What Is The Difference Between Volts, Amps and Watts?

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Written by Tristan Cameron

Volts, amps and watts are different ways we can measure electricity. The three serve different, yes necessary purposes, and at North Shore Electricians, we rely on all of them to help us diagnose and solve issues.

If we had to explain the difference in one sentence, volts measure the pressure, amps measure the flow of electricity, and watts measure the amount of energy used by multiplying the two.

But why is this important, and why do you need to know it? Understanding how the terms refer to your energy usage can help you to identify electricity excesses and save money.  

Let’s break it down individually.

What are Volts?

Volts is the base unit of voltage and is a measurement of the potential difference between two points. It’s the amount of electrical pressure inside a circuit. As the volts increase, so does the current. 

One volt is the difference in energy between two different points within a circuit or wire.

Energy providers in Sydney deliver energy to homes at two different pressure levels (voltages), 120V and 240V. The reason for this is that the bigger, more energy-guzzling appliances like air conditioners, washers and dryers need 240V, while your everyday items like light bulbs, laptops, and TVs only need 120V.

Here are some examples of levels of volts in particular objects:

ObjectVolts (V)
Rechargeable battery1.2
Non-rechargeable battery1.5
Car battery12
Electric vehicle battery400–800
Sydney Light Rail600–750
Overhead power lines380,000

The name volts is a nod to Italian physicist Alessandro Volta, who invented one of the world’s first batteries back in 1800.

What are Amps?

An amp (short for amperage) measures the flow of electricity through the circuit or the number of electrons moving through a wire. 

The switchboard is a common place in a home to see where amps are seen. The different circuit breakers will be listed, usually with 15, 20, or 30 amps. The larger the amperage, the more electricity flows through that circuit. 

The lower amperage circuits power most household devices, while the larger ones need 30 amps. If too much electricity is drawn from any of the circuits, the breaker kicks in, cutting off the flow and averting a short circuit or worse. 

The word amperage is named after French physicist André-Marie Ampère.

What are Watts?

Watts is the most commonly used term when it comes to talking about electricity. Lightbulbs, for example, come in a range of watts from 40W up. Pretty much everyone knows that the higher the wattage, the brighter the light. But why?

Watts is the amount of power a device needs to operate and is calculated by multiplying the volts by the amps. Think of watts as the power required to make something happen. Even making a doorbell ring requires at least 2W while operating a vacuum cleaner needs up to 900W.

The formula is W = A x V. 

So, as an example, 2A x 150V = 300W. 

Here’s the average amount of watts standard devices use:

DeviceAverage watts consumed
Light bulb60W
Hair dryer1200W
Clothes dryer4000W
Central air conditioning15,000W

Watts is named after the steam engine designer, Scottish Engineer James Watt.

What are Ohms?

We’re not done yet. There’s one more electricity term that gets thrown into the mix, and that’s the ohm. 

In most homes, wires are a combination of copper and aluminium; both have a natural resistance to friction, which means they can slow down the flow of electricity. Most devices also provide some level of resistance to the flow of energy.

This resistance is measured in ohms, named after Georg Simon Ohm, a German physicist and mathematician.

Why is all This Important?

Everybody wants to reduce their electricity bill. By understanding what watts means, you can make savvier decisions when choosing what appliances and devices to buy.

The higher the wattage, the more electricity is being consumed, and your energy bill goes up.

Today, most of the energy-guzzling devices we mentioned earlier come with an energy-efficient rating. The higher the star, the fewer watts they need to operate, meaning they’ll use less electricity. 

Many people in Sydney are choosing to switch to solar panels. Knowing your amps, volts, and watts is vital to determining how many panels to have installed. 

Understand the Terms and Save Money

With just a bit more than a basic understanding of the terms volts, amps, watts and ohms, you can know more about how the devices in your home consume electricity.

Does your home have enough energy-efficient light bulbs and other devices? Are the circuit breakers in your switchboard capable of handling the loads your devices need?

It’s time to contact North Shore Electricians so we can do an electrical inspection of your property. We’ll guide you on how to improve the flow of electricity to your devices and, in the long term, how to save money. Call us today.

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