4 ways to determine the power consumption of electrical appliances

When receiving a receipt for electricity, you sometimes wonder where this amount came from and why the meter counted so much. To make sure that the equipment and electricity meter are working properly, it is necessary to determine the energy consumption by available methods. To do this, our arsenal assumes the presence of a multimeter, an electricity meter or clamp meters. So, below we will tell you how to determine the power consumption of the device at home!

We look in the passport

The first way is to look in the passport of the appliance. All factory units are supplied with a label on the case, instructions and a passport with a guarantee. These books indicate the scope, operating conditions, and technical data.

Heater passport

Above is a small fragment of the passport data, or rather, a table with data from the model range of convector heaters. Column No. 1 indicates the current passing through the device, the second column indicates how much power the device consumes when one TEN and two are turned on. Here's an example of a heater using a passport, you can easily find out the power consumption of the device. Similarly, you can determine how much the TV or even the LED lamp consumes.

Ohm's law to the rescue!

The second way is to determine the current strength and calculate the consumption using the formula, Ohm's Law. We take a multimeter, turn on the dialing mode or measure resistance. We measure resistance R ten.Now we can calculate the current that can pass through the system A ten. To solve the formula, you need to know the voltage, but it is 220 volts in the home network.

Ohm's law

After the current is found, you can determine the power of the device. For this, we multiply the amperes by volts.

Calculation of electricity consumption

More about how to use a multimeter, you can find out from our article!

We use an electric meter

The third way - almost all metering devices are equipped with a light indicator, the number of flashes means some power consumption imp / kW.


We turn off all consumers in the apartment, leave only the device of interest connected. Within 15 minutes, we count the pulses and multiply by four (to get the quantity per hour). Having learned the number, divide it by imp / kW and find out the power of the unit.

You can also record the meter reading, turn on the appliance, the consumption of which we are trying to determine for some time, preferably for an hour. We record new readings, we take away the old ones from them, as a result we find out the approximate power.

An electronic meter allows you to see all the parameters in real time: current, power consumption, network voltage, by sorting through the metering device menu. About, how to take readings from an electric meter, we told in the corresponding article!

An analogue of an electric meter can be a household wattmeter, with which you can quickly and accurately determine the power consumption of electricity by the device. The video below demonstrates the operation of this device:

Current clamp meter

If there are current clamps, it is easy to determine consumption. To do this, it is necessary to measure the current in one of the conductors connected to the device.

Current clamp

The video below clearly demonstrates the method for determining the power consumption of electric current by the example of a conventional incandescent lamp:

If there are no current clamps at hand, then it is better to use a conventional tester. Every electrician, even self-taught, should have this meter in his arsenal.

So we looked at how to determine the power consumption of the device by current, formula and meter readings. We hope that the provided methods were interesting for you and were useful in the independent determination of the parameters!

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