Air Purifier! - the "Window Fan" Air Filtration System! - Easy DIY (w/box Fan Conversion!)

in this instructable i'll show you how convert a window fan into an air filtering window fan

Homemade Air Filter! The "Window Fan" Air Filter! Easy DIY. Purifies large volume of outdoor air (for lots of clean/fresh indoor air). Made with a Flanders cut-to-fit "Natural Aire" low-resistance/high velocity air filter, a window fan and zip ties. air filter i used filters out dust/lint/dust mite debris/pollen and mold. cost $5. chose type of filter to suit your needs (smoke, smog, pollen, mold removal etc...). studies show these types of air filter/fan setups work as well (or better) than much more expensive commercially available units. lastly, the filter i used is rated to be 2x better than similar polyester filters and lasts up to a year (versus only 30 days for many)

1.) one (or more) window fans

2.) a cut-to-fit air filter (choose the type that best suits what you want to filter)

3.) zip ties

4.) only tool needed: scissors

first measure the fan. then cut the air filter to match. i used a 20" by 30" (cut-to-fit) air filter. the cut was roughly 10" by 20". (that left a 20 by 20 piece - which was perfect for another air filter project. i'll show that near the end)

i connected the filter at the corners with the zip ties. make sure that the zip ties are nowhere near the fan blades. you can see it lays nice and flat

place the fan in the window as you would normally do. as you can see in the above pictures, i have the side sliding windows, so put something to block the dirty air from entering above the fan. i used the leftover piece of air filter, but you could also use plywood, plexi-glas or even cardboard.

it fit perfectly

this is the piece that was left. it fits perfect on the back of a 20 inch box fan. it's a low resistance, high velocity air filter, so there is no "drag" on the fan. they work great on box fans too!