Wet dry vacuum filters and suction

Reviewers give a lot of weight to how well a wet dry vacuum captures dust -- and whether it uses bags or filters to protect the motor and keep the dirt in the tank. It's frustrating to vacuum dust only to see a lot of it exhausted right back out, and experts at Occupational Safety and Health Administration warn that lung damage can result from breathing in wood dust, sheetrock dust or other very fine particles.

If you pick a workshop vac that doesn't include a HEPA or Gore-Tex filter to capture very small particles, you may be able to buy one as an accessory (*Est. $30).  It's also a good idea to make sure you pick a shop vacuum for which fine-particle dust bags, often called sheetrock bags, are available. You can also minimize dust exposure by selecting a wet dry vac with a self-cleaning filter; some workshop vacs monitor the filter and clean it automatically when needed.

Although the majority of wet dry vacuums have adequate suction, some have more problems with emissions than others. In some cases, this can be corrected by using an add-on filter, but on some models, the lids simply don't fit tightly enough.


Wet dry vacuum features to consider

Reviewers suggest keeping the following in mind when choosing a wet/dry shop vacuum:

  • Look for a capacity that matches your needs. For collecting wood chips or other big cleanups, look for a 16- to 20-gallon tank. For most workshops and households, 10- to 14-gallon models have plenty of capacity, are easier to store and move around, and still offer adequate suction. For cleaning a house or car, smaller shop vacuums with tanks that hold 5 or 6 gallons are even easier to transport. Portable 1- to 3-gallon vacuums offer the most convenience, but they provide a lot less suction. Also consider storage space; different shop vacuumss of equal capacity vary in height, so some fit better in a closet than under a workbench.
  • The ideal hose diameter depends on what you want to vacuum. For general workshop pickup, such as vacuuming wood chips and shavings, experts recommend a 2.25- to 2.5-inch hose. Smaller hoses tend to clog. However, if you're using power tools in a workshop, you'll need a smaller, flexible hose that adapts to the dust ports on your tools.  Many reviewers recommend that workshops include a tool-triggered shop vacuum for collecting dust, plus a larger consumer-grade model for cleaning up big wood chips and other debris. Extra-long hoses are available for most models, but in most cases this reduces suction.
  • Two-stage bypass motors are designed to last longer. This can make a difference if you plan to use the workshop vac for extended periods as a dust collector. If you only plan to use a wet dry vac for short periods, it's not as important.
  • Some filters are easier to clean. Bosch, Porter-Cable and Festool wet dry vacuums offer the most convenience with their built-in filter shakers, which can be engaged without opening the units. Bosch and Porter-Cable wet dry vacs also have separate filter doors, allowing you to remove the filter to rinse it off without opening the larger canister.
  • Consider noise level. The best workshop vacs are so quiet that you can carry on a conversation while using them, and no ear protection is needed. Most new wet dry vacs have built-in mufflers, but they still vary greatly in sound level. Some experts say sound doubles with every six decibels. Most experts recommend wearing ear protection at 85 decibels, but it's wise to err on the side of caution. 
  • Drain valves or spouts make it easy to empty vacuumed liquids. Without one of these, you'll have to take the lid off and tip the tank to empty it, Remember, a big wet dry vacuum with a full tank of liquid can be heavy; if you plan to suck up liquids regularly, a drain plug is a must-have.
  • Do you need a wet dry vac with a pump?  If you plan to vacuum liquids frequently, you may want to choose a wet dry vac equipped with a pump, or invest in a pump as an accessory.
  • Wide-set wheels and a low profile help prevent tipping. If you have to haul your shop vacuum up and down stairs, models with large back wheels and a handle are easier to use.
  • Convenience features include cord wraps and onboard attachment storage. Users note that these features don't always work as well as advertised, however. It's a good idea to read owner reviews of models you're considering.
  • Do you need a blower? Shop vacuums that double as blowers are noisy and tend to exhaust more dust. Reviewers warn that when you use them to clean a very dusty room, they blow around the dust you're trying to vacuum. Some models feature removable lids that double as blowers, though these get mixed reviews for convenience.
  • Consider the cost of accessories. Many of the tool attachments, filters and dust bags designed for consumer-grade shop vacuums can be used on more than one brand, but higher-end wet dry vacs often require more expensive supplies. You may also want to budget for extra accessories -- not just dust bags or filters, but a longer, bigger or more flexible hose, or more extension wands for reaching high ceilings.

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