Dyson invented this type of vacuum cleaner that operates without a conventional dust-collecting bag, but instead uses his trademarked Root Cyclone technology. This separates dirt and dust particles from the air stream by the use of centrifugal force and deposits this debris into a transparent container. This compartment can be easily removed when it is seen to be getting full and the contents dumped into a rubbish bin.
A bag type vacuum cleaner has a sealed dust bag that is disposable and has to be fairly regularly replaced. The bag captures the dirt while you vacuum and filters and separates the dirt from the air going through the machine; it then deposits this dirt in the bag. Once the bag is full you remove and discard it. The problem is that people do not always realise when the bag is full; once the bag is full the machine loses suction – which might not be immediately obvious, but will seriously affect the machine’s performance. The upside is that all the dirt is safely trapped in the bag that can then be easily disposed of. However, removal of the bag without any spillage can sometimes be tricky and the card/paper type bags if very full can sometimes split; not a good experience. Also of course the bags have to be purchased, although generally they are not very expensive.
With a bagless vacuum cleaner you do not need to worry about cleaning the machine very often because the dirt and debris is in clear view inside of the container. When the dirt reaches the fill line, you empty the container. When you do clean it some machines require you to brush, wash and fully dry their filters – or worse, completely replace them.
Bagless machines do a very good job of removing household dirt and dust, and the idea of not buying replacement bags can be quite appealing. Additionally, if you accidentally vacuum up something you did not intend to dispose of you can easily retrieve it from the container.