How to Make a DIY Air Filter | Ask This Old House

Summary by Krater

The hosts explain MERV ratings for air filters and demonstrate how to build a DIY cube air filter using four 20x20-2 filters and a box fan, achieving high airflow and filtration at a low cost.

From the video

Answers: How do I make a DIY air filter using a box fan?

• MERV air filter ratings
• DIY air purifier cube
• Air filtration and particle size
• Box fan air filter build

What it concludes

• MERV 1 filters are only good for catching large particles like pet hair and dust, while MERV 13 filters catch very small particulates like smoke and viruses.
• Using a 4-inch filter instead of a 2-inch filter doubles the surface area, halving the air resistance and pressure drop.
• The Comperato Cube uses four MERV 13 filters attached to a box fan to increase surface area, decrease pressure drop, and move more airflow for under 100 dollars.
• The DIY cube air filter needs filter replacement approximately every 6 months depending on usage and surface loading.