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Ceiling Air Purifier

jefftk.com

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Re: Ceiling Air Purifier

#3
post #2

Isn’t the dust just going to rain down on you as soon as you turn the fan off?

Mostly no: it's tiny particles that get embedded in the filter.

One way to see this empirically is that pm2.5 levels don't go up again after turning off the fan

Re: Ceiling Air Purifier

#5
If you have a whole-home furnace you can often make it run the fan even if cool/heat is off - and install a high power filter and change it regularly and it’ll filter the air reasonably well.

The ecobee has a “minimum fan time per hour” setting - it can also help to balance the air temperature.

Re: Ceiling Air Purifier

#6
Great idea. What's worked for me is simply taking a 20"x20"x1" filter and sliding it into the back cover of a standard $25 Lasko box fan. Cheap, easy option for air filtration in the home.

Re: Ceiling Air Purifier

#7
Very cool, if I was going to build something like this de novo I would start with a squirrel cage fan. When you oversize them and run them at low RPM they can produce a startling amount of airflow with virtually no sound at all. You could also bump it up to a MERV 16 with enough intake filter area.

Re: Ceiling Air Purifier

#9
There doesn't seem to be good control tests to say what difference the filters really make - seems one was added in in the comments, but it's missing important details (is the control with everything off? What happens if the fan is running on medium or high, etc.?

And, of course, it's not really practical in that most people really don't want to be sticking stuff on their ceiling, but it could be an interesting experiment with more details provided.

Re: Ceiling Air Purifier

#10
post #5

If you have a whole-home furnace you can often make it run the fan even if cool/heat is off - and install a high power filter and change it regularly and it’ll filter the air reasonably well. The ecobee has a “minimum fan time per hour” setting - it can also help to balance the air temperature.

I've had HVAC techs tell me not to use those thick filters unless your system is designed for it. They make the fan work harder to pull less air. This reduces how much air it can move.
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