An energy monitor works alongside a smart meter and shows you how much energy you are using in real-time. It can tell you which appliances in your home use the most energy, and therefore which to use sparingly.

The monitor will show your electricity usage, and also your gas if you are on the main gas network.

If you don’t have a smart meter but still want to monitor your electricity use, you can buy a standalone energy monitor, but it will only monitor electricity. Click here for details.

If you have an energy monitor and are having problems with it, please see our page on Resolving issues with smart meters and in home displays.

Some suppliers encourage customers to use a phone app instead of providing an energy monitor. The advantages of an app are that you can view the data in ways that lead to better insights. It will show you patterns in your usage, view retrospectively the exact moments when your energy usage was as its highest and more easily monitor and compare different ways of using energy in your home. The disadvantage is that the app doesn’t show real time energy use and can take up to 24 hours to update.

If you want an in-home display and can’t get one from your supplier and don’t want to use their app, there are third-party apps available. Examples are Loop Energy and ivie.

Using an energy monitor

Monitors should be placed somewhere visible, such as the kitchen or sitting room, so that you can keep an eye on them.

You can set your energy monitor to display your energy consumption in pounds (£) or kilowatt hours (kWh), depending on what works for you.

To accurately know your usage in pounds you need to make sure the energy monitor is set to the correct price for your tariff. Your energy supplier can do this remotely. Your bill, online account or prepayment meter display will list your daily standing charge and price per kWh unit.

Energy monitors vary, but common features include:

• Viewing how much electricity and gas you are using at this moment, as well as how much you have used today or in the last week or month.
• Setting a daily electricity or gas usage target, giving you an energy ‘budget’ to aim for.
• If you have a smart pay-as-you-go meter, the display may show how much credit you have left.
• You may also be able to access your energy monitor display on your computer or smart phone, including viewing analysis charts.

Changing your habits

You may want to just use the monitor to predict your energy bills, but their main benefit is the greater control you gain from the information it provides, as you can assess your energy usage and work out ways to save money.

First off, see how much electricity your home uses ‘at rest’, that is, the amount used during the night or if everyone is out. This is often referred to as the ‘base load’. Turn off everything that doesn’t need to be on – all lights, TV, washing machine etc. If an appliance is on stand-by, switch it off at the wall socket.

Things that you can’t turn off are your fridge freezer, medical equipment, certain home-entertainment set-top boxes and so on. The total usage will be displayed on the monitor – this is your base load.

By turning appliances and devices on one by one, you’ll get a good idea of which use the most electricity. You will notice that some appliances use a lot but are on for a short amount of time (for example, a kettle), while others use less but are on for a long time (tumble driers, halogen lights etc). You can use this information to get an accurate idea of where the greatest savings can be made.

The best way to know if changes you are making to your energy use are working is through monitoring. Try different approaches for a period of time such as a week and see how your usage compares, using your smart meter in-home display. For example, changing your heating schedule or temperature, using a timer plug, or heating hot water every other day instead of every day. Bear in mind changes in weather and other factors.

Cost of a cuppa …

Here’s how to find out how much everyday appliances are costing you. First, select the screen of your energy monitor which shows your total usage for today in terms of pounds and pence. Make a note of the figure.

Next, boil the kettle or run the washing machine. When the appliance has finished working check your monitor again, and see how much the figure for what you’ve spent on electricity that day has gone up. This is what making a cup of tea or doing a load of washing has cost you.

Accuracy of in-home displays

In-home displays aren’t 100% accurate but are usually within a margin of about a few pence a day.

Depending on the supplier, some include VAT on the prices they display, while others don’t. And they do include the daily standing charge, but this is added all at once, just after midnight for electricity, but later in the day for gas. 

The unit rates on electricity should update every 10 seconds and gas every 30 minutes, but often your supplier hasn’t set your in-home display up to update this often.  If the unit rate is out of date, you can ask your supplier to send the command “Update Tariff Configuration” to your in-home display.  

Stand-alone energy monitors

Stand-alone energy monitor (i.e. one not connected to a smart meter) cost around £40 and are easy to install yourself. The monitor needs to be within about 10 metres of your electricity meter to work effectively. They comprise a sensor which clips onto the power cable of your electricity meter and a visual display unit, which this page covers. Note that if your home has solar PV, be aware that not all monitor clamps can tell the difference between in-coming and outgoing energy flow.

Smart plugs

If you don’t have an energy monitor, or would like to monitor some appliances in more detail, you could use a smart plug. Smart plugs often look similar to normal extension cables that are plugged into sockets at the wall, but they have the capability to control the appliances that are plugged into them remotely and monitor their energy consumption via an app on your smart phone. For more information on smart plugs, see our webpage.

Monitoring gas

If you have a smart gas meter you can use your energy monitor to assess how much things like your gas central heating or gas oven cost to run. However, it’s a bit more complicated than with an electricity energy monitor because the display isn’t updated in real time.

This is because the in-home display only gets updated every 30 minutes for gas which means that sometimes the in-home display will show that you’re using gas when you’re not – it’s still showing data from the last time it was updated.

Accessible in-home displays 

An ‘accessible’ in-home display has been developed in partnership with the Royal National Institute for the Blind and should be available through your supplier. It has all the features of a regular smart meter in-home display, with the addition of accessibility features which include: 

• Tactile buttons with feedback of button press 
• Text-to-speech function for screen navigation 
• Adjustable volume for the text-to-speech function 
• Coloured LEDs which indicate electricity usage 
• LED push button to replay speech 
• Large typeface 
• Screens optimised for visual impairment and colour blindness 

If you think that you need an accessible in-home display discuss it with your energy supplier. If they refuse to offer you one, or say they are unavailable, you may want to consider raising a complaint. See How do I make a complaint to my energy supplier 

Troubleshooting issues with in-home displays

If you are missing an in home display, or the one you have isn’t working, see our advice sheet on Resolving issues with smart meters and in home displays.