HEPA cleaners must contain a sealed filter unit so that all the air drawn into the filter expelled through the filter too and that none of the air leaks out any other way. See How do HEPA filters work article.

HEPA Vacuum cleaners come in two basic styles, upright and canister (cylinder).

Upright

An upright HEPA vacuum is a vertical machine which performs a single unit. Some have various attachments and hoses to reach difficult areas. Upright vacuum cleaners tend to leak dusty air back into the environment more than canister machines. However, the beating action of the brushes makes them efficient at stiring up dust for removal.

Canister (cylinder)

Canister (sometimes known as cylinder) HEPA vacuum cleaners are usually smaller than upright models and have a compact designed case designed to roll along behind the operator as the floor is vacuumed using a hose and nozzle. Canister HEPA vacuums have the advantage of being able to reach to areas that are difficult to get to and to be usable on furniture and curtains as well as carpets and flooring. Some canister cleaners are often much more powerful than upright models because the nozzle can be powered by its own electric motor.

Cylinder versus upright vacuums

Each type of cleaner has its fans. The biggest disadvantage of upright cleansers is that they are big, heavy machines and are difficult to manoeuvre. It’s also very difficult to get them to lie flat to fit under furniture. Also, the tools of upright hoovers are limited and are not integral to the main machine. However, upright hoovers have been shown by some research to be more efficient, mainly due to the beating action (although some cylinder vacuum cleaners now have this action in the cleaning nozzle).

Cylinder vacuum cleaners are more compact, lighter and easier to move over the carpet. In newer models, all the tools are on board. However, research has shown that cylinder cleaners can be less efficient - especially if they do not have a power driven nozzle.