How Much Electricity Does a Smart Home Use?

Smart Home Electricity Use: Quick Answer

The electricity consumed by a smart home depends on the number and type of devices installed.

As an illustration, if all of the always-on smart-home equipment in a property averaged a combined:

Important: these are mathematical examples, not estimates of what every smart home consumes. Your actual consumption depends on your equipment and how it operates.

You can calculate your own figures using our free Smart Home Electricity Cost Calculator.

Why Smart Home Electricity Consumption Is Easy to Overlook

A 3-watt or 5-watt device sounds almost insