The Basics: Canister Vacuums
A canister vacuum cleaner with a powerhead offers the best features of the upright and the standard canister. It has a canister's rolling tank (usually equipped with a tool caddy), hose, and nozzle, combined with a powerhead outfitted with an agitator similar to an upright's. Lots of tile and wood will be maintained well with a suction-type canister. An even mixture of surfaces might be best cleaned with a powerhead canister.
For versatility, the brush roll on a powerhead canister can typically be switched off for safe operation on bare floors. Canisters are typically easier to push than uprights and are easier to maneuver on stairs. Hoses that swivel at the base are the best option for ease of use and maneuverability.
Most canisters have some type of filtration system, onboard attachments and retractable power cords. Most feature collection bags, but a few bagless varieties are offered. Units with suction control are great for the safe cleaning of fabrics and rugs. Although uprights are favored on store shelves, canisters are slowly gaining in market share and popularity, and have always maintained a loyal following of tried-and-true canister users.
How to Shop
When you shop for a powerhead canister, carefully examine its brush roll. Some units have independent motors that let them dig deeper into thick-pile carpet. Others have turbo- or suction-driven brush tools, which have less strength but might still be adequate for your needs.
Look for features that suit your needs, such as a HEPA (high efficiency particular air) system if you have allergies; good tools if you have a lot of furniture, molding and drapes to clean; longer cords and hoses if you have a large space; and lighter-weight machines if you need to transport the unit between floors. Try out a vac and make sure the attachments are easy to use, the dirtbag is easy to empty, and the unit is easy to maneuver.
More and more vacs include a HEPA system, which refers to a sealed filtration system that retains almost all (estimates range from 99.97 to 99.99 percent) of the dirt, dust, pollens, and mites in the air. It supposedly filters better than any other system and it is used in hospitals. Don't be fooled by such special features, though. Even though a vacuum may have a HEPA suction system, that doesn't mean it is a perfect performer. For example, a vacuum's ability to pick up all the dust, dirt and pollen possible depends just as much on the design of the whole vacuum as on its filter system. The same applies for dirt sensors. They only let you know when the vacuum has stopped picking up dirt, not necessarily whether there is still dirt left in the rug, because it doesn't actually detect the dirt in the rug.
Canisters can be found in almost all the places uprights can be bought but there likely won't be as many models to choose from.
