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Free Tool to Measure the Air Changes Per Hour of Your Space

Use this free tool to determine the Air Changes Per Hour (ACH) of a room based on its dimensions and whether or not the air purifier you’re considering will clean the air properly.

Air Changes Per Hour Tool


According to researchers, poor ventilation plays a role in transmission of Covid-19, not to mention other serious respiratory illnesses. That’s why it’s so important to make sure you have clean indoor air. How?

A term you’ll see used is “ACH”, or air changes per hour. ACH is a measure of the air volume added to or removed from a space in one hour, divided by the volume of that space. The higher the ACH, the better chance you’re breathing good, clean air.

How can you ensure clean air indoors?
  1. INTRODUCE CLEAN AIR FROM THE OUTSIDE. This means opening doors or windows, or pulling clean outdoor air into a space via a fan or duct*.
    *If the air outside isn’t clean — think “places with pollution” — make sure there’s a filter in front of that fan or inside your duct to capture pollutants before they’re breathed in.
  2. CHOOSING FILTERS FOR YOUR HVAC SYSTEM THAT REMOVE VIRAL PARTICLES. MERV 13a or higher, HEPA or silver-ion treated filters should be considered & evaluated for effectiveness in your particular HVAC system.
  3. USING PORTABLE AIR PURIFIERS WITH HEPA FILTERS AND/OR UV-C LIGHTS. Make sure they’re sized to give you the right amount of clean air. Our tool can help.