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Do Smart Plugs Save Energy? The Honest Answer and How to Work It Out
Updated October 2026 · Meteor Electrical guides · 10 min read
Quick answer: Yes, smart plugs can save energy, but only by switching off things that would otherwise waste power: devices on standby, and appliances left on by mistake or longer than needed. The plug itself uses about 0.5 to 1W all the time, so the saving is real on groups of devices or higher-standby kit, but small, or even negative, on a single low-standby device.
Smart plugs are often sold as a way to cut energy bills. The honest answer to “do smart plugs save energy?” is that they can, but how much depends on what you plug into them and how you use them. This guide explains where the savings come from, how much the plug itself uses, and a simple method to work out your own saving. If you are new to smart plugs, start with our explainer what is a smart plug?.
In this guide
How do smart plugs save energy?
A smart plug does not make an appliance more efficient. It saves energy in three ways, all by making sure power is only used when it is needed:
- Cutting standby power. Many devices keep drawing power when “off”, to run clocks, lights, network connections or instant-on features. Switching the plug off removes that draw completely.
- Schedules and timers. Lamps, chargers and equipment switch off automatically overnight or while you are out, instead of relying on someone remembering.
- Remote control. If you leave something on, you can switch it off from your phone rather than leave it running until you get home.
There is also an indirect saving. A plug with energy monitoring shows what each appliance really uses, which often changes how people use it.
What is standby power?
Standby power, sometimes called vampire or phantom power, is the electricity a device uses while it is not doing its main job. Ecodesign rules limit standby use for many new products to low levels, often 0.5 to 1W. Older equipment, set-top boxes, games consoles in instant-on modes and some audio gear can draw several watts each, and several devices together add up.
How much electricity does a smart plug use?
A smart plug has to stay powered to listen for commands, so it uses a small amount of electricity all day, every day, whether the appliance is on or off. For most plugs this is about 0.5 to 1W.
That sounds tiny, but a plug runs for 8,760 hours a year:
- At 0.5W: 0.5 × 8,760 ÷ 1,000 = about 4.4 kWh a year.
- At 1W: 1 × 8,760 ÷ 1,000 = about 8.8 kWh a year.
So a smart plug only saves energy overall when the standby power it cuts is greater than its own consumption. Check the standby figure in the manufacturer's specifications if it is listed.
Pro tip: One smart plug feeding an extension lead with several devices saves more than one plug per device, because you pay for the plug's own consumption only once. Keep the total load within the plug's and the lead's rating.
How do you work out how much a smart plug will save?
You do not need a tariff table to estimate your saving. Work it out in kWh first, then apply the unit rate shown on your own electricity bill.
- Measure the standby power of the device or group in watts. An energy monitoring smart plug or a plug-in energy meter will show it.
- Decide how many hours a day the plug will switch it off, for example overnight and while you are at work.
- Work out the standby saved per year: standby watts × hours off per day × 365 ÷ 1,000 = kWh.
- Work out the plug's own use: the plug's watts × 8,760 ÷ 1,000 = kWh. Use 0.5 to 1W if the exact figure is not given.
- Subtract the plug's use from the standby saved to get your net kWh saving.
- Multiply the net kWh by your unit rate (pence per kWh) to get the yearly saving in money.
For appliances left on by mistake, such as a lamp or fan, add the running power you avoid: running watts × hours avoided ÷ 1,000. This can be much larger than the standby saving.
Worked examples: when do smart plugs save energy?
These examples use the method above with illustrative figures. Measure your own devices, as real standby power varies widely between models.
| Example | Standby draw | Hours off per day | Standby saved per year | Plug's own use per year (at 1W) | Net result |
|---|---|---|---|---|---|
| TV, soundbar, console and set-top box on one plug | 10W combined | 16 | 58.4 kWh | 8.8 kWh | About 49.6 kWh saved |
| Home office: monitor, printer, speakers | 5W combined | 16 | 29.2 kWh | 8.8 kWh | About 20.4 kWh saved |
| Single modern device | 0.5W | 16 | 2.9 kWh | 8.8 kWh | About 5.8 kWh lost |
The pattern is clear. A smart plug on a group of devices, or on older equipment with higher standby use, gives a worthwhile saving. A smart plug on a single modern device with very low standby can use more energy than it saves.
Where do smart plugs save the most energy?
| Good candidates | Poor or unsuitable candidates |
|---|---|
| TV and entertainment groups on one extension lead | Fridges and freezers (must stay on) |
| Games consoles in an “instant-on” standby mode | A single modern device with very low standby use |
| Home office kit: monitors, speakers, docking stations | Wi-Fi routers and alarm systems you rely on |
| Lamps and decorative lights that get left on | Set-top boxes that need standby to record or update |
| Chargers and power supplies left plugged in | Portable heaters, unless the manual allows timers |
Entertainment setups
A TV, soundbar, games console and streaming box often sit on one extension lead. Putting that lead on a smart plug and scheduling it off overnight is usually the biggest single standby saving. Let consoles and set-top boxes stay on standby at times they download updates or record.
