Vacuum Cleaners Discussions

I've come across this spec in Dyson reports and also for Central Vacs. However most other upright vac vendors call out motor power instead. Can anyone explain to me why there are two power ratings out there for vacuums? I understand what air watts are but I don't understand why there are two different specs. To use a car anaolgy is this like Horsepower vs Brake Horsepower?

Hi,

To my mind its all unnecessary.  It's all an example of --"If you can't dazzle 'em with brilliance, baffle 'em with BS."

According to the One Look" online dictionary an air watt is:

an engineering unit used to express the effective cleaning power of a vacuum cleaner or central vacuum system. The air watt is practically the same as the ordinary watt. Measurements of vacuum power, however, are computed from English units using the following formula established by the American Society for Testing and Materials (ASTM): power in air watts equals 0.117354·F·S, or very nearly F·S/8.5, where F is the air flow in the system in cubic feet per minute (CFM) and S is the suction pressure in inches of water column (in WC). This definition makes the air watt equal to 0.9983 watt.

Hope you understand that -- I don't.

Best,

Venson

Venson wrote:
I follow the math fine. Looking at this air watts takes into account air flow and suction. Amp power ratings measure the potential and power useage of the motor only, much like the Brake horsepower rating for cars. Which makes sense because if that were not the case any 12AMP motor would have a 1300+ airwatt rating which is obvisouly not the case. I think that clears things up a bit. I'm still a little confused as to how air watt ratings are tested though. With all things considered two brand new vacs with like powered engines and similar flow/air routing would have the same air watt rating. Are central vacs and dysons tested over time and then give a averaged air watt rating? In the telecomm industry we have average Bit Error Rates which is a number derived over time to provide 99.999% availability of a circuit. Is this what air watts is then for vacs?

Hi again MrApollinax,

I am lousy at math -- I was bitten by a subtrahend at the age of ten and have never been the same since.  Nonetheless, when it comes to adding up what counts, I can assure you that numbers mean nothing if the machine in mention is not well-designed.  How well a vacuum is designed to consistantly get the most out of its suction power wherever applied is always the issue.  Air watts, water lift and all those terms are cute but of no real worth in judging actual cleaning potential if motor power is the main focus and worthwhile design is an afterthought.

What I never seem to hear much of is what amount of suction and/or air flow is actually being delivered at the hose or down on the floor. 

Regards,

Venson

Air Watts (IMO) are basically marketing mumbo jumbo.  Most of these ratings are taken at the motor, sitting on a bench and not attached to any vacuum.  The minute you put a motor in a can and add a bag or filter all of the specs will change.  You may see 6 different brands of vacuums with all the same air watts but because filtration levels vary all could conceivably perform completely different at the end of the hose.  If you think more air watts means more power, see if you can figure this one out....
Last year on the Beam website  a 550 airwatt machine was rated up to 10,000 square feet where as this year the 600 airwatt machine is rated to 7000 square feet.

Dusty

This airwatt stuff reminds me of,when we thought we had all the answers,they changed all the questions,All you really have to do is put your hand at the end of the suction hose and feel it. The usual customer reaction is WOW,mine dont do that.

MOLE

mole wrote:

Hallelujah!

Venson

mole wrote:

Did that back in the 50's with the canns and tanks.  If the hose end stayed on your palm with the vacuum running, it was worthy of buying and selling!

Carmine D.

CarmineD wrote:

Sounds as if all those Hoover customerws were no told this.

dusty wrote:

Ah but, are they not usually specified  in the adverts (at least here in the UK, anyway) as,

eg; "410 AirWatts (measured at hose end, when empty: IEC60312, or whatever)". I would presume that the cleaner is tested as you would find it in its box, with hose, without floor nozzles.

Trilobite wrote:
Here (Canada) most central vacuum systems give the Air Watts in their brochures or even on the front of the unit.  In both cases, it's motor only, not installed in a canister and no hose attached.