Science & Mathematics » Physics » Is power use a useful way to measure by which to compare appliances, and if so why?

# Is power use a useful way to measure by which to compare appliances, and if so why?

• It's one of many items to compare to select an appliance. Probably a minor one.

High power can be a + or it can be a –.

Light bulbs, for equal light, you want low power.

Audio power amplifier, you want high power delivered to the speaker, and low power drawn from the mains.

Electric cloths dryer, you want high power.

bottom line: it depends.
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• It is a measure. But it only becomes useful if two appliances are performing the same job.
Even then the difference in power can be due to one doing the job faster.

So two pumps, one uses 800 W the other 500W. Does the higher powered one move more water? Or do they both do the SAME job.
In the example I quote I have these two pumps and the 500 W pump moves MORE water than the 800W one in my situation.
So the power consumed actually shows me that my 500W pump is better designed and more efficient than the other pump.
So guess which one I would buy more of.

Of course the 500W pump also cost more. So it would only be useful for people like me where I am pumping the water for hours every day as part of an irrigation system.

If two appliances are designed identically then the higher powered one will do MORE in a given time. ( more light, more heat, cool more etc).
If two appliances use a different technique and give the same output then the lower powered one is more efficient and hence "better".
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