Step by step

Maximize ventilation at your business during the pandemic

Your business must set up as much airflow as possible to be open to the public. See your options.

All businesses must get air moving when people are inside, to reduce the risk of COVID-19 transmission. Choose a method depending on what you can do at your business. 

If you have indoor areas open to the public, you must post a checklist for visitors to see.

See more ventilation guidance from the Department of Public Health. Email your ventilation questions to


Check your HVAC system

Work with building engineering or maintenance staff before you work on a mechanical ventilation system.

Switch modes so that fans are always on. Disable on-demand temperature controls. Consider running your fans for 2 hours before your business opens, and after it closes to the public.

Open outside air dampers to maximum, if you can. Minimize recirculated air.

Switch to the highest-rated filter for your system. Aim for MERV 13 or higher. Regularly check and replace your air filters.

Make sure the room meets building code.

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Get a portable air cleaner for each room

Make sure your air cleaner is certified for ozone and electrical safety. Get an air cleaner that can purify air for the room size you’re using. 

You can also build your own air cleaner. Tape a 20” by 20” MERV-13 air filter to the intake side of a 20-inch box fan, where air goes in. Make sure to only use the fan when there is someone in the room to watch it. It may overheat.

Place air cleaners in the middle of the room where people will be.

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Keep all your doors and windows open

You do not have to keep doors and windows open if there will be a safety hazard, such as falling. Fire doors should be kept closed.

If you have ceiling fans, adjust them so air is pulled up towards the ceiling.

If you cannot keep doors and windows open, you must move your services outside, or to another room where you can do that.

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Last updated January 12, 2021