Uploaded March 2020 | Updated September 2026, 1 week ago

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I bought two shop vacs and measured the horse power. The results will surprise you! It feels so good to know the truth.

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Notes:

1. The ultimate guide to using electric motors.
youtu.be/SrPHQh-M3pM

2. How to measure horsepower in the home shop.
youtu.be/1Pd0lUKWe7o

3. Wet Dry Vac review by popular mechanic
popularmechanics.com/home/tools/reviews/a4538/4220931


Answering common questions.

Why does my shop Vac draw less power when I block the hose?
It is the reverse of what you might think. When you cover the end the air "around" the impeller is no longer trading places with new air... and it is already at speed so it doesn't need to be accelerated. That means the motor has to do less work... the power needed goes down and the speed goes up because it is "easier" for the motor to push air that is already moving. That second part is unique to universal motors. That is the speed going up noticeably. When you release the hose end new air comes in and it takes more work to get that air up to speed... thus the impeller slows down and the motor is working harder (more horsepower)





Technical corrections

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