vacuum cleaners power.

[Dajstar]

How is the suction power determined on a vacuum cleaner , is it the wattage of the motor or is it the air wattage , or both ?  Some are labelled with air watts and some are not.

[KARL]

This is about something where no intelligent unit of measurement exists, rather like the "Tog" of "downies" with their curious "feather and down" as opposed to "down and feather" distinctions - some manufacturers try to present an edge over the competition and/or appear much more intelligent (for which read "better at jargon but misleading"). The point is that some machines can build up higher "zero flow" suction (vacuum) than others but are not able to shift as much air at any given flow rate. The latter is what is of practical value (but over a range of pressure differences). This is going to sound corny, but when it comes to the usefulness of vacuum cleaners you have to "suck it and see". These things come in so many different models, etc. that what suits you is what makes you happy but it might not suit others.

[KebabMeister]

In general terms bagless high wattage are normally have better suction that bagged/lower wattage ones.