HEPA filters — Justifying the cost.
Tool Test: HEPA-rated shop vacuums by Asa Christiana #293-Tools & Shops 2022 Issue
I have to draw into question the value of articles like this to most woodworkers. Yes, I know that this is only a comparison of the various models of HEPA-rated shop vacuums. In and of itself, the article is solid and seems to focus on a serious problem in far too many woodworking shops. But does it? Or is it so far out of context as to be interesting, but of little actual value?
The glaring issue here is the outrageous cost! What percentage of average wood workers out there are going to pop for between $500 to $1,000 for a shop vac? Probably darn few — even if they are convinced of the importance of air filtration.
For one, I am thoroughly convinced of the need for exceptional air filtration in the shop. My father passed due to pulmonary issues which I am certain were primarily caused by his careless approach to woodworking dust control. Many was the time I would stop to visit and he would be barely visible through a cloud of walnut dust he was generating.
I believe in HEPA-quality air, but I don’t believe you need to spend $1,000 to get it. I am confident that those expensive shop vacuums hyper-clean the air that goes through them. However, I am just as confident that a lot of dusty air never makes its way through those units. Just stand back and – with the light just right – you can watch uncaptured dust wafting through the air.
My solution is to use a conventional shop vacuum with good filters coupled with an auxiliary cyclonic pre-filter to remove the bulk of the dust and chips. Additionally, I utilize what I call an “assembly table”. It is a 5-foot by 3-foot table (built to my preferred working height) built on high-quality, six-inch lockable casters. Inside this unit is an old furnace fan drawing air, first through three separate, 20″ X 20″ X 2″ pleated filters affixed to the exterior. After these three pre-filters, the air then goes though a 25″ X 25″ X 5″, whole house filter with a MERV rating of 13. I usually place this “assembly table” close to both the machine I am operating and the discharge of the shop vac. The final discharge from the “assembly table” should be just under the HEPA rating, but I am filtering many multiples of the amount of air — effectively the same amount as your house furnace.
Apples-to-Apples:
A HEPA rating is that 99.97% of particles with a size of 0.3 microns (micrometers) that enter the filtration system are removed.
Generally speaking, a MERV 13 rating removes 99% of particles with a size of 0.3 microns (micrometers) that enter the filtration system are removed.
APPROXIMATE COSTS:
(1) Used Furnace Fan – Free at almost any Heating/Cooling contractor
(3) 20″ X 20″ X 2″ pleated filters @ $8.00 => $24.00
(1) 25″ X 25″ X 5″ pleated filter => $32
(4) Swivel casters – lockable @ $15.00 => $60.00
1/2″ plywood and various scraps => $50.00
Misc. electrical & hardware => $50.00
TOTAL: approximately $216.00
Aside from the filtering aspects, this assembly table is one of the best things I ever built for my shop. It is a great beginners project that is well within almost anyone’s ability level. The cost is reasonable and many can probably construct it with cut-offs and scraps of plywood they already have. Breathe easy my friends — for a lot less than some articles suggest.
Replies
Hobby level folks probably not.
Pros and semi pros are buying them left and right.
Especially pros working on remodels, interior work and finish carpenters. Catching the dust at the source is pretty important as well as leaving things clean for customers.
Pretty fair to say you get what you pay for with many items like this.
I have the dewalt for work and its been great so far, works way better than a regular shop vac.
I purchased a Festool Dust Extractor (HEPA) when I purchsed my Festool Tracksaw. It is probably the best money spent (next to my minisplit HVAC) in my shop. My main motivation at the time of purchase was superior dust collection, but I have grown to appreciate the health hazards of fine wood dust particles and the protection HEPA filter affords me.
I also use it as a shop vacuum to keep the shop tidy. It does a fantasic job of dust collection on my Festool Tracksaw, two Festool Random Orbit Sanders and other vendor tools. Sanding used to be one of my least favorite woodworking tasks but the Festool products with dust collection and extended life of sandpaper reduces the time spent dramatically.
