Are energy monitors the best way to measure your power usage?

With energy prices surging through 2022, we're all trying to find new ways to save money by cutting back on our power bills and consumption.

While smart meters are an excellent way to see how much power you might be using each day, it can still be difficult trying to figure out which of your electronics are using the most power. 

Luckily, plug-in energy monitors can make this arduous task more straightforward. 

What is a plug-in energy monitor?

Household devices are plugged into the plug-in energy monitor, which is then plugged into the wall socket to ascertain how much power is used. 

You can hook up and measure almost anything that uses electricity, as long as it has a three-pronged UK plug. This includes single devices such as a kettle, washing machine, or electric oven. Power monitors can also measure how much energy several different electronics use through a power strip, such as a TV and speaker setup or a desktop computer with multiple screens. 

Using an energy monitor is one of the best ways to clearly ascertain how much electricity you're using on individual appliances  —hopefully helping you to work out where money can be saved in the long run.

Alongside plug-in energy monitors, you can also find energy monitors that hook up directly to your home power supply, although these are generally more expensive and harder to set up. These kinds of energy monitors typically cost more than £60, require a wi-fi connection and a smartphone to operate. 

For this article, we're focusing solely on the kinds of energy monitors you can plug into an outlet. 

What is the difference between a smart meter and a plug-in energy monitor?

Both smart meters and energy monitors measure your electricity usage. 

Their difference is a matter of scope: energy monitors measure how much electricity one plug socket uses, while smart meters keep track of how much power an entire home uses per day, week, month, or year. 

Both devices can help you to see how much power you're using and how to reduce your energy consumption. 

Electricity suppliers are often required to provide you with a smart meter as a way of reporting your usage, so you don't need to submit manual readings for your bills. 

An energy monitor, on the other hand, is usually bought separately to measure power drawn from individual plug sockets and are for personal use.

Why should I consider getting an energy monitor?

While manufacturers and the team at Which? can calculate average running costs on certain appliances, the actual cost you pay depends on a multitude of other factors unique to your usage, your home and your energy contract. 

Getting your own readings using an energy monitor can provide a clearer picture of how much money you're spending when running your electronics and provide answers on where you could cut back.

Should I get a smart meter or an energy monitor?

It depends on what you're looking to do. If you want to keep track of how much total electricity your household uses, a smart meter is one of the easiest ways to do this. 

With a smart meter, you don't have to take manual meter readings and report them to your energy provider as the meter will do this automatically. 

You can still determine the energy usage of certain appliances by looking for spikes in your power consumption when you have electricity-hungry devices running, but this isn't always accurate.

If you're trying to figure out the energy usage of one appliance or power strip, a plug-in energy monitor might be best to use instead. 

Being able to get a reading directly from a plug socket can help you figure out which appliances are using the most power without having to do lots of guesswork or maths, as you would when trying to determine the same information with a smart meter. 

With energy monitors, you can get a more precise measurement of energy usage and cost per individual electronic device.

Want to learn more about smart meters? Read our guide on what a smart meter is and how to get one.

What energy monitor features should you look out for?

The best energy monitors aren't necessarily the ones with  bells and whistles. Most models are similar – in fact, some are the same model rebranded across different sellers. 

When buying, one of the most important features to consider is proper calibration, which will ensure your readings are correct. Energy monitors should be consistent with the manufacturer's own kilowatt-hour readings for various appliances. You should also be able to get consistent results when using other monitors side by side. 

Asides from proper calibration, two other useful features to have are a built-in display and being able to input your energy unit price directly into the monitor. Having these features ensures you to get a direct reading on how much something costs to run. This can save you from having to do more maths, always a plus.

Some smart plugs have energy monitoring capabilities, but they don't usually come with a built-in LCD screen. They require a smartphone and wi-fi connection to function, and are primarily used to turn things on and off remotely. 

What to avoid when buying an energy monitor

It's important to keep in mind that buying an energy monitor won't automatically reduce your bills – you'll have to do that yourself by finding and unplugging power-hungry electronics. 

Sellers that advertise a dramatic decrease in power bills by simply leaving a magic fix-all plugged in probably aren't being very honest. 

Wondering how else you can save money during 2023? Read our guide on 17 ways you can save on household and living costs.

