HVAC Systems and Do-It-Yourself + Portable Air Cleaners

Do-It-Yourself (DIY) Air Cleaners

DIY air cleaners are an affordable and accessible way to protect yourself from air pollutants. DIY air cleaners are made with a box fan and a MERV 13 or higher air filter. MERV 13-16 air filters can filter more than 95% of particles from the air. The U.S. Environmental Protection Agency (EPA) offers several diagrams for building DIY air cleaners, pictured below.

Both the Basic and Augmented DIY Air Cleaners will improve indoor air quality. Using thicker filters, using multiple filters, and adding the cardboard shroud can improve any design you choose to create. Be sure to keep extra filters on hand and to replace air filters regularly (after 3 months of use or when the filters appear dirty).

Portable Air Cleaners/Purifiers

To protect yourself from indoor air pollution, you can also purchase portable air cleaners or purifiers, which are intended for small spaces and single room use. When choosing a portable air cleaner, you must calculate the square footage of the room where you plan to use the air cleaner most often and then choose an air cleaner with the appropriate Clean Air Delivery Rate (CADR). The U.S. EPA provides a sizing chart for the selection of a portable air cleaner, which is provided below.

During a wildfire smoke event, it is recommended to use the highest fan setting on the portable air cleaner. The minimum CADR is calculated based on the highest fan setting, and so running your air purifier on this setting will ensure you are most effectively filtering the air.  Please note that many portable air cleaners can be loud, especially on highest fan settings. If this is a concern, you can select an air cleaner rated for a larger room and use it in smaller rooms at lower fan settings.

To maintain your portable air cleaner, you should:

1. Change the air filter regularly. Your air cleaner will likely come with a user manual with cleaning recommendations, but you may need to change filters more frequently during wildfire smoke events.
2. Clean the outside of the air cleaner. This will ensure your air cleaner is not building up harmful particles that can be blown back into the air.
3. Provide your air cleaner with enough space. Putting an air cleaner in the corner of a room can restrict air flow, making the air cleaner less efficient. 

Heating, Ventilation, and Air Conditioning (HVAC) Systems

Heating, ventilation and air conditioning (HVAC) systems are also an efficient way to improve indoor air quality throughout a house or building during wildfire smoke events. Upgrading and maintaining filters in HVAC units will ensure your unit is working efficiently and properly. 

• When choosing filters for your HVAC unit, it is recommended to consult with an HVAC specialist. Every building and HVAC system is different, and this may affect air filtration capabilities. Most HVAC units can accommodate the recommended MERV 13 filter. Make sure that the filter that you use fits tightly into the HVAC unit so that no air can bypass the filter. 
• If you are unable to use a more efficient filter, indoor air pollution can be reduced by running the system continuously. 

Before a wildfire smoke event, ensure that your HVAC system is functioning properly and that you have extra air filters on hand. During heavy use of the HVAC unit, you should check the filter for dust and debris at least once a month. Filters should be checked and replaced more frequently during wildfire smoke events.