The term “power” is often used to describe the value of one vacuum cleaning machine over another.  It is a ubiquitous term that is used almost exclusively to evaluate machines, yet it has no associated measure by which a machine can be evaluated.  The term is used as a descriptor of a machine’s capability.  Interestingly, even though there is no standard measure associated with the term, when it is used in conversation it is well understood.

Many sales people have wrestled with the term power and pushed engineers for some discernable measure for comparison to present one machine as having more “power” than another.  Engineers have pushed back saying there already exist many measurable elements, another standard is not needed. Use one of the standards already in use.

So, the dilemma continues with marketing executives touting different measurable aspects of their machines, and other machine marketers using yet a different group of elements to describe their machines.

The end result is a confused purchasing public unable to easily measure one machine against another.  This causes decisions to be made on other grounds like color, how one will look when using the machine, is there a picture of a baby on the box, etc.  The purchasing public has no metric for comparison, should there be any surprise that poor quality machines are sold every day?

In an effort to quantify and establish a measure that can be used, read on to see how the manufacturers evaluate their machines and what can be used to compare.

Manufacturers want to represent their engineering decisions in the best light as possible when marketing their products.  So, they look for design choices that make them stand-out against their competition.  Or, they look for design elements that can’t be compared to other like-engineered products.

Manufacturers want to represent their engineering decisions in the best light as possible when marketing their products.  So, they look for design choices that make them stand-out against their competition.  Or, they look for design elements that can’t be compared to other like-engineered products.

If a manufacturer wants the consumer to think their product is powerful (‘powerful’ equates to ‘good product’ in vacuum-speak) they will represent power using  a measure other than what other similar products use.

This way you have to “take their word” that what they claim is true.  Of course, the measure used is usually represented by a real measurable element which gives the claim a bit of authenticity.

This is a dilemma, but not an insurmountable one.  Fortunately, The number of elements that are measurable are not infinite.  There are only a few that can be associated with the ability to move contaminants in an airflow.  They all have to do with energy or the affect energy has on airflow.

There is only one mechanical way in which manufacturers represent their machine’s airflow.  The term used is  Cubic feet per minute (CFM).  However, some manufacturers hesitate to use CFM because their machines are smaller and have a lower CFM rating. So for those manufacturers they modify CFM into a hybrid term of Air Watts (AW) or just watts / amps.  Both watts and amps are a bit ambiguous since they refer to total energy used and that can be misleading.

Cubic Feet per Minute (CFM) is a representation of airflow as it traverses the fan assembly.  Keep in mind airflow can have some mitigating factors such as: accessory design, diameter of piping in and out of the fan assembly, Surface area of the exhaust, and cleanliness of the filter medium.

Generally a CFM rating is a best case measurement without any hoses or attachments on either end of the fan assembly.

As a general rule a CFM rating between 60-100 is normal for most machines.  The rating is considerably different (greater) when considering whole house systems that make use of hundreds of feet of hose.  These machines must have a much higher CFM because of the hose length and the attachments necessary to liberate contaminants from a resting position in carpet.

This can also be translated to a litre format using :a cubic foot equals 0.0283 cubic meters or 28.3 cubic litres.

AW stands for Air Watts and is a measurement of a sustained vacuum and the corresponding energy (measured in watts) used to maintain a vacuum.  In the air watts measurement it should be noted that a measurement made at high altitude will yield differing results from a measurement taken at sea level.  In the Air watts measurement the formula needs the CFM rating and the Inches of  H2O (sealed suction).

AW=(Inches of H2O x CFM) x 0.117254

A typical canister machine should average at 220 AW, Upright machine  200 AW, Premium  dyson brand 270 AW

This is a measure of power used by the vacuum machine in total.  It is not a very accurate measurement of the airflow generated by the vacuum cleaning machine.  If there is a light or power assist, or a power head the total number of watts will increase and have no effect on the airflow of the machine.  This is a good value to keep in mind for the cost to operate, or the draw against a generator or other power supply.  If you do not know the wattage rating it can be calculated using the formula: Volts x Amps = Watts.

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