CleanAirKits - Corsi-Rosenthal Box

Google “Corsi-rosenthal box”. There is nothing more effective than this without spending thousands

Because of the added surface area of the 4x filters in a corsi rosenthal setup, filter changes occur much less frequently. You’re talking 5-6 months so your cost estimations are way off there.

Then let’s also factor in how they’re more effective, more repairable, less upfront cost, and will be eternally supported as you’ll always be able to buy furnace filters and a box fan. I do agree that over the long run they’re not more cost effective (assuming companies continue to make filters for their products) but they’re still the better option

Nah it’s not subjective. Tests have been performed and CR is truly the more effective option. You’re acting like applying duct tape involves an engineering degree. One of the aforementioned [tests](https://www.rtings.com/air-purifier/learn/air-purifier-performance)

My air purifier is a [diy one](https://en.wikipedia.org/wiki/Corsi%E2%80%93Rosenthal_Box) out of a box fan and merv 13 filters. So I'm just adding a smart plug to it. You could just get a dumb one with a smart plug? might be cheaper

An extremely effective option is a Corsi Rosenthal box, they're diy and dirt cheap, but kind of ugly. Just Google Corsi Rosenthal box and there are directions everywhere, or you can buy an assembly kit on Etsy for pretty cheap

Have you heard of Corsi-Rosenthal boxes? They are DIY (make it yourself) air purifiers, the basic model is a 20" box fan plus four furnace filters, with duct tape and cardboard to seal up the bottom and to cover up the corners of the fan. You can choose the level of filtration you want. Depending where you get your stuff you can maybe do it for under $100. Whichever you choose, pre-made purifier or CR box, make sure to note the cost of replacing filters and how often you will need to do so. From what I know, the 3M Filtrete furnace filters are best to use in CR boxes since they have the least airflow resistance. Whatever level of furnace filter you get, it's not going to be as good as HEPA (the top ones are close though) \*\*but\*\* CR boxes have a lot higher airflow than air purifiers, so the air can actually get more filtered since it goes through the filters more often. You can also add carbon (VOC/gases) filter layer to a CR box if you want, though they mostly are just particle filters because their popular use is to clean air of virus.

I have several air purifiers and my favourite is a PC fan air purifier from North Box. There are various ones on the market but [North Box is Canadian](https://aidankepo.wixsite.com/northboxsystems). It's available directly from their site or through [Donate A Mask](https://shop.evidencebased.ca/collections/cr-boxes-air-purification). What's nice about PC fan air purifiers is that they're really quiet, quite effective and don't rely on proprietary air filters.

As u/ZedZabeth mentioned, making a Corsi Rosenthal box is a good idea. If you can afford it, a PC fan air purifier uses very little energy, is quiet and takes up less space than a classic CR box. If money is really tight, a respirator mask is probably the easiest, most accessible and cheapest solution. I know the prospect of masking at home is unappealing, but even masking from time to time indoors will lower your exposure.

Corsi box is where it's at. Ours is with 2'x4' filters. Sits in the foyer with high 2nd story ceilings and open to formal living, dining, and kitchen (easily 2k+ sqft), been on 24-7 for 4 years.

We built a Corsi-Rosenthal box using materials from the still-open Home Depot. All you need is four 20x20x1 MER 13 filters (coincidentally 50% off when you buy four), and a 20" box fan. It's the single best air purifier you can get, and it's one of the cheapest and most accessible. Ran us about $40 at Home Depot last night, and it cleared up all the smoke in our apartment in no time. I recommend also sealing your doors and windows with duct tape, which you'll need anyways to build the filter. Instructions for assembly: https://corsirosenthalfoundation.org/instructions/

My wife built two of these for our house. She despises dust. They work pretty well.

One is in the front door foyer to blow up the stairs. The other is in the living room. We have a dog that sheds a lot and that's where he spends much of his day.