In the previous section, we mentioned that older, stand-up vacuums that use bags may not be effective at eliminating dust mites, dirt and animal dander, which contains hair, skin flakes and traces of feces or urine.
Many people don't like having to keep up with a supply of vacuum bags and might push off vacuuming to another day when they realize they'll have to run to the store to get more bags. Worse yet is having to open the vacuum and examine the bag to see if it's full. Yuck!
There's one sign your vacuum bag is full: decreased suction power. As a vacuum bag fills up, the vacuum's suction decreases. You may think you've vacuumed an entire room before realizing you've just been operating a four-wheeled device without suction power.
Bagless vacuums have grown in popularity for these and other reasons. Unlike bagged vacuums, bagless vacuums use a built-in, removable dust cup that collects dirt and allergens from the air being forced through the vacuum. It does this by using centrifugal force to whip the air around the cup, forcing debris outward to the cup's walls and allowing air to escape while the debris falls off the walls and into the cup. Other than this, the designs of bagged and bagless vacuums are fairly similar. A fan pulls air in through an intake valve, runs it through a filtering system (either a bag or the chamber with the dust cup), and then forces air out through an exhaust valve.
An advantage of bagless vacuums is not having to open the vacuum case to find out if the collection device is full -- you can see directly through the clear plastic cover to see if it needs emptying. Additionally, manufacturers of bagless vacuums boast their vacuums -- unlike bagged vacuums -- maintain suction power no matter how full the cup is. However, in practice, bagless vacuums usually do lose some suction power as the dust cup becomes full.
The primary advantage for allergy sufferers is that vacuuming can be done anytime without any worry as to whether spare vacuum bags are somewhere in the house. You can simply empty the dust cup, replace it, and you're ready to vacuum.
There are big drawbacks to bagless vacuums, too. We'll discuss them -- and a filter that might change your allergy-plagued life -- in the next section.