Green Colour (Formaldehyde/Enhanced Version)

The ‘specialty’ of this filter is that its designed to target Formaldehyde. According to the CDC， ‘Formaldehyde is a common chemical that can be emitted from a number of products in the home. Smoking, pressed wood, and particle board have all been shown to be sources of formaldehyde. Higher formaldehyde levels are usually found in newer homes or homes with new construction.’

On the Xiaomi website, this filter is advertised as a H11-grade HEPA filter that filters up to 99.3% of 0.3 microns. If we go by the EN1822 standard, you will see that this filter doesn’t meet the HEPA standard today. This is because the updated EN1822 standard has now categorized H11 as E11 making this filter EPA and not HEPA. Granted， this filter was released a while back in 2015 so the HEPA definition would have stood still then.

This filter has an antibacterial layer can trap and kill dust mites. It’s able to trap 0.3 micron particles but it doesn’t mention whether its a EPA or HEPA filter.

Which should I get

The choice is simple; it’s either a HEPA filter or a non-HEPA filter.

Non-HEPA

If you aren’t fussy about filter grading, then you have 2 options; the Economic Version (Blue Colour) and the Antibacterial Version (Purple Colour). Get the Economic Version if you want a standard filter and Antibacterial Version if you want something that targets bacteria and dust mites. Both come with an activated carbon layer.

HEPA

If you want a HEPA filter, then the Formaldehyde/Enhanced Version (Green Colour) type is your choice. This filter also comes with an activated carbon layer. If you can get a HEPA filter, do get one. This is because a HEPA filter ranks the top when it comes to filtering minute particles.