AMPs, Watts, and Volts: A Guide to Measuring Power

Understanding Energy MeasurementsYou are probably reading this article from an electronic device. By definition, that means you are using electricity to view it. It could be electrical power from the grid or just a rechargeable battery connected to your computer or phone. If you are using power from the grid, the electricity gets to your device in alternating current, commonly referred to as AC. However, if it comes from a rechargeable battery, then your device is getting power in the form of direct current or DC. While you have probably come across these terms in your daily power usage, most people don’t really understand what they mean.

You use energy for different purposes in your daily routines. These uses include lighting, running industrial machines, getting entertainment, learning, etc. Periodically, your power company sends you invoices for the power you’ve consumed. This is when having a better understanding of energy measurement comes in handy.

In this article, we’ll be looking at the various units used to measure energy output and power consumption. We’ll include a very basic breakdown of the meaning of the units used in this process. The main units of measurement are amperes, watts and volts. You might come across these terms on labels for batteries, power sources, schematics for devices, product descriptions and other places. The following is a basic but detailed explanation of these different measurements.


You might have heard the power company refer to power in units called watts. So, what is a watt? It is a designation used to measure energy. In simple terms, it is a unit that will tell you about the amount of power that an appliance uses when running on electricity. Most electrical appliance manufacturers will put this figure on the packaging of the appliance. If it is not on the packaging, you can look for it in the equipment manual.

For instance, a bulb labeled 25 watts pulls out 25 watts from your power line when you turn it on. The amount of energy used is also measured in reference to other factors such as time. For instance, we can have watt-hours and kilowatt-hours. A watt-hour is a measure of how much electricity an electrical appliance consumes in a given time. The timeframe designation is usually an hour.

For example, you may expect an appliance labeled 300-watt to consume about that amount of electricity if left on for an hour. Similarly, a kilowatt-hour (kWh) is a symbol that you might be very familiar with. This is the figure that your power company utilizes for its billing. Your bill will use this unit to indicate the total amount of energy that all your appliances have been using. A kilowatt represents 1,000 watts. Therefore, a kilowatt-hour is a composite unit equal to 1,000 watts of power sustained for an hour. Appliances like dishwashers consume an average of 500 kWh a year. A megawatt, on the other hand, is the equivalent of 1,000 kilowatts or a million watts. You use this kind of wattage to power large enterprises like factories or cities.


The term “amperage” is used to define the strength of an electric current. To better understand how all this works, you also need to know about voltage. We will discuss voltage as the pressure in a well of electricity that runs in your home. Therefore, we can discuss the ampere as the electrical current unit required by an appliance to run. From a general point of view, larger appliances will consume larger amperage.

Therefore, as stated above, an amp is just a measurement for the current used by a particular device. Devices with larger amp ratings work faster and better. However, this will cost you more in terms of electricity. To reduce your electrical bills, you will want to re-evaluate your appliances and find out which ones you can eliminate. For a similar result, you can also consider using appliances with lower current ratings.

When physically shocked by electricity, the amount of current is the factor that determines how dangerous the event is. Since you do not know for sure how much current is carried by one, you should certainly try to keep away from naked power sources. The worst-case scenario is electrocution.


We have just discussed the ampere as a unit used to measure the amount of current that a particular device needs to function. For the current to get to the required destination, it needs some transportation unit. Therefore, voltage is the measurement for the force needed to drive an ampere of current against the resistance of the material used. To put it simply, voltage is a measure of the pressure of electricity.

As a rule of thumb, the voltage always has to be constant. Voltages that are too high will result in your devices getting overloaded on connection. If you see the lights in your house dim out, this is usually due to inadequate voltage to push the current into the bulbs.

Most electrical installations come with a circuit breaker. They allow certain amounts of current to get into your home to power your household devices. If the current goes above the particular amperage rated for the circuit breaker, the breaker shuts down the current flow. This is vital for protecting your devices and home wiring.

How Electricity Gets to Your Home

Electric service comes to your home from the utility grid through two 120-volt wires that provide a combined power of 240 volts. Electrical power reaches your house through a mast and overhead main service cables (or, in some cases, underground cables). On the way, it passes through an electricity meter that records your overall usage. As soon as it enters your house, the initial stop for electrical power is your service panel.

How Is Your Home’s Amperage Determined?

The size of the power supply in your home determines the number of devices you can use simultaneously. A 200-amp power supply will allow you to use multiple appliances simultaneously. However, 60 amps may not provide enough power to run an electric water heater, cooking range and hairdryer at the same time. To measure your electrical service, explore your home’s electrical supply system’s major components — the cable, conduit, meter, panel and main circuit breaker — to determine which has the least amperage. The lowest rating will be the overall rating of your home’s power supply.

More Information on the Measurements

As you have read, understanding how much power your appliances use is important. If you own a home or commercial property in Frederick, Maryland, you can contact Wenbrooke Services for more information. We offer excellent electrical, cooling, and heating services throughout the Greater Frederick County area. We have the background and training to understand how watts, amps and volts work together to give your home enough power.

At Wenbrooke Services, we also offer services related to rewiring, generators, maintenance plans and emergency breakdowns. In fact, we provide a complete line of electrical and solar services. You can even contact us if you need heating and cooling services such as repair, maintenance or installation. Our experts are highly trained to furnish dependable advice and assistance. To learn more about all the ways we can assist you, give us a call today.