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Vacuum Cleaner Filters Explained What is HEPA Filtration?
HEPA (High Efficiency Particulate Air) is a filtering efficiency specification for highly sophisticated filters developed during World War II to remove radioactive dust from nuclear power plant exhausts. HEPA filters must retain all particles as small as 0.3 micrometer (formerly microns with an efficiency rating of 99.97%. A 0.3 micrometer filter will capture soot, pollen, black and color copier toner and the majority of atmospheric dust particles.
HEPA filters are a pleated or 'extended surface' filter made of glass microfibers. The HEPA acronym is used primarily in the United States, while Europeans often refer to the same filter as an S-Class filter. Certified HEPA filters in both the U.S. and Europe are marked with a certification number.
What is a sealed HEPA system?
A sealed HEPA system is not only a HEPA filter but an entire system that meets HEPA standards. This is accomplished by not allowing the air passing through the system to escape around the filter. If you have a HEPA filter but air is allowed to escape without passing through it, the filter is not accomplishing its purpose.
Is HEPA always HEPA?
Some manufacturers have developed their own terms. For example, several manufacturers use a 'HEPA type' filter which does not meet the stringent standards set for a true HEPA filter. The key to proper comparison is the size and percentage of particles captured. Almost any systems could be rated at 100% filtration if the dirt particles were large enough.
How effective are multi-layer filters?
||Experiments were conducted on the filtration performance of multi-layered media, such as the white-yellow-green filters used by some vacuum cleaner manufacturers. The experiments showed that multiple layers do not perform as well as calculated from filtration data on the individual layers. The layers must be separated for best results.
What are important filter characteristics?
Filter efficiency is determined by the type, size and number of particles the filter is able to trap. Overall filter performance depends on a number of factors:
How many filters does a vacuum cleaner have?
- Is it pleated? A pleated filter provides additional surface area on which particles can be trapped
- Is it electrostatically charged? Filters with electrostatic charging can attract and capture particles that other filters can miss
- What type of particulates does it capture?
- What is the filter substate's efficiency?
Not counting the bag, which is part of the overall filtration process on bagged vacuum cleaners (see Dustbags Explained), many vacuum cleaners possess two or more filters. They are:
How often should I change the filters on my vacuum?
- Pre-filter (also known as pre-motor filter, motor filter or after bag filter) - filters air before it enters the suction motor
- Exhaust filter (also known as final filter, output filter or after filter) - filters air returning to the room
In general, plan to change foam, cloth or paper pre-filters and exhaust filters every three months. Change them more often if your home is large or has new carpet, if you have children, if there is a lot of foot traffic in your house or if you have pets.
HEPA filters need to be changed (or cleaned, if washable) every six to twelve months. If you cannot see light through the filter when holding it near a light source, change it immediately.
Filters are either disposable, washable or vacuumable. You should follow the manufacturers' guidelines on how often to change, wash or vacuum the filter in your particular vacuum cleaner. Note that cleaning a washable filter requires you to handle the dirty filter - exposing you to dirt and any captured allergens. A disposable filter results in much less exposure since you just place it in the trash.
What happens if I do not change the filters?
Vacuum cleaners will lose suction power and eventually stop picking up dirt when the filters are dirty. Some poorly designed motor filters let air bypass the filter when they are dirty. This can damage the vacuum cleaner's suction motor and result in an expensive repair.
In addition, a clogged output filter (alternatively known as exhaust filter or after filter or final filter) increases strain on the suction motor. This can result in poor suction performance and reduced motor lifespan.