Pro-level wet dry vacs are tool-triggered: They have an electrical outlet for plugging in a power tool and connecting its dust port to the shop vacuum's hose. Once configured, the auto-start feature turns the vacuum on and off in sync with the tool, and dust goes straight into the wet dry vac. You can often buy an accessory to make an ordinary wet dry vac tool-triggered, but the extra noise can be punishing during long sanding sessions. Not only is the tool-triggered feature convenient for easy dust collecting from woodworking tools, but it also helps protect woodworkers' health: Wood dust was added to the U.S. government's list of known carcinogens in 2002. To prevent dust-inflicted maladies, most new tool-triggered wet dry vacs now adapt for a HEPA filter to capture particles as small as .3 microns. Experts also advise you buy a dust separator for your wet dry vac, or select a model with an automatic filter-cleaning system.
One such self-cleaning workshop vac is the 13-gallon Bosch Airsweep 3931A (*Est. $535), which gets top ranking in this category from most experts. After switching off the attached tool and vacuum, the Bosch 3931A's cleaning system automatically starts up to shake dust off the filter. Experts say they are impressed by how the Bosch Airsweep workshop vacuum restores suction almost to full power after self-cleaning, regardless of how badly the filter had been clogged. Reviewers also like the Bosch Airsweep 3931A's drain for liquids and automatic shut-off function for when the liquid reaches its maximum level. You can adjust its power for use with higher-amperage tools and can take full advantage of a 20-amp circuit.
The Bosch Airsweep 3931A does have a slightly narrower hose, which is 2.25 inches in diameter than many pro-level wet dry vacs. In a recent Fine Woodworking vacuum comparison, experts cautioned that using the Bosch vac to suck up big wood shavings could result in clogs. To step it up to 2.5 inches, or down to 1.25 inches, you can separately purchase a hose adapter (*Est. $7). Noise level is another point of concern with the Bosch Airsweep 3931A. While review sources report conflicting noise levels ranging from a tame 69 decibels to a devastating 91 decibels, it is worth remembering that the tools triggered by such a wet dry vac will increase the noise output: Ear protection is a must.
After a 2009 redesign, Fein Turbo series shop vacuums are equipped with drains and adjustable suction dials like the Bosch 3931A. However, Fein wet dry vacuums still lack self-cleaning filters. Where the Fein Turbo shop vacuums score the most points with users and experts alike is in the noise department: with a rated noise level of 57.8 decibels at 3.5 feet, the 9-gallon Turbo II 9-20-25 (*Est. $300) is one of the quietest wet dry vacs on the market. Many reviewers say they appreciate the durable construction of Fein vacuums, though a few reviewers express frustration over the absence of onboard hose or attachment storage. Fein Turbo attachments, dust bags and HEPA filters typically must be purchased separately, as is the case with most pro-level workshop vacuums.
Many of the tool-triggered wet dry vacuum reviews that we uncovered discuss Festool Cleantec (CT) vacs, in particular, the discontinued 8.7-gallon CT 33 and 5.8-gallon CT 22. Reviewers praise these older Festool CT models for their compact design, powerful suction and relative mobility given their notable heft; the empty CT 33 tips the scales at 32 pounds. Increasing canister capacity without increasing overall shop vacuum weight is one of Festool's achievements in designing its new generation of CT shop vacuums: The CT 36, the recently released successor to the CT 33, weighs a lean 29.8 pounds in spite of its roomy 9.5-gallon canister capacity. The 6.9-gallon CT 26 replaces the CT 22. The new CT workshop vacuums also improve upon the old versions with self-cleaning filter bags, built-in hose storage, and single, modular HEPA filters. While reviews of the newer Festool shop vacuums are beginning to show up, the few CT 36 and CT 26 reviews from Amazon.com users are quite positive.
Both Fein and Festool call their models "dust extractors," and they are primarily designed for dust collection from sanders. Though they can vacuum liquids, their small diameter hoses can clog easily; you may want to buy another wet dry vac or purchase a wider hose attachment for general workshop cleanup.