Home office equipment
Monitors, speakers, printers and docking stations often stay on standby all evening and weekend. One schedule can switch them all off. Some printers run an ink-cleaning cycle after a hard power cut, so check before you include one.
Lighting
Lamps and decorative lights left on for hours waste far more than any standby draw. A schedule or an away mode stops that. For the lamps themselves, LEDs use much less power; see our guide to energy saving light bulbs or browse smart lighting.
Safety: Do not put fridges, freezers, medical equipment or alarm systems on a smart plug schedule. Only use a smart plug with a portable heater if the heater's instructions allow timer or remote control and the plug is rated for the full load, as many heater manuals forbid it. A smart heater with built-in controls is a safer way to schedule heating.
How do you use smart plug schedules to save energy?
Schedules save energy without you having to think about it. A few simple ones cover most homes:
- Overnight off: switch entertainment and office equipment off from late evening until morning.
- Workday off: switch equipment off while the house is empty.
- Countdown timers: turn chargers, fans or lamps off after a set time.
- Seasonal lights: run decorative lights in the evening only, using an outdoor-rated product such as a smart IP66 outdoor socket outside.
- Away mode: keep lamps on only at set times while you are away, rather than all day.
Review the energy readings after a few weeks. If a device uses less than you expected on standby, its plug may be better used elsewhere. Our energy saving tips for home and office have more ideas.
How do you choose a smart plug to save energy?
- Energy monitoring: the most useful feature for saving energy, as it measures what each device actually uses.
- Low self-consumption: look for a low standby figure in the specifications.
- Load rating: a UK plug-in smart plug is limited to 13A (about 3kW); some are rated lower, so check the label.
- Compatibility: make sure it works with your app or system, such as Alexa, Google Home or a Matter hub.
- Indoor or outdoor: outdoors, use a product with a suitable IP rating.
- One plug for many devices: a smart extension lead can switch several outlets from one device.
The Knightsbridge smart plug offers app control, schedules, energy monitoring and Alexa and Google Assistant compatibility. The Energy Saving Trust also has independent advice on reducing standby and home energy use.
Key takeaways
- Smart plugs save energy by cutting standby power, running schedules and letting you switch things off remotely.
- The plug itself uses about 0.5 to 1W all the time, roughly 4.4 to 8.8 kWh a year.
- Work out your saving in kWh: standby watts × hours off × 365 ÷ 1,000, minus the plug's own use, then apply your unit rate.
- Savings are best on groups of devices and higher-standby equipment, and can be negative on a single low-standby device.
- Keep fridges, freezers and medical equipment off smart plugs, and only use them with heaters if both allow it.
So, do smart plugs save energy?
Yes, smart plugs save energy when they switch off devices that would otherwise waste power, and the best results come from groups of devices and appliances that get left on. They are not magic: the plug has its own small draw, so measure first, put plugs where they cut the most, and work out your saving with your own unit rate.
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FAQs
Do smart plugs save energy?
Yes, when they are used to switch off devices that would otherwise sit on standby or be left running. The saving comes from cutting that wasted power, not from the plug itself. Because each smart plug uses about 0.5 to 1W, it only pays off on devices or groups with a meaningful standby draw.
How much electricity does a smart plug use?
A typical smart plug uses about 0.5 to 1W all the time it is plugged in, to keep its radio and electronics running. Over a year that is roughly 4.4 to 8.8 kWh. Check the standby figure in the manufacturer's specification for the exact plug you are considering.
Can a smart plug use more energy than it saves?
Yes. If you put a smart plug on a single device that only draws around 0.5W on standby, the plug can use as much or more than it saves. Smart plugs make most sense on groups of devices, older equipment with higher standby use, or appliances often left on by mistake.
How do I calculate how much a smart plug will save?
Measure the standby watts of the device, multiply by the hours a day it will be switched off and by 365, then divide by 1,000 to get kWh. Subtract the plug's own yearly use, then multiply the result by the unit rate on your electricity bill.
Which appliances are best to put on a smart plug to save energy?
The best candidates are TV and entertainment setups, games consoles, home office equipment, chargers and lamps that get left on. Avoid fridges and freezers, which must stay on, and only use a smart plug with a heater if both the heater and the plug allow it.
Is it worth turning off appliances at the wall?
It is worth it for devices with noticeable standby use, especially groups of devices. Many modern appliances have low standby power, so the saving from one device is small. An energy monitoring smart plug lets you measure the real figure before you decide.