Shop Vac vs. Dust Extractor vs. Dust Collector: What to Buy First
Shop Vac vs. Dust Extractor vs. Dust Collector: What to Buy First - A step into the workshop.
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Yo, let me tell you a story. I'm walking down my block in Brooklyn, and there's a slab of walnut leaning on a brownstone stoop. Somebody's renovation castoff. I haul it home. The looks I get on the subway. A guy in a hard hat asks if I'm moving a door. I get it into the second bedroom, the one my landlord thinks is for guests, and before I even plug in the moisture meter I know the fantasy is dead. No space. No dust collection. No truck for the real machine I actually need.
So I bought a shop vac first. Then I learned the hard way that the shop vac, the dust extractor, and the dust collector are three different machines that do three different jobs. Buy them in the wrong order and you buy the same dust twice. Let me save you the tuition.
Suction and Airflow Are Not the Same Thing
This is the whole ballgame. A shop vac is high suction, low airflow. That's why it'll suck a screw right off the floor through a narrow hose. The Handyman's Daughter (Vineta Jackson) puts it plainly, and CNC Cookbook says the same. A dust collector is the opposite: high airflow, low suction. That's why chips and light sawdust float down the wide hose, but it can't pick up your dropped wrench.
High suction doesn't pull fine dust away from your face. It grabs a sock. Airflow is what moves the cloud. That's why your box store vac can feel like it's ripping the floor off and still leave you coughing.
The Numbers on the Box Are Lying to You
WOOD magazine tested this. Their finding, from Craig Ruegsegger's whole-shop dust collection piece: halving the manufacturer's claimed CFM gives you a truer measure of performance once the machine is attached to ductwork. So a collector advertising 1,300 CFM realistically behaves closer to 650. The box number is not your number.
It's also hard to check. WOOD notes most manufacturers don't publish fan curves, the plots you'd need to match static pressure against required CFM. You can't verify what they won't show you.
Then look at the Craftsman 16-gallon, 6.5 peak-HP wet/dry vac. Craftsman's own product page publishes no CFM at all. And its footnotes concede the two numbers printed biggest on the box mean nothing you think they mean: gallons reflect drum volume, not collection capacity, and peak HP is a laboratory dynamometer figure. The one number that would let you compare it to a collector is simply absent.
Filtration Has a Real Standard, and a Fake One
HEPA is a certified thing, and "HEPA-type" is not. WOOD's rule: look for filters labeled HEPA, which are third-party certified to trap at least 99.97 percent of 0.3-micron particles. Avoid "HEPA-type," "HEPA-like," or vague "removes up to 99 percent" claims.
The EPA's page on MERV ratings backs this up and gives useful scale. MERV reports capture of particles from 0.3 to 10 microns per an ASHRAE test method. MERV 13 catches at least 50 percent of 0.30–1.0 micron particles; MERV 16 catches at least 95 percent across the bands. HEPA is the top rung. Here's the part most guys miss: 0.3 microns is the worst case for HEPA, not the best. Particles bigger or smaller than that get captured even more efficiently.
Why care? The Wood Database (Eric Meier) flags the invisible 2–10 micron dust as the most damaging, the stuff that floats and lingers after the tools stop. WOOD gives you a way to picture it: it takes 1,300 particles of 0.3 microns side by side to span 1/64 inch. Your lungs don't need a weather report for that.
What Each Machine Actually Does
Shop vac. Grabs screws, spills, wet or dry, bulk sawdust off small tools. Most versatile of the three per Jackson and CNC Cookbook. What it doesn't do is handle fine dust without an upgraded filter. CNC Cookbook is blunt that the average shop vac lacks the right filter; a HEPA filter or drywall dust filter helps.
Dust extractor. Jackson describes it as similar to a shop vac but moving more air, with better filters typically HEPA grade, portable enough to carry to the job. It's built for handheld tools. WOOD is explicit: random-orbit sanders and routers belong on an extractor or HEPA shop vac, never ducted to a collector, because the small dust port chokes off a collector's airflow. That's the principle behind your question about CFM at the sander. Small ports throttle everything upstream of them.
The catch is cost. CNC Cookbook says an extractor runs three to four times what an equivalent shop vac does. A Festool CT 26 EI HEPA, per the retailer Floor Mechanics spec table, is rated 138 CFM with 96 inches of static water lift, a 979-square-inch filter, and a $999 price. The CT 48, per Taylor Tools, is 137 CFM and $1,199. That's a tenth of the 1,300 CFM a ducted shop system wants. It's not a small collector. It's a different job.
Dust collector. For stationary machines. The Wood Database lists the table saw, jointer, planer, bandsaw, and drum sander; WOOD calls these the tools that demand the most. WOOD's sizing floor for a whole-shop ducted system: at least 2 hp, a 12-inch or larger impeller, and a 1,300 CFM advertised rating. Some 2-hp units run on 110 volts; anything larger needs 220.
The CFM-per-tool table CNC Cookbook reproduces is the arithmetic that humbles you. Table saw 350 CFM. Belt, disc, or drum sander 350–550. Planer up to 13 inches 400, and 14–20 inches 785. Now halve your collector's advertised number per WOOD and see if it still covers the planer. Buy too small and you know exactly how it ends.
The Buying Order
Start with what makes the dust you breathe most. For most of us in a spare bedroom, that's sanding. WOOD says handheld tools can't run on a collector anyway, and The Wood Database flags that 2–10 micron cloud as the long-term hazard. An extractor-class machine, or a shop vac with a real HEPA filter, addresses your highest exposure first.
Only then buy a collector. Size it for ductwork, not the box. WOOD's floor applies. Don't buy a collector expecting it to serve a sander, and don't buy an extractor expecting it to run a planer. Both mistakes are stated plainly by WOOD and CNC Cookbook. And never buy on tank size or peak HP; Craftsman's own footnotes just admitted those are marketing.
Cheap wins before new machines. WOOD says an aftermarket filter with more surface area can actually improve a collector's CFM, not just filtration, because it reduces resistance. Seal every leak around filters, bags, fittings, and ducts with tape, caulk, or weather stripping. A cyclone pre-separator keeps most of the chips out of your filter and keeps airflow constant, per WOOD and Jackson.
One honest wrinkle. WOOD tested Oneida's Supercell and reported nearly ten times the suction of a standard collector and two to three times the CFM of a shop vac, with HEPA, running 4-inch duct and 2-1/2-inch hose. It's a single-magazine first look, explicitly preliminary. Present it as that, not as a category you can bank on.
So What Do You Buy First
If your hours are sanding, buy the HEPA machine for the sander. Full stop. Your lungs are the stake, and none of the numbers on a wet/dry vac box will protect them. Live with the small-shop constraint: the second bedroom, the thin walls, the neighbor who already hates your router.
Save the collector for when the planer and the table saw start earning their floor space. Then buy past the minimum so you don't buy twice. The hobbyist who spends $999 on the wrong box is the guy who eventually spends twice. Sequence it right and you spend it once.