# Air Filter

 Review by David Murray posted 02-14-2010 06:23 PM 6698 views 1 time favorited 7 comments

I finally took the plunge and bought an air filter unit for my shop. It was a purchase that I didn’t put on a very high priority. My thinking was “It really isn’t really a tool”, after all you can’t cut, shape, grind, drill or sand with it. After all I have a dust collector what more do I need. I always figured the fine dust that was always collecting on everything was okay, after this is a woodworking shop. Then I read a few articles on the long term health hazards of fine dust to the lungs, so I thought maybe its time to make the investment.

After doing research on several different units I went with this Grizzly model for several reasons. Due to the size of my shop(30’x35’) I wanted a fairly high CFM. After using this formula to figure out how many times it would recirculate the air in my shop per hour.

Step 1. Calculate, how long it takes to circulate all
the volume of air in a room with the double air filter;
where W = Width, L = Length and H = Height
of your room, in feet. The rate of air movement for
the air filter is 1400 cubic feet per minute.

W’ x L’ x H’ then divide that number by CFM rating. for my shop it worked out to 7.5 mins.

Step 2. Calculate how many times per hour the
volume is recirculated through the double air filter
by dividing 60 minutes by the amount of time it
takes to circulate the volume once. The result is
listed as times per hour.

For my shop it was 7.5 times per hour. Compares to 5.7 times per hour for a 1000 CFM unit.

I hope I didn’t confuse anyone other than myself. Now to the unit I bought.

It has 2 filters a primary one that is a standard 16” x 20” filter (a furnace filter would work), the one that came with the unit is 30 micron and washable, it has a carboard frame so I’m not sure how well it will hold up. The secondary filter is 2 micron and is also washable and is much more sturdy being made of plastic.

It has 5 fan speeds (800-1400 CFM) and a timer for 2 – 8 hours in 2 hr increments, also can run continious. these features are controlled with a remote control. Uses a standard 110V outlet.

Seems to be fairly quite and does a pretty good job in my shop. I usually set it to run for 2 hours after I leave and I am happy with its performance. It has cut way down on the dust that settles at the end of the day, and has been a welcome addition to my shop and would recommend one. I wish I had not waited so long to make this purchase. Reguardless of what manfacture you may choose it is worth the investment. Hopefully this review is a help to my fellow LJ’s.

-- Dave from "The Sawdust Shed"

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