An inline duct fan would probably perform even better (see the discussion) but at a higher cost. Inline duct booster fans are fairly weak fans often used to help with grow rooms or range hoods. Four HEPA air filters, each approximately 32 cm x 22 cm and 5cm thick ($70 for all).An 8inch (20.32cm) diameter inline duct booster fan ($30).(Contact me if you want the exact products I used.) Materials used If each filter can remove a fixed amount of particulates before it needs to be replaced, then doubling the number of filters means also doubling the replacement interval. However, that extra cost disappears over time. Using more filters has a higher upfront cost - filters aren’t free. If we want to be quiet and energy-efficient, the choice is clear: Use a relatively weak fan, but with a large filter surface area. This will decrease the pressure on each of them, meaning more total airflow. Big filter: Keep the same fan, but install more filters in parallel.

Big fan: Keep the same amount of filter, but run a bigger/faster motor to push air through it faster.If you use a weak fan, it will barely push any air at all.įundamentally, if you want to increase purification, you have two options: If you’ve ever built a box-fan-based air purifier, you noticed that once you attach HEPA filters, throughput decreases dramatically. The fan/filter tradeoffĪir purifiers push air through filters. Somewhat accidentally, it’s also better at removing particles. Particularly on low, the cuboid is very quiet and energy-efficient. Electricity costs assume operation 24 hours/day at 1 kWh = $0.13.Īs you can see, the cuboid gives major improvements in noise and electricity consumption, with small regressions in cost, difficulty of construction, and IED resemblance. The half-life is calculated in a 31 m³ room. Less is better for everything except the clean air delivery rate (CADR). I’ve done some experiments comparing this to a box-fan based purifier, using the same filters.

The design should also fix the worst parts of using a box fan: I wanted a new design that preserves the best aspects of using a box-fan: Still, box-fan purifiers have two downsides: They create a lot of noise, and they consume a fair amount of electricity. They are cheap, trivial to build, and people around the world have done experiments to show they actually work.

Step 4: Set the fan on the filter column.

Step 1: Form a column out of the filters.

Cuboid net