How to calculate power consumption of electrical or electronic home appliances?
Question by Mamoon R: How to calculate power consumption of electrical or electronic home appliances?
Best answer:
Answer by TV guy
Every device has a UL label that specifies its power consumption in Watts. Add all these together.
What do you think? Answer below!
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Sorry, TV Guy, but not every device lists it’s wattage. Mostly only heavy duty appliances (hair dryers, toasters, microwaves, etc) will list actual wattage.
TV Guy is right that all electrical appliances will show their usage rating; but that is often listed as voltage and current and not wattage.
To get the answer, you need to do some simple math.
Voltage x Current = Watts
If a device at 120V (USA House Voltage) draws 1 Amp, it will use 120 watts. 120v x 1a = 120w
Sometimes the rating is listed in VA (volt-amps). While not exactly the same as watts, it is close enough for most estimates. This is usually restricted to motors, where the voltage and current are not always in phase (but that’s a whole different lesson in electronics).
Sometimes your electronic device will have a power adapter module to convert 120 VAC to some other VAC or VDC. The rule still applies.
If the output of the module shows 12VDC @ 500 mA, then the device will 6 watts. 12v x .5a (500mA = .5A) = 6W
There are always some resistive losses in the power module, so I’d add 10% to any device using a power module. In the example above, 6.5 to 7 watts would be a good estimate.