Vacuum Cleaner Ratings/Specifications
The main things I look for in selecting a vacuum cleaner are:
-Motor(s)
input power (where the biggest consumption of the rated amperage occurs.)...Always compare: Watts:Watts...Or...Amps:Amps
(Conversion formulas: amps x 120v=watts...watts/120v=amps)
-Water Lift (called "sealed suction")... How many inches a totally sealed motor will vertically lift a 1" column of water. Good indicator of a vacuum cleaner's ability to lift/pick-up dirt/debris.
(90", or more, is considered the 'best'...But the caveat is: Vacuum cleaner prices go up exponentially as the lift-rating increases, though
-Air Flow (rated in CFM)...Probably the most important rating/specification for a vacuum's cleaning ability. The more above 100 CFM, the better.
As to:
-
Horsepower (Often called “Peak Horsepower”):
This rating is obtained by removing the fan(s) from the vacuum motor and subjecting it to the maximum load possible before the motor burns out. Then, a complex formula is applied to come up with a Peak Horsepower rating. This specification is meaningless in terms of evaluating the cleaning ability of a vacuum cleaner. This is a rating that's used primarily for marketing purposes.
As such: Here's a quote from ShopVac (explanation of vacuum cleaner terminology):
"Horsepower Rating...Peak horsepower is the maximum output horsepower of a motor determined from a laboratory dynamometer test. Since peak horsepower is outside the normal operating range of a vacuum cleaner, it may not be indicative of actual air power differences when comparing two cleaners".
-
Air Watts...Not to be confused with Air Flow!!
This is considered an attempt to rate a vacuum cleaner's: output power vs. input power...Just another way to cause confusion, it seems. (But even ShopVac still lists it?!?!)
[Formula used to obtain Air Watts: (CFM x Lift)/8.5=Air Watts=1 Watt...That figures!]
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Then there's always the filters, tank-size, hoses, and attachments that may reduce the efficiency of a vacuum cleaner
somewhat.
-Boils down to and depends on one's budget/needs in the: Vacuum Cleaner purchasing decision process...IMO.
BTW:
The most NEC-allowable amperage for an appliance, such as a vacuum cleaner, on a
regular household (110-120/130v) circuit is 12 amps.
-Good Luck in finding a unit for your detailing purposes!!
Bob