There is no such thing as a truly/completely washable HEPA filter. In my review of the top HEPA filters article I explained that the reason HEPA filters are not washable is that they are removing extremely fine particles from the air. In fact, they need to be tested to remove at least 99.97% of all particles as small as .3 microns. (Chart below for your reference)
Most HEPA filters have a series of filters, not just one single HEPA filter. The first filter may be advertised as washable and reusable, but if you look closely the “True HEPA” filter is not in fact washable and needs to be replaced consistently in order to function properly.
|MERV Rating||3.0 - 10.0 Microns||1.0 - 3.0 Microns||0.3 - 1.0 Microns||.3 Microns||Is It HEPA?|
|1-4||less than 20%||-||-||-||No|
|6||20% - 49.9%||-||-||-||No|
|8||50% - 84.9%||-||-||-||No|
|10||85% +||50% - 64.9%||-||-||No|
|12||90% +||80% - 89.9%||-||-||No|
|14||-||90% +||75% - 84%||-||No|
If you are in the market for a HEPA filter and you have more questions than answers, please take a look at the blog post where I go through and exhaustive list if criteria and what to look for in a HEPA filter and review my top filters that you should look at before you make your purchase.