How to Make a DIY Air Purifier

I'm Tim Heffernan .

I'm a senior writer here and you might say that I am a fan of air purifiers today , we're going to talk about actually making an air purifier of your own using a box fan and a furnace filter .

Like you can see here , air purifiers are a great way to clean the air in your home to remove particles like mold , pollen , smoke dust and even things as small as viruses and bacteria , they can be a little bit expensive .

And if you're not quite ready to take the plunge , there's a way to make them using really inexpensive materials .

You can do this with stuff that you may already actually have lying around your home assembly is pretty straightforward .

First thing you need is the filter itself .

You can see that this one is 20 inches by 20 inches .

You'll also need , of course , a box fan .

Again , a square one is ideal because it's easier to fit a rectangular or square filter to it .

The fan that we got is also 20 by 20 square , which is a common size .

The last thing you need is some tape .

We think that clear packing tape is probably the easiest I find it easier to begin by putting tape onto one side of the filter itself and then putting it up against the frame of the fan and pressing the tape down .

Once you've done that , continue all the way around taping each of the sides .

The only thing you really need to worry about is that the tape is fully sealed to the frame of the fan .

If there are any gaps , air can get around them rather than going through the filter and what you don't want , but you don't have to get it perfect .

The first time once you've got it roughly taped on , go back over .

And if you find any gaps fill them in with some more tape , a note on the filters , you want one basically that looks like this , that looks like it's made of white felt .

The one you want to avoid is the more basic , those typically are made of blue or green like nylon string .

Basically , it looks like a loosely woven net for any of the finer stuff .

They essentially do nothing again , look for one that's white like this .

They're typically going to have some kind of a rating on them where you want maybe a Merv 10 to 12 .

If you can see it , if the manufacturers use their own ratings go for something that's sort of on their higher end .

You know , it may seem crazy that such simple and inexpensive materials can replicate or at least approach the effectiveness of air purifiers .

But in fact , it makes a lot of sense .

He air purifiers , that's the most common type .

And the type we recommend really aren't much more than a fan and an air filter .

They're specifically engineered to move the air efficiently and filter it very efficiently .

But fundamentally , that's what they are and fundamentally that's what this is too .

How well do they actually perform ?

We ran tests on this .

We ran the same tests that we do for all of our dedicated air purifiers , which is to say I burned a bunch of matches in a room and then filtered it for half an hour .

This thing when we ran a test removed about 87% of those smoke particles , which is pretty good for a comparison .

Our top pick routinely got 98.9% 99% removal over that same period , but 87% is really not bad , but also form the $800 molecule air purifier even when we ran the molecule on its highest setting .

So it's kind of interesting that for 50 bucks , you can get better performance than a machine that will cost you almost 1000 bucks over the course of a year .

We do want to make clear that this really shouldn't be seen as like a permanent long term solution .

It can be effective like in an emergency if a wildfire has come through or if you've , you know , burnt Thanksgiving dinner and your house is full of smoke , something like this can actually fairly rapidly improve the quality of your air .

We just don't think that this is a long term permanent solution can't vouch for the fan lasting because this is a non traditional use for it .

And although it works fairly well , it doesn't work nearly as well as an actual dedicated puri flyer .

But again , in a pinch , it's a lot better than nothing for more context .

Or if you just want to move a little bit beyond this simple diy rig that we're talking about here .

See our guide to air purifiers at wire cutter .

Well , I'm such a smuggler on this one .

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