One effective way to improve indoor air quality during wildfire events is by using an air purifier. But buying a high-quality air purifier can be expensive.
In this article, we explore an affordable and practical solution: making your own air purifier using a fan, some filters, and a few other items from home or your local hardware store.
Follow these simple steps to build a system to clean the air in your home to protect your family’s health during smoky periods.
Step 1: Gather your materials
Before diving into construction, you’ll need to have your materials ready. All the items you will need should be available at your local hardware store:
- 20” x 20” box fan with a flat front or back (~$30.00 CAD / $24.99 USD)
- Four 20” x 20” air filters rated MERV 13* (~$100 CAD / $60.00 USD for 4)
- Duct tape
- Cutting tool (e.g. scissors or utility knife)
Step 2: Arrange the filters
Begin by arranging the filters together, forming an incomplete cube shape with two opposite ends left open.
Step 3: Check airflow direction
Pay attention to the airflow direction of each filter – you can usually find it on the top. The air intake direction of the filter should point inward, towards the centre of the cube. This is essential for proper air circulation and filtration. Rearrange your filters until they all point inward.
Step 4: Duct tape the filters together
Carefully tape each side, making sure not to tape over the filter material itself. Once the filters are duct taped together, you’ll have two empty sides of the incomplete cube. One side will hold the box fan, and the other will hold the cardboard base.
Step 5: Tape cardboard to the base
Cut a piece of cardboard to fit over the bottom area of the cube where it will sit against the ground. Duct tape the cardboard securely to the bottom of the cube, again making sure not to tape over the filter itself.
Step 6: Attach the fan on top
Duct tape the box fan to the top of the cube. Make sure that the fan is oriented to blow air out of the cube, rather than into it. You’ll get the best results if the fan is pointed directly upward. Now you’re ready to turn it on!
Tests show that a homemade air purifier like this can be equally effective in improving air quality as ones you can buy – with a Clean Air Delivery Rate (CADR) of 306-443. Bear in mind it won’t have the additional features and will be noisier than the ones you can buy.
However, at between ½-⅓ of the cost of some store bought options, this DIY purifier might be a good fit to help keep you and your family safe during wildfire season and beyond.
*A note on MERV
MERV stands for Minimum Efficiency Reporting Values and indicates a filter’s capacity to trap certain pollutants. To capture very small pollutants like wildfire smoke indoors, the U.S. Environmental Protection Agency suggests using a filter with a MERV 13 rating and above.