Difference between Wattmeter and Energy Meter

The main difference between a wattmeter and an energy meter is that a wattmeter is employed to measure electrical power consumed in an electric circuit, whereas an energy meter is used to measure the total amount of electricity consumed by an electric load over a period of time.

Another major difference between a wattmeter and an energy meter is that a wattmeter gives a reading in watts (W), while an energy meter gives a reading in watt-hour (Wh).

Definition of Wattmeter

A wattmeter is an electrical measuring instrument used in electrical circuits to indicate the power consumed. It shows the reading in watts, kilowatts, etc. Wattmeter basically measures active power consumed by an electrical device. It provides information about the rate of work being done in an electric circuit.

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Definition of Energy Meter

An energy meter is an electrical measuring device used to record the amount of electrical energy consumed by a load device over a specific period of time. It shows readings in watt-hour or kilo-watt-hour. Energy meter is widely used in our homes to measure our monthly electricity consumption. It provides information about the total amount of work done in an electrical circuit over a period of time.

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Now, let us explore all the significant differences between a wattmeter and an energy meter in tabular form.

Difference between Energy Meter and Wattmeter

All the important differences between a wattmeter and an energy meter are given in the following table:

Key	Wattmeter	Energy Meter
Function	A wattmeter is used for power measurement in an electric circuit.	An energy meter is used for measuring total energy consumption in an electric circuit.
Unit of measurement	Wattmeter gives readings in watts or kW.	The energy meter gives readings in watt-hour or kWh.
Types	Wattmeters are of two types: induction-type wattmeter and electrodynamometer-type wattmeter.	Energy meters are of three types: disc-type energy meters, electronic energy meters, and smart energy meters.
Instrument category	Wattmeter is a type of indicating instrument.	An energy meter is a type of integrating instrument.
Formula behind operation	Wattmeter measures power which is given by, P = V I cosϕ	Energy meters measure electrical energy which is given by, W = P × t
Usecase	Wattmeter is used to indicate the power consumed by a device, the power rating of a device, etc.	An energy meter is used to record total electricity consumption by a load, for billing purposes, etc.

Hence, in this article, we have listed all the major differences between a wattmeter and an energy meter. From the above comparison, it is clear that the wattmeter and energy meter are two different instruments used for different purposes.