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Smart plugs that show what your appliances cost
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A smart meter tells you what the whole house is using. It does not tell you that the old fridge in the garage, a tumble dryer, or a set-top box left on standby is the thing running up the bill. An energy-monitoring smart plug sits between the wall and one appliance and shows, in the maker's app, how many kilowatt-hours that appliance has used, and what that comes to at a unit rate you type in.
The plugs below are UK three-pin models with a built-in power meter. We have used Amazon UK prices checked today, with our Associates tag on the links. If you would rather see the whole house at once, start with our electricity monitors and smart meter displays guide, and with the energy price cap guide for the unit rate behind the sums.
Why a plug-in meter helps
The usual surprises are not mysterious “phantom loads” of a watt or two. They are things you can see and unplug: a portable heater, a tumble dryer, an older fridge-freezer, or a gadget that never really switches off. A monitoring plug lets you test one of those at a time for a few days, then move it to the next suspect. You do not need a hub, but you do need a 2.4GHz Wi-Fi network and a smartphone app.
What common appliances cost at 26.32p per kWh
These are labelled sums, not a promise. We have used Ofgem's GB average electricity cap unit rate for 1 October to 31 December 2026, which is 26.32p per kWh. Your own unit rate will differ, especially on a time-of-use tariff. Standing charges are the same either way, so they are left out. Always check the wattage on your own appliance.
| What is running | Assumption used | Cost |
|---|---|---|
| A 2kW portable heater | 2,000W for 1 hour | 2 × 26.32p = 52.6p an hour, or about £1.58 for 3 hours |
| A 2.5kW tumble dryer | 2,500W for 1 hour | 2.5 × 26.32p = 65.8p an hour |
| A 3kW kettle | 3,000W for 3 minutes | 3 × 0.05 × 26.32p = 3.9p a boil |
| A washing machine cycle | 1 kWh, a typical mid-range cycle (yours may be more or less) | 26.3p a cycle |
| An always-on 40W box (an old router, hub or set-top box) | 40W, 24 hours a day | 0.04 × 26.32p × 24 = 25.3p a day, or about £92 a year |
| A 10W charger or small gadget left plugged in | 10W, 24 hours a day | 6.3p a day, or about £23 a year |
A 2kW heater for three hours in the evening is the same sort of money as running a 40W always-on box for a fortnight. That is why it is worth measuring the actual thing in your house, rather than guessing. For warming one person instead of a whole room, a heated throw or underblanket uses far less than a portable heater; we compare those in Beat the cold for less.
How to use an energy-monitoring plug
- Set the plug up on 2.4GHz Wi-Fi in the maker's app, then type in your unit rate. Use 26.32p if you are on a standard variable tariff at the cap, or your own rate if you know it.
- Plug in one appliance only. Leave it for a normal day or two, including any standby time, then read the kWh and the cost in the app.
- Move the same plug to the next suspect. A single cheap plug is enough to survey a house; a two-pack lets you watch two things at once.
- Use the schedule or auto-off features if you want a dryer, heater or charger to stop after a set time. Do not use a plug to control a medical device, or anything that would be unsafe if it switched off unexpectedly.
- Stay inside the rating. The Tapo and Meross models below are listed at 13A, which is 2,990W on a 230V UK socket. A big portable heater can sit on that limit, so check the appliance rating first.
Plugs we checked today
All four were in stock on Amazon UK when we opened the pages on 15 November 2026. The Tapo P110 two-pack is the clear value option if you only want energy monitoring in the Tapo app. The Matter models are useful if you already use Apple Home, Alexa or Google Home as a hub.
Amazon UK
TP-Link Tapo P110 energy-monitoring smart plug, 2-pack
£14.24
Two UK plugs with energy monitoring, schedules, auto-off and away mode, rated at 13A / 2,990W. Works with Alexa and Google Assistant, no hub required, indoor use, 2.4GHz Wi-Fi. This was the cheapest way we found today to get two monitoring plugs, at about £7.12 each. The page is specifically the 2-pack; do not mix it up with a single-plug listing.
Price checked 15 November 2026
Amazon UK
Tapo P110M Matter energy-monitoring smart plug
£8.99 the page also showed £16.99
A single Matter-certified Tapo plug with energy monitoring, schedules and auto-off, for indoor use. You can set it up in the Tapo app without a hub. To use it in Apple Home, Alexa or Google Home you need a Matter-compatible hub. Tapo says energy monitoring is fullest in the Tapo app. In stock at £8.99 when we checked; the same page also showed a higher comparison price of £16.99. A good extra single plug if you already have the two-pack, or if you want Matter.
Price checked 15 November 2026
Amazon UK
TP-Link Tapo P115 mini energy-monitoring smart plug
£28.16
The compact nano Tapo plug, designed to sit closer to the wall so it is less likely to block a neighbouring socket. It has the same sort of energy monitoring, schedules and Alexa / Google voice control as the P110, with no hub required. It is in stock, but at £28.16 for one plug it is much dearer than the P110 two-pack. Only worth a look if you specifically need the smaller body.
Price checked 15 November 2026
Amazon UK
Meross MSS315 Matter smart plug with energy monitoring, 2-pack
£29.99
Two compact 13A Matter plugs with energy monitoring in the Meross app, plus Apple HomeKit, Alexa, Google Home, SmartThings and Home Assistant. A 2.4GHz network is required. For some Matter set-ups Meross also asks for a compatible hub, such as a HomePod mini or a recent Echo. About £15 a plug, so dearer than the Tapo two-pack, but a better fit if you want HomeKit or Matter as well as the energy figures.
Price checked 15 November 2026
A few practical notes
- These plugs need Wi-Fi. They will not record usage if they cannot reach the app, so test the signal at the socket before you rely on the figures.
- Indoor use only, and not for wet rooms unless the maker says otherwise.
- Energy figures in an app are a guide. They can differ a little from your bill, which is what you actually pay.
- If the problem is a draughty door or an unused chimney, a plug will not fix it. See draught-proofing on a budget.
All prices were read from Amazon UK's own product page on 15 November 2026. Prices can change, stock can run out, and delivery charges may apply. Amazon links include our Associates tag. This is not a recommendation to buy any particular product, and it is not safety advice: read the manufacturer's instructions. Stay within the 13A rating.
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