When it comes to air purifiers, the general rule is that replaceable HEPA filters should be changed every 6 to 12 months, depending on air quality and environmental factors. Carbon prefilters, on the other hand, should be replaced every 3 months. Most air purifiers have notifications that tell you when it's time to change the filter. If you notice a visible buildup of dust or particles on a HEPA filter (it may look gray or dirty) or a decrease in air flow through your portable air purifier, it's likely time to replace the filter.
Experts recommend replacing the filter rather than trying to clean it. The length of time it takes to replace an air purifier filter depends on usage, size, and environment. Carbon filters tend to last longer than HEPA filters. The HEPA filter traps particles as small as 0.3 microns in size.
In the 1960s, HEPA filters were already being used in hospitals to help stop the spread of germs and particulates in the air, and soon after, they began to appear in appliances such as vacuums, air purifiers, and whole-house air filtration systems. Most manufacturers offer a recommended change interval (usually around six to 12 months), and some portable air purifiers have an indicator light that tells you when you should replace the HEPA filter. A HEPA filter labeled “True HEPA” or “Absolute HEPA” has been tested and meets high efficiency criteria. According to the EPA Guide to Home Air Filters, using HEPA air filters in portable air purifiers and HVAC systems can help reduce allergy and asthma symptoms. Allergens enter the home through open doors and windows, so a single drafty window can let millions of suspended particles in. Keep in mind that HEPA filters trap particles throughout the fabric, not just on the surface.
This network of fibers captures small particles and filters them from the air you breathe, ultimately helping improve indoor air quality. In an attempt to control COVID-19 and reduce airborne transmission rates, air purifiers equipped with HEPA filters can play an important role when used in homes and public environments such as waiting rooms. By using HEPA filters in both vacuums and air purifiers, users can reduce the amount of airborne allergens and pollutants in the home. The Department of Energy (DOE) specifies that the HEPA filters used by DOE contractors must be able to remove 99.7 percent of airborne particulates of 0.3 microns or more, but there are no federal or national regulations for the consumer industry. To maximize contaminant removal from the air, purchase a HEPA air purifier that contains additional filters such as a carbon filter and a prefilter.
