The HEPA filter is the core of any purifier so we chose one that was backed by data rather than by grade. Grades are based on the ability to trap size 0.3 and above - all HEPAs will trap virtually 100% of nanoparticles (down to 0.005).

The tighter the HEPA fibre, the more resistance to airflow and without a powerful fan, it really doesn't matter which HEPA grade you choose.

If your goal is the fastest clean air, then look at the HEPA grade. If the goal is the most clean air overall, then use our calculator to work out how many air changes you will get per hour for your room size.

* The Smart Air filters are certified to GB13554-2008 (now updated to GB13554-2020) & GBT6165-2008 standards. This is the Chinese equivalent of EN1822 / ISO29463 and is an independent lab test

Our filters are sent via Royal Mail - 3 to 5 working days, except when ordered with a purifier (see purifier for courier details). All orders arriving before 11am (Mon-Fri) will be shipped out on the same day.

How long does The Sqair’s HEPA filter last?
Our HEPA E11 filters have been tested to last 1400 hours but this test was carried out in Beijing on the highest setting so if you live in a less polluted area and run your purifier on a lower setting, the filter will last you much longer.

How is the new HEPA E12 filter able to achieve the same CADR as the original HEPA E11 filter?

After much hard work by our factory and R&D team, we're happy to announce that we've been able to switch from a HEPA E11 in the Sqair to HEPA E12 filter without any change in CADR! Usually increasing the HEPA grade will lower the CADR but we revisited the materials with the factory and found an E12 material with slightly lower air resistance. After working on 10+ prototypes and tweaking the number of folds to the filter, we were able to provide a higher-grade filter with the same CADR.

What’s the difference between the E11, E12 and H13 filters?

Filters are graded on their ability to trap particle PM0.3 as this is the smallest particle size that travels in a straight line, not the smallest size that can be trapped. In fact, smaller particles travel in a zig zag way (called the Brownian motion) making it next to impossible to pass through the HEPA fibres. This means that most filters will trap virtually 100% of smaller / nano-particles (including the virus). If a company is saying their purifiers can trap particles smaller than PM0.3 they either haven’t done their research or, worse still, they are using this as marketing tactics to push sales.

In terms of the different options for the Sqair, the different grades will capture the following percentages of PM0.3:

HEPA E11 – 95%

HEPA E12 – 99.5%

HEPA H13 – 99.97%

Can I purchase the standard HEPA version and add a carbon filter at a later date if I need to?
Yes, no problem. The Sqair has been designed to work on just the HEPA filter, the Carbon Filter or both so completely interchangeable depending on your needs. The more filters you use, the more resistance in the airflow plus you will need to factor in the filter replacements. This is why we leave you to choose what you need, when you need it.

Can the filters be washed?
Smart Air Filters conducted tests using 4 used HEPA filters and found that washing the filters reduces its effectiveness. According to the data, we should never wash our HEPA filters. You can check out the data here: https://smartairfilters.com/en/blog/wash-clean-hepa/.

Is the HEPA filter made from fibreglass?
Data shows that glass fibre filters can shed more fibres than synthetic filters, while the number of particles shed by both types of filter is very small, Smart Air chooses to use synthetic fibres to lower the risk. Smart Air uses PP+PET material in all our HEPA filters.

Can the HEPA filter be recycled?
We really wish it could be recycled but at the moment it is not possible. If you have any creative ideas or suggestions on how we can do so, let us know!