March, 20
by RT

The Go-To Guide for HEPA in Grow Rooms

When it comes to HEPA air filters and air scrubbers in grow rooms there seems to be a lot of questions and speculation. For those who are serious about growing, utilizing best practices is a no-brainer, but it's still important to understand why and how methods work. In an effort to provide growers with accurate information about HEPA filters, I've created this guide to clear up answers to some of the most commonly asked questions.

The Go-To Guide for HEPA in Grow Rooms

What type of HEPA filter is best for a grow room?

TRUE HEPA filters provide the highest standard of clean for indoor grow rooms.

Will HEPA filters remove mold spores?

No. If plants are infected before implementing a HEPA filter it will not remove mold. HEPA filters prevent mold and should be established before starting the growing process.

Will a HEPA filter remove smells?

In short, yes but not efficiently. If odors are your main concern you're going to want a carbon filter. HEPA filters focus on overall air quality vs. odor control.

Can HEPA filters be washed and reused?

There are HEPA models that claim to be washable and there is even a wikiHow on how to clean HEPA filters however, there a few important things to note:

  • If you wash HEPA/ TRUE HEPA filters they will fall apart
  • There is no confirmation that these washable filters work after being cleaned
  • Removing AND cleaning a HEPA filter in or near a growing area is a terrible idea

Which HEPA filter is best?

If you are looking for a true medical-grade clean room environment, TRUE HEPA filters are best.


  • HEPA filters capture 99% of particulate that is 2 microns or larger (think pet dander and dust)
  • TRUE HEPA filters capture 99.97% of particulate down to 0.3 microns (anything under 50-60 microns is invisible to the human eye)

When should HEPA filters be changed?

  • In normal grow room environments, TRUE HEPA filters can last up to 4 years.
  • In commercial environments, HEPA filters should be checked every 6 months and changed once a year.


The MERV rating ranges between 1 and 16 and is based on how small of particles a filter can collect. The higher the MERV rating the better the quality of the filter.

Low MERV: 1-4

Medium MERV: 5-13

High-Efficiency MERV: 13-16 (filters can collect particles as small as 0.3 microns @ a 75% efficiency rating)

HEPA air filters range from 17-20 MERV which is why they are used in hospitals and other surgical-grade clean environments.




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