kWh Metering Devices: Parts, Functions, & Operations

kilowatt measurement device

You may not enjoy paying your bills, but there’s no escaping such a responsibility. Letting those monthly payments slide will only lead to more trouble in the future. So at the very least, you’ll want to ensure that what you pay correctly reflects your energy usage, right? You can do so if you understand the process for computing the bill. 

In the case of your energy bill, there’s such a thing called kilowatt-hour metering that lets you know where the amount in your account comes from. A device measures the total kilowatt-hour consumption of your home, which becomes the basis of your bill’s computation. Learning to read the energy meter will help you verify if the amount you pay each billing period corresponds to your power usage. 

Here’s an in-depth discussion of kWh metering. 

What is Kilowatt Hour Metering?

The kilowatt-hour (kWh) is a unit of energy. It’s equivalent to one kilowatt of electricity consumed in one hour. For the power company to determine how much electricity you use, they need to measure the amount and give you an accounting of the details. This is where kWh metering comes in. 

Your energy bill is computed based on your home’s total energy usage (or kWhs) over a specified period, usually on a per-month basis. The kWh meter measures the consumed energy you’ll need to pay during the stated billing cycle.  

What is a Kilowatt Hour Meter?

Kilowatt-hour meters are one of the most commonly used types of energy meters. They are compact electronic monitoring devices that record the consumed energy flowing through the circuit and provide an accounting of the total energy used. The figures are expressed in kilowatt-hours and represent the sum of the power that has been used over a specified period.

By using kWh meters, consumers can monitor their energy consumption in real-time instead of waiting for their electricity bill. Revenue grade meters let power consumers verify bills for accuracy. 

The kWh meter is installed in conjunction with the circuit supplying electricity to the home, such as the main panel or distribution sub-panel.  

How Does it Work?

kWh meters work by measuring the electricity consumption flowing through a circuit, such as standard 120 or 240-volt lines. This consumption reflects the electricity drawn by all of your household appliances and devices. The meter also acts as a kWh calculator.


An aluminum disc is the primary part of a kWh energy meter. The disc is supported by a spindle with a worm gear, a device with a spiral thread that engages with a toothed wheel. The worm wheel drives the dials that record the circuit’s energy consumption.  

In addition to the aluminum disc, kilowatt hour meters also have coils. These coils work along with the disc and permanent magnet to measure the kWh used. 


Kilowatt-hour meters measure and calculate your home’s power usage in billing cycles. The energy consumption is measured in kilowatt-hours. The periodic readings the energy meters take become the basis of the utility companies’ computation of your home’s total usage and ultimately, the energy bill. 


One coil that’s attached to the aluminum disc produces a magnetic flux proportional to the input voltage. Another coil produces a magnetic change proportional to the current. A lag coil delays the influx of the voltage coil’s magnetic field, causing eddy currents to flow through the aluminum disc. The eddy currents apply force to the disc in direct proportion to the coil’s current and voltage. 

Meanwhile, the permanent magnet that forms part of the meter exerts an opposing force on the disc. The forces working on the disc produce a disc-speed rotation that’s proportional to the power generated. A registered device activated by the disc counts the number of times the disc spins to determine energy usage. 

Calculating your Energy Consumption

To calculate your home’s energy consumption, you’ll need to look for the imported energy or the energy used, as that’s the basis of your electric bill. The numbers displayed on your meter are in kilowatt-hours (kWh), which reflect the amount of electricity your home used for the specified period.

Calculating your Electric Bill

You may want to learn how to calculate your electric bill to plan your budget. This works well, especially if you’re renting and are under a kWh sub-metering scheme. The key to understanding your bill is determining how many kWhs you use. You can then easily estimate your bill based on the prevailing electricity rates in your area. 

Take note of the numbers of your sub-meter, reading them from left to right. Record the numbers and deduct last month’s kWhs reading from your current one. The difference is the amount of electricity you consumed for the month. 

Now that you know how much energy you use, determine the per kWh price of electricity in your area. Multiply the rate by the number of kWhs you consumed. This will give you an idea of the amount you’ll need to set aside for your incoming bill. You may not be able to accurately monitor your usage with this method, but it’s enough to give you a leg up on your budgeting chores. 

Applications of a Kilowatt Hour Meter

kWh metering projects range from landlords, homeowners, and small businesses up to large corporations and organizations. The kilowatt-hour meter figures are prominently in the following applications. 

Tenant Submetering

Using kilowatt-hour meters allows landlords or property managers to perform energy audits of their individual tenant’s power usage. Through submetering, each tenant is obliged to pay in proportion to their consumption. Knowing their energy use level can help renters reduce their overall usage. This translates into savings in overhead costs for the property owners. 

Energy Efficiency

Energy efficiency is based on understanding where energy is consumed and using the knowledge to make the necessary adjustments in power usage. In this regard, kWh meters are instrumental in auditing a home or building’s energy efficiency. 


What is Meant by 1 Kilowatt-Hour?

The kilowatt-hour (kWh) is a measure of energy. It relates to the amount of electricity expended for 1 hour and is used as the basis for computing the energy consumption of residential and commercial power users

How Can I Monitor my Home Electricity Usage?

You can monitor your home’s electricity usage by comparing your bills from one month to the next. However, that won’t tell you which areas of your home or which appliances consume the most electricity. Consider installing an electricity usage monitor to get specific details regarding your energy usage. Several models exist, but the simplest, a plug load monitor, connects into an outlet and displays the energy consumption of any appliance or device you plug into it. 

How is kWh Calculated in the Electricity Bill?

The kilowatt-hour rate is the price of the electricity supplied by your power provider. To get your kWh consumption, determine the number of watts all your appliances and devices consume. You can use an electricity usage monitor for this purpose or manually compute the consumption based on their wattages. The wattage is expressed in watts (W), which you need to convert into kilowatts (kW). You do so by dividing the number of W by 1,000. That will give you the consumption in kW. To get the kWh, multiply the kW by the number of hours you operate your electronics. 

How Many kWh Does a House Use Per Month?

Data from 2020 shows that a typical American home uses 10,715 kilowatt-hours (kWh) a year. That translates into an average of 893 kWh per month. With an average per kWh rate of 13.72 cents, residential users spend around $122.50 monthly for their electricity needs.  


Monitoring your power usage makes you aware of how much you spend on your electricity costs. Knowing which areas of your home contribute the most to your consumption can help you determine what behavior or lifestyle changes you’ll need to employ to cut your energy expenses. Knowing how to read your meter is the first step in gaining control over your utility expenditures. 

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