Dust in the air is a problem in the city, apart from that there’s NOx, Ozone, partially burned fuels that all have negative impact on long term health. To make sure the air in house is clean one can buy a commercial air conditioner, but we figured we’d try to build one ourselves. The total cost of this build could be 100,- Euro or less.
Air quality for residential areas is not checked often, yet there’s ample reason to be interested. Next to bussy roads the air is full of toxic and corrosive gasses. Also sewage systems can vent H2S which is also corrosive. Restaurants and heating installations also produce gasses we might want to remove from the air we breath.
Smog can be invisible too..
There are standards for air quality. We’d ideally want to know exactly what quality we reach just to see if it is any use to filter at all. Clean rooms, operation theaters have normalized air quality, delivered by industrial filter machines (so no germs, no dust to mess up semiconductor fabrication). Fine particle dust, the most dangerous type, is hard to filter except with electrostatic filters. A dutch invention combines electrostatic and mist to bind particles to water and then move water out of the airstream to clean out the dangerous dust, but such machines are expensive and consume a lot of power.
We build a combination of active carbon and HEPA air filter. HEPA filters are recommended for fine dust removal. The active carbon filter is a standard unit we bought from a ‘grow shop’, who can have a surprisingly wide offering of scent removing equipment ;-). We buld a box with ventilators to house the filters. Air flow volume seems acceptable but we can’t measure it. We got in touch with a true air filter manufacturer and they will alert us when they have a real unit. Parts for this unit you can order through email@example.com on a per case basis.
Ventilators are in the top so the air and dust flow downwards into the HEPA filter…
We make a round opening in a plank that will carry the activated carbon filter that’s in a neat metal container. It already has a rough dust filter on the outside. Any carbon falling out will be stopped by the HEPA filter below. Make sure to mark the side on the filter that is the input side, or you will be blowing out dust when you remove it.
The end product can already be seen in the picture above. It can be made less noisy if the ventilator was placed after the carbon filter, inside the box. We would try to create a loose connection with the box so the noise of the ventilator would not resonate in the box..
Air filter tower, 45 x 25 cm
We used a sheet of 122 cm x 60 cm x 0.5 cm wood, the HEPA filter is 25 x 25 cm, so we cut two planks of 25 x 25, four sides (2 of 25 x 45 and 2 of 26 x 45 cm) and fitted it all together with blocks of wood. To replace the HEPA filter we need to unscrew the support rods below it. To replace the carbon filter we take the top off. If you order 10 kits at the same time we can thin of a price, ask us at firstname.lastname@example.org 😉
Update : This design is reconfigurable, because the carbon filter holder and the ventilator holder are the same size, so you can swap them and end up with the carbon filter on top of the box. Having the ventilator inside gives the opportunity to add some sound proofing. With different side panels you could add some tubes so you can put the thing where the noise doesn’t bother anybody..
Total cost of this build is about 100,- Euro. We will ship it as a kit for 150,- with precut wood and drawings, probably with a 220 Volt AC ventilator with a little more oomp..