How to use an energy monitor to measure your power usage

When measuring how much power something uses, there are usually two ways of doing so. 

You can measure an ongoing read on something that is always plugged in or turned on, such as a refrigerator, desktop computer or TV.

Alternatively, you can measure things that you only use intermittently, such as a kettle, washing machine, or a corded vacuum cleaner, each time you use them.

To get an ongoing read is easy: plug in your monitor to the outlet, then plug in the electronics or appliances you want to measure. Once you're ready to start measuring, set your unit price on the monitor, use what's plugged in as normal, and watch how quickly (or slowly) the display ticks up in either kilowatt-hours or total cost. 

If you want to find out how much something costs per use, plug in your appliance or electronics into the monitor and set your unit cost. Then use as normal (eg a single kettle boil), see the result in either kilowatt-hours or cost, then reset the monitor before your next read. After getting a few results, you can calculate the average cost from there. 

Getting readings this way can help you determine whether it's worth using something in longer, larger uses. It can also show you the difference in modes like a lower-temperature wash, eco or economy modes, and so on.

Resetting your monitor can be done by pressing the 'reset' button; some models require you to do this with a metal pin. 

If you want to measure how much energy multiple devices use, you just need to plug the monitor into your wall socket, plug in a loaded power strip to the monitor, set the unit cost and use as normal. Be sure to keep an eye on the speed at which the monitor ticks up to determine your energy consumption.

Measuring your power can help you cut down your energy bills and consumption, saving you money in the long term.

How much do energy monitors cost?

While you can find some cheap energy monitors for less than £10, we can't say they'd live up to our standards here at Which?. For as little as £18, you can find models for sale that come with all our recommended features – proper calibration that provides consistent readings, built-in display and the ability to input your energy unit price directly into it.

Find out the annual cost of each of your appliances and get tips on lowering your energy bills with our guide on average appliance costs.

The energy monitor Which? used in its tests

When we looked at how to measure the electricity used to run a certain appliance, the best energy monitor for our needs was one we purchased from RS Components for £27.38. 

While it is more expensive than the average energy monitor, we splurged on this one because RS Components has a good reputation for its monitors being well calibrated. 

Considering the amount of work we knew we'd be putting it through, such as figuring out how much it costs to leave your tech on standby, testing products such as the best electric heaters and the best electric blankets and throws, we knew its three-year warranty would come in handy.

What other energy monitors are available? 

The best energy monitors aren't always the most expensive models.

There are cheaper options available than the monitor we tested from RS Components. They include all the recommended features we've recommended you look out for and are widely available at the time of writing.

• Energenie Ener007, £17.99 from Screwfix: sporting all of our recommended features, it also comes with a one-year manufacturer's guarantee. 

The energy monitors from RS Components and Screwfix are the only two models that are not sold on Amazon. 

While there are hundreds of monitors for sale on Amazon, here are a few that have our recommended features.

• Yurayisen Electricity Usage Monitor, typically £14.99 from Amazon: this model has our recommended features, however, reviewers say that it does not come with instructions on how to use it. It doesn't come with a guarantee or warranty beyond Amazon's standard 30-day return window, either.
• Yagosodee Electricity Usage Monitor, typically £17.99 from Amazon: this monitor doesn't come with an LCD backlight, which might be preferable if you're trying to sleep in the same room. It doesn't come with a guarantee or warranty beyond Amazon's standard returns policy.
• Maxcio Dual Tariff Energy Monitor, typically £21.99 from Amazon: if your energy contract has dual peak and off-peak tariffs, this model can store and monitor both, so you don't have to manually switch your unit cost whenever you want readings for your off-peak tariff. Maxcio claims to offer a 1-2-year warranty depending on the product, but we could not verify that this monitor comes with one. 

If you'd prefer to shop in person, you can sometimes find plug-in energy monitors at your local hardware store.

Can I get a free energy monitor?

All British energy suppliers must aim to install a smart meter in every home as part of a government programme to replace older energy meters. 

Energy monitors, unfortunately, are not included in the programme, and you'll have to purchase one separately.

If you don't have a smart meter or aren't sure if you have one, you can learn more about the government's programme and request a smart meter through Ofgem.