I just purchased a Festool CT-15 after reading the HEPA vac article. I have a nice dust collector but when using my Metabo six inch RO sander there was a coat of dust everywhere. I plugged the Metabo into the CT-15 and very little dust now. Almost none. That is worth $350.
I also use the Festool for general shop cleanup. I am a hobbyist and this works great for me. YMMV.
You should submit your build to FWW.
I have already submitted that article to another magazine.
As a young man who used to work in shops so filled with dust you would have thought it was a pea soup fog rolling in. To an old wiser man with lung issues I take my dust collection seriously and hopefully am teaching my sons to do it as well. I too have a Festool extractor I use for all my portable tools in addition to my central dust collection and air cleaner which runs anytime I'm in the shop. I can say I seldom see dust in the air but it's not the dust that you see that does the most harm so yeah I believe in HEPA filtration on all my dust collection systems. Your health both today and 50 years from now is not where you want to pinch pennies.
I wonder how many of us have the same story. My shop didn't have a dust collector for almost 20 years. There were times I couldn't see across the room because the dust was so thick. I think the worst was when I was ripping three inch maple on my radial arm saw. Really slow, and dust and SMOKE thick as pea soup.
I take dust collection very seriously now. I have a great DC and a ceiling mounted unit. And a Festool CT36 does a fantastic job with handheld tools.
If I could go back and tell my young self one woodworking tip, it would be dust collection.
I agree with everything JC2 said, but I would go back and tell his younger self not to rip at the RAS.
Yeah. I would never dream of doing that again. One kickback tore off the back end of the anti-kickback pawls, which were part of the blade guard. Another kickback shot across the room and halfway through the wall.
I have a list of things I would never, ever do again. That's one of them.
My radial arm saw went in the trash when sliding miter saws came on the market, much safe and more accurate.
I really have no issue with those who choose to drop that kind of money. And no . . . you do not necessarily, "get what you pay for." This is clearly a situation where I can do a whole lot better for a whole lot less.
Out of all the responses, I can most clearly align with ESCH5995, who says, "I too have a Festool extractor I use for all my portable tools in addition to my central dust collection and air cleaner which runs anytime I'm in the shop."
Although he does not directly say it, it seems like he agrees with me that addressing all of those unseen, fine particles of dust not captured in point-of-source HEPA units should really be addressed as well. While the air filtered through a HEPA unit is clean, the bulk of the air in your shop never goes through that small vacuum. What about the rest of the air you breath?
To be sure, there are many differing scenarios. HEPA filters are a good first step -- but only a first step. Like ESCH5995, my air cleaner (assembly table) "... runs anytime I'm in the shop." With several total air exchanges per hour at 13 MERV, I'm breathing more clean air than simply what is exhausted from the small HEPA filter units. While certainly an improvement over "the good old days", I am left with the feeling that Asa Christiana's article serves to provide a false sense of security.
To be clear here HEPA and MERV are ust 2 different rating systems for the filters themselves. The vacuums that are HEPA rated use a HEPA rated filter. You could use HEPA filters in a whole room air filtration system or or in principle a full size dust collector. You can buy HEPA filters to fit many existing shop vacuums for <$20. While I'm not trying to sell the expensive shop vacs I also believe they are supposed to be a higher quality build with more features such as an auto on/off feature, self cleaning filters and commercial duty parts, such as a continuous duty motor. I don't need it but a pro shop might. A quick search on amazon found a HEPA rated shop vac for $219 and even a Festool for for $369. So they don't all cost $500 - $1000. I would also add that the HEPA filters are usually designed to have a 2-3 year life span whereas furnace filters don't last nearly that long in my experience. In my garage shop that doesn't matter. To someone else, it might including someone who simply wants to generate less trash. Also HEPA filters fall into the MERV rating system with values from 17-20 if you want a direct comparison. And yes you want general air filtration as well as full scale dust collection. I have a $2,000+ central Oneida dust collector in my home shop and a general room air filter system so I do take it seriously. As to what particularte sizes and how much are most dangerous, I believe that is not yet fully understood so to some, more is better.
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