Energy monitors: Plug-in energy monitors

Socket monitors, also known as plug-in energy monitors, allow you to measure the electricity usage of a single appliance. We haven’t tested plug-in energy monitors in our lab, but we’ve tried out three models to bring you our first impressions.

If you want to monitor the energy usage of your whole home then you’ll need a standard energy monitor (discover which are best in our energy monitors review).

However, if you just want to monitor the electricity usage of individual appliances then you might consider buying a plug-in energy monitor.

The three plug-in energy monitors we tried ranged from £10 to £25 and, while they all gave us the same readings in watts, the additional information they offered and how user-friendly they were varied from model to model.

The monitor that will best suit you depends on the type of information you want to see and how much money you are willing to spend.

Belkin Conserve Insight energy use monitor

Belkin Conserve Insight energy use monitor - £25

This was the most expensive plug-in energy monitor we tried and it was our favourite, thanks to its user-friendly design and clever features.

It is the only monitor we tried that has a display screen that is separate to the plug (attached by a cable). This makes it easier to read the screen as you do not have to bend down to look at the plug socket and it would be particularly useful if your plug socket is in an inconvenient place such as behind your fridge.

The instructions are clear and easy to follow and the display is easy to use and understand. It has just three buttons and displays your usage in terms of watts, pounds and carbon emissions. It’s easy to enter your electricity unit rate (you can find this on your energy bill) and doing this will give you a more accurate estimate of your costs.

We particularly liked the Belkin’s clever averaging function which, once an appliance has been plugged in for at least 45 minutes, will calculate estimated annual costs for the appliance – based on how you use it. It will continue to refine this estimate as long as it is plugged in.

One potential downside of this monitor is that it doesn’t supply as much additional information as the other two sockets in terms of extra measurements like voltage, current and power factor – but unless you specifically need this information, then we don’t think you’ll miss it.

Pros: Very user-friendly, easy to use and understand, clever averaging function.

Cons: Slightly more expensive than others, doesn’t give as much additional information.

Available from: Amazon, Currys, Dixons, PC World

Ecotek Energy Monitor

Ecotek energy monitor - £20

This is a more standard-looking plug-in energy monitor, with the screen situated on the plug itself. We found it fairly easy to use although its small dark screen was quite hard to read without bright light.

It offers a lot more information than the Belkin monitor above. As well as giving your real-time usage in watts and cumulative usage in kWh it also offers readings of current voltage (Volts), electric current (Amps), Current mains frequency (Hz), Instantaneous Volt Amperes and Power Factor.

If you need this level of detail then you may find this monitor suits your needs – however we think that for the average consumer who wants to identify power-guzzling appliances in order to cut down their electricity usage, a monitor that simply provides an appliances electricity usage in watts/kWh will probably be enough.

Like the Belkin, this energy monitor has an internal battery so will save your data (such as the electricity unit rate you’ve set) if it is unplugged.

Pros: Gives lots of detail.

Cons: Small dark screen can be hard to read.

Available from: Argos, Homebase, Amazon

Efergy Energy Monitoring Socket

Efergy Energy Monitoring socket - £10

This was the most basic of the three plug-in energy monitors we tried. When we unplugged it, it appeared to reset itself and so each time we plugged it in again we had to re-enter our tariff unit rate.

Like the Ecotek energy monitor it offers a lot of information (on top of real-time usage in watts and cumulative usage in kWh) including current voltage (Volts), electric current (Amps), Power Factor and current mains frequency (Hz) - but again you should think about whether you would use all this information before you consider it a benefit.

We found the instructions quite vague but were able to work out how to access the different readings. The monitor has a nice large screen which is easy to read (as long as the plug is in an accessible place)

NOTE: Since we tried out this Energy Monitoring socket, Efergy has launched a new improved version. The new model promises a new LCD screen with clearer and more extensive information (including cost by day and cost by year) and costs £20 from Efergy.com.

Pros: Cheap, offers lots of additional information.

Cons: Loses all data when unplugged.

Available from: Amazon

More on energy monitors

Which? works for you