How To Calculate Power Consumption Of Any Appliance

Have you ever wondered how much electricity your TV consumes per hour or how much power a home light bulb uses? If you don’t know like most people, don’t worry because we’ll explain it in this article. Here you will learn how to calculate the power consumption of every electrical device in your home. By knowing this, you’ll much better understand the consumption of appliances that run on electricity in your household. So, let’s get started!

So How To Calculate the Power Consumption Of Any Appliance? The power consumption of any electrical device can be calculated by multiplying the watts (W) of the device with the number of hours it worked (also known as operational hours). This gives us kilowatt-hours (kWh), which indicate the appliance’s total power consumption during its operation.

For example, a washing machine is a home appliance that is used in almost every home. When it comes to washing machines, you should know that 80 to 90% of the electricity during operation is used to heat the water. An exception to this is when the washing machine is directly connected to a source of pre-heated water.

It should also be noted that older models of washing machines consume much more energy and water compared to newer models that are much more energy-efficient. The washing machine consumes between 400 to 1300 watts on average, while the newer models that have Energy Rating label use approximately 500 watts.

Related Article: 250 Save Electricity Slogans

To find out how much electricity your home appliances use, you can use the following methods:

  • By reviewing Energy Guide label on your device. It will provide you with an estimate of the energy consumption in average and the cost of operation for the specific model. You should know that not all home electronics and appliances must have an Energy Guide.
  • By using a special device (Kill A Watt meter) designed to measure any appliance power consumption.
  • Using the basic formulas (provided below) to get the real power consumption of your device.
  • By having an energy monitoring system installed in your home.

Now that you’re familiar with the methods that you can use to calculate power consumption, let’s get acquainted with some basic things you also need to know.

Basic Units Of Every Power Consumption Appliance

Power consumption of home appliances

Here are the three main terms that you need to understand before you start calculating the power consumption of any appliance:

  1. Watts: Term Watts is used to rate the power of the appliance. For example, some household appliance like microwave has around 500 watts. This gives us a measure of how much electricity this device will consume in one hour.
  2. Operational Hours: This term defines how long (number of hours) a device operates. If you want to, for example, measure how much power your ceiling fan is consuming during five hours, those five hours are ‘operational hours’.
  3. Kilowatt-Hours: Kilowatt hours (kWh) represent the unit of power. This unit is used to calculate how much electricity some device consumes during its operation. kWh are then multiplied by the average price (depending on the country) of electricity.

While it is not difficult to determine the operating hours, sometimes it can be complicated to estimate the appliance wattage. In the next section, we’ll explain more about that.

For those who have garage doors openers at home, be sure to read How Much Power (kWh) Does a Garage Door Opener Use?

Reading the Wattage On The Label of The Device

Label on the bottom of some electrical appliance

Almost every electrical appliance comes with a label on the bottom where you can see its technical specifications. You can also find appliance wattage on that label among these technical data. If there is no label on your device, just go on Google and search for the same model that you have. You will find wattage in the product description. A good solution is to look for wattage on the device manufacturer’s website.

Calculating The Power Consumption of An Appliance

Calculate the power consumption of some home device

To calculate some devices’ power consumption, you need to know their wattage and operational hours. Here is the formula that we use for this:

P (kWh) = W (Watts) x t (Operational hours)

Let’s take a look at a few examples,

Example 1: A 200 Watt LCD TV is running for 24 hours for the entire month. Let’s see how much power it will consume.

  • Watts: 200 W
  • Operational Hours (t): 24 X 30 = 720 hours/month

Total power consumption of LCD TV: 720 Hours x 200 Watt = 144,000 Watt-hours = 144 kWh

Note! 1 kWh = 1,000 watt hours

Example 2: A 1000 Watt AC unit runs 2 hours per day for the entire month. Here’s how much it will consume.

  • Watts: 1000 W
  • Operational Hours (t): 2 X 30 = 60 hours/month

Total power consumption of AC unit: = 60 Hours x 1000 Watt = 60,000 Watt hours = 60 kWh

Note! When you calculate the power consumption of ACs, refrigerators, or other appliances that have a compressor, the value will be much higher than the real value. We will talk about this more later in this post.

Now that you learned how to calculate power consumption for any electrical device, let’s see how you can also calculate your electricity bill.

How To Calculate The Electrical Consumption?

To calculate the total energy consumption (kWh) of some electrical device, you have to multiply the operational hours of the unit by the appliance wattage (W or kW) and its electricity price ($/kWh).

For example, if you use a computer that consumes 300W for 3 hours, you’re consuming 900 Wh or 0.9 kWh per day. If we take that the average price of electricity per 1 kWh is 11 cents, you’ll consume (0.9 kWh x 30 days x 0.11 $/kWh) = $2.97.

How To Calculate The Electricity Bill For Using Some Device?

Calculate The Electricity Bill For Using Some Device

To calculate how much you will need to pay for using some electrical device (appliance), you must multiply its total power consumption with the electricity price for your area (state).

Electricity Bill ($) = Total Power (kWh) x price per kWh ($/kWh)

Electricity pricing – is the amount that your electricity provider will charge you for 1 kWh. The average price of electricity in the United States is around 11 cents per 1 kWh. You can easily find electricity pricing for the area where you live by dividing the monthly electricity bill you get by the power consumption per month.

If we take one of the examples above that we calculated, we can see the following:

Total electricity bill for running an AC unit:  60 kWh x 0.11 $/kWh = $6.6
(This is how much it will cost you to run the AC unit for an entire month for 1 hour per day)

If you want to use a simple way to calculate the electricity usage of any home appliance, then feel free to check this FREE Energy Use Calculator.

Exception To Some Electrical Appliances

Energy consumption of some electrical appliances

As mentioned earlier, some home appliances come with a compressor, and the calculation cannot be applied the same as with devices that do not have a compressor.

For example, let’s look at how a standard AC unit works. The compressor inside the AC unit is not always turned ON, and when it does run, it does not always run at the same speed. Because of that, the power consumption is not always the same.

To calculate the consumption of 1 Ton AC (which is approximately 800 watts) that runs on average 5 hours a day for a whole month, we use the following formula:

Monthly consumption of AC = 800 watts x 150 hours = 120 kWh.

However, the real power consumption is much lower than this. Most home appliances are Energy Star rated and come with a label that provides the user with information about the device, including annual power consumption.

The annual power consumption can also be calculated based on 1600 hours and standard operating conditions. Therefore the values you will get vary depending on the number of hours the appliance is used and its operating conditions. Keep in mind that the values will be a bit higher in real life for the same number of operational hours. But, if you need to calculate exact power consumption, you can do that too.

Home Energy Monitoring System

Home Energy Monitoring System

If you want to have complete control over the entire power consumption in your home, then we recommend installing an energy monitoring system. The features of whole-house energy monitoring systems vary, and their complexity and cost depend on the number of electrical circuits you wish to monitor.

The monitors are usually installed directly in the home’s main breaker panel, and this is usually done by a professional electrician. For this system to work properly, it must be connected to the home’s wireless network. That way, you can easily see and monitor all the data on your smartphone or tablet.

By having energy monitoring systems in your home, you can easily understand how and at what time your household appliances consume the most energy, which can help you to develop a strategy for saving money on electricity bills.

Measure Power Consumption By Using Kill A Watt Meter

Measure power consumption of any electrical device

The most accurate and easiest way to measure the power consumption of any electrical device or appliance is by using a Kill A Watt Meter. To use the device, just plug it into the outlet and then connect your home appliance to it (microwave, TV, gaming console, etc.), and it will show how much energy your appliance consumed.

> Buy Kill A Watt Meter HERE <

This device can easily be found on Amazon or some other online store. For appliances with compressors, like refrigerators or ACs, we advise you to measure these devices between 3 to 7 days. It is the only way to get exact power consumption. Here is a simple video that explains how to use this device.

If you want to know more about this topic, feel free to read How Much Power (Watts) Does a Mixer Grinder Use?

FAQ: People Also Ask

How do you calculate power in watts?

To calculate power in watts you use the simple formula P(W) = I (A) x U(V).  Let’s take a look at an example. When the voltage is 110V and the current is 3A, you must multiply 110 by 3 and you will get the power of 330 watts.

How do you calculate power in a circuit?

For every circuit element, the power can be calculated as equal to the voltage difference through the element, multiplied by the amount of current. By using Ohm’s Law we have V = IR, and therefore for resistors, we can apply additional forms of the formula for electric power. 

Final Thoughts

Calculating the power consumption of some devices is not a complicated task at all. Most of our home appliances have labels on the bottom that show how much power they consume. We also mentioned that if you don’t want to burden yourself with calculations, you can use energy measuring devices like the Kill A Watt meter that you can find in almost every electric shop. I hope this article has helped you learn something new.

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