Homemade Air Purifier & Cat Litter Box Air Filter





Introduction: Homemade Air Purifier & Cat Litter Box Air Filter

My cats' litter box makes a lot of dust.  One way to capture the dust is with a store-bought air purifier.  Ever price one of those department store air purifiers?  Some of them run upwards of $100.  And the filters?  Well, if you think replacement razor blades are expensive, you don't want to know about replacement filters.

So I made my own air purifier out of a cheap fan and a cheap furnace filter.  Here's how...

Step 1: What You Need

* Squirrel-Cage Fan - $22
** Air Filter - $8
Wire Cutters
Duct tape

* Standard rotary fans don't work as well.  Plus, it's harder to cut a circular piece of filter.

** You pick how much filtering power you want by choosing the quality of the air filter.  You can get different MERV ratings.  Spun glass filters don't work; forget those.  Pick a filter height that matches the height of the air flow openings in your fan.

Step 2: Open Up Furnace Filter, Cut to Size.

This is the hardest step, which isn't very hard.  Carefully open up the cardboard frame of the filter.  It's glued in a number of places and is not meant to be opened, so take your time and don't mangle the filter element.

Keep the wire mesh frame; it's too hard to remove.

Stretch-out the pleated filter so it is flat.  I used the edge of a table to straighten each pleat.

Cut a piece that completely covers the back air flow opening on the fan.  Use old scissors - they will cut through the wire mesh but will damage them slightly.  Using wire cutters on the mesh only for a first-pass will work too.  Then use scissors to cut the filter itself.

Step 3: Duct Tape Filter in Place

All that's left to do is duct tape the filter in place over the back of the fan.  Be sure to overlap the air flow openings so that there are no holes through which the air flow can bypass the filter.

Step 4:

That's it!  I use mine to filter cat litter box dust.  A store-bought air filter would get plugged up in a couple weeks.  If a store-bought filter is $25, I can get 4 filters from one furnace filter that costs $8.  That's >12x savings on the filters!

And no custom filters to go obsolete on you!

The squirrel cage fan is quiet on low speed, so it doesn't flip out the cats.

Hope you (and your cats) like it.

(OK, the cats couldn't care less...)



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    14 Discussions

    Does this also help filter out the litter smells? I've seen some air purifiers that say will rid the room of any nasty smells and was wondering if this will do the same thing. Dryer sheet sounds like a good idea too!

    5 replies

    Amazon has activated charcoal furnace filters, and cut-to-fit carbon pads for purifiers. Those would probably help.

    Probably not. Dryer sheets will cover up the smell. You could try Febreeze. The recipe for no-odor litter box is: throw away all the litter periodically and wash the pan with soap and water (no harsh chemicals). Baking soda is a miracle chemical -- and cheap. Sprinkle a cup into litter and/or place an open container nearby.

    i ended up getting two air purifiers and one alone doesnt get rid of the smell. its more of a dusty stale smell not really used litter or poo smell. I ended buying another kind of litter and will replace the old stuff and see what happens.

    Not really. Best to scoop asap and clean box with soap & water 1x/month.

    I also add baking soda -- the wonder chemical. Absorbs smell amazingly.

    I remove the dust before putting it in the litter box. Start with a clean, dry shop vac. Remove the filter from a shop vac, and vacuum the entire container of new clean litter into the shop vac. The litter stays in the vac and all of the dust is blown out the exhaust. (Do this outside) . Pour the must less dusty litter back in the original container. I remove the filter to increase air-flow and dust separation and because the fine dust would clog the filter quickly.

    3 replies

    Whoa. Great idea. This effectively removes the very fine litter particles?

    Yes it works well. I can dust 30 lbs of litter in about 10 minutes. Two passes removes more. I had an idea to use a 5G bucket as a separator and built it this weekend for about $15 - it worked even better and I could leave the litter in the bucket when i was done. - didn't have to clean the vac first or remove the filter. If you look on amazon for "dust collection separator" you'll find 5G bucket lids that are basically the same thing.

    The dust is fine and very dry and will turn to a thick sticky mud if you get it wet. It can clog a vacuum filter. You can remove the filter and blow the dust into the air if you're outside, or blow it off with a compressor when your done.

    One funny thing about running litter though the vac - it can creates a large static charge on the plastic hose. It will tingle and pop you through the soles of shoes. So you may want to wear a glove or stand on a couple inches of cardboard while you do it.

    gonna try this for dust removal
    may just try using sand for litter
    hate that DUST !!

    1 reply

    My filter gets full fast. Can extend life somewhat by vacuuming outside of filter, but need to change filter more than I do.

    This is a pretty nice Idea. I have only one suggestion, why not add a couple laundry sheets in the outside of the filter where the air exits to give off a fresh scent to work in harmony with the filtering.

    1 reply

    You mean those fabric softener/dryer sheets? Sure. Do this for you though; the cats don't care...