filter will remove 99.97 percent of air pollutants, a washable filter will remove 90 to 95 percent of these same particles. Some of the materials used to produce HEPA filters include synthetic fibers (usually durable polyester or nylon) and artificial foam. To comply with the HEPA standard, a filter is estimated to remove 99.97 percent of particles that are 0.3 microns (or microns) in size from the air passing through them. Air ionizers and ozone generators don't use filters, so there's nothing to clean and reuse.
A HEPA filter marketed as “permanent” should be gently cleaned with a vacuum to vacuum dust and dirt from the filter surface. Turn off the appliance and follow the manufacturer's instructions carefully for removing the filters. The first thing you'll notice is that the HEPA filter isn't the only filter that requires cleaning. This is a specialized air filter that puts tons of activated carbon into operation during air purification, consuming smoke and odors quite effectively. Electrostatic filters and activated carbon filters can normally be cleaned and reused, as can some HEPA-type filters.
Over time, the air cleaning capacity of a device decreases regardless of how often you clean the filter. For example, some cartridge type vacuum filters should only be washed on the outside of the filter, taking care to prevent the central part of the container from getting wet. Not all HEPA filters can be washed, and some HEPA filters will need to be replaced after four months or a year. That's why these air filters are so effective at removing health-threatening airborne particles and remain suspended in the indoor air of every American home. The filter frame can be made of various materials, such as cardboard, wood, plastic, or even metal.
