Friday, July 30, 2010

Filtration & Vacuum Cleaners

Bagged Vacuums

A bagged vacuum cleaner whether an upright or canister, is a vacuum cleaner that the primary filtration is a paper, cloth or synthetic bag located either on the inside or outside of the vacuum cleaner. This bag acts as the first level of filtration catching large particles and allowing the cleaner air with only smaller particles to pass through the pores of the bag.

In the past ten years most vacuum manufacturers improved their filtration and added an additional (secondary or final) filter to the bagged type vacuum cleaners. This filter is many times called a HEPA (High Efficiency Particle Arrest) filter.

For a HEPA filter in a vacuum cleaner to be effective, the vacuum cleaner must be designed so that all the air drawn into the machine is expelled through the filter, with none of the air or particles leaking past or around it. This is often referred to as "Sealed HEPA" or sometimes the vaguer "True HEPA". Vacuum cleaners simply labeled HEPA have a HEPA filter, but not all air necessarily passes through it. Finally, vacuum cleaner filters marketed as "HEPA-like" will typically use a filter of a similar construction to HEPA, but without the filtering efficiency causing poor airflow or less than desirable filtration. Because of the extra density of a HEPA filter, HEPA vacuum cleaners require motors with higher airflow and suction combined to provide adequate cleaning power.

Bagless Vacuums

Bagless type vacuum cleaners whether they are canisters or upright vacuum cleaners, usually have a HEPA or HEPA type filter attached to their exhaust also. Unlike the bagged type vacuums, bagless machines do not always have a primary filter as their first defense of capturing the large particles in the air that is being sucked into the vacuum. Some are designed with pre-filters made of washable foam and most also use centrifugal force to attempt to separate the particles from the air and then finally force the air through a HEPA or HEPA type filter to expel only cleaned air.

Cyclonic Assembly DiagramSince most readers are familiar with the Dyson brand of vacuum cleaners we will use one of their cyclonic units as an example of how bagless vacuums work. Keep in mind all bagless vacuum cleaners do work similarly the same. Dyson uses the term cyclone technology, but it is still simply centrifugal force that separates the large particles of debris from the air.

This type of filtration is the equivalent to a low quality filter or vacuum dust bag. Many (Not All) manufacturers also include a motor filter after the cyclonic assembly to catch somewhat finer particles prior to the air passing through the motor. Once the air has been cleaned of the large particles it still needs to pass through a HEPA filter to finish cleaning the air before it is expelled from the vacuum. All of these filters and even the centrifugal forces use energy and restrict airflow lowering your vacuum cleaner's efficiency.

Note about all information above: Vacuum cleaners in and of themselves, do not loose suction, That is a myth. Dirt clogging passageways and dirty filters are the cause of loss of suction. The suction from the motor is relatively the same in a new motor or a 10 year old one. Electric motors do not get “Tired” like gas powered engines.

What does all this mean to you?

When choosing a vacuum cleaner, filtration type and quality is an important part of the process. We find that allergy sufferers tend to pay closer attention to the filtration quality of the vacuum and less attention to the overall design and efficiency of the unit. If design and efficiency is over looked allergy sufferers might find themselves purchasing a vacuum that has a great filter but does not have the sealed aspect of the HEPA filter or a machine that does not have enough power to push the air through the filter thus lowering the overall cleaning effectiveness.

In addition, many people purchase a less expensive vacuum based on what the outer box claims being tricked by the simple term “HEPA” rather than doing research to be sure that vacuum is properly designed by a creditable company with the correct balance of filtration efficiency, cleaning effectiveness and ease of use.

Since the introduction of HEPA filters to the vacuum cleaner industry, most manufacturers have been forced to boost the power consumption of the motor in the vacuums to the maximum allowed by UL (United Laboratories) for household appliances just to accommodate the back pressure or resistance caused by HEPA filters. This has caused a great increase of energy consumption in mainstream box store vacuum cleaners and in doing so has caused more noise, shorter average life spans, and more heat generated by these electricity-hogging vacuums.


Vacuum cleaners are a major appliance in your home. They offer great results when they are designed and manufactured correctly. They do require the same amount of thought to purchase as does any other major appliance in your home. Don’t sell them short and please do your homework, finally; by all means ask questions when making a purchase.

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