Shop air circulation question

[jtooley75]

So I will be installing a window AC unit in my garage wall for AC during the hot Texas summers so I can work with the garage door closed. Do you think I should have an additional air circulation option like a window fan or air filter inside? I am installing dust collection but didn't know what would be better for not only dust but chemical fumes from finishing. Any suggestions are appreciated.

[fransikaner]

I am not an air quality specialist, but here are a few considerations.....

There is a fine balance between vertical air movement through temperature gradation and artificial air circulation that uses both horizontal and vertical vectors when you are looking at air quality.

Very few DC setups achieve 100% effectiveness, so you will end up with residual dust in the air, no matter how hard you try. The trick is how do you deal with that free-floating dust.

Another consideration is space volume. If you are like most, you have an 8-9' ceiling in your garage. Frankly, anything under 12' or so implies you have limited volume to achieve particle dispersion or significant vertical temp gradients.

I mention this stuff only because it means that you will have to rely on mechanical means to achieve the air quality objectives you seek.

Conventional wisdom suggests that you do not want additional mechanical activities affecting the performance of your DC system. Anecdotally, ceiling air filters and fans of various sorts stir up more dust than not.

As for mitigating chemical fumes, any products that are not water-based should not be used indoors without proper commercial-style ventilation- and that is an entirely different discussion.

You are going to have a hard time getting the win-win here. The DC is going to exchange anywhere from 650cfm upwards to beyond 2000cfm. That means a lot of air movement on its own. If you are not replacing that air with outside air (which means bringing in a lot of hot air into your shop), then you must rely on the effectiveness of your DC filters and suction from the source for your main air quality.

Your temperature management can best be achieved by heavily insulating your ceiling, looking at some wall insulation, gap management around doors, etc, and installing the AC as high as you can. I would suggest looking at options for enhanced inline filtering of your AC since it will be sucking in that free range dust.

As for fume management, the only viable home shop solution is to use a downstream filter/fan in a portable spray booth for water-based products. Again, I caution you about using hazardous materials indoors. Unless you are using an oxygen breathing apparatus, no face filter is going to provide you the protection you need.

This probably hurts more than it helps. For further, more authoritative reading, google:

Bill Pentz

Wynn filters

Phil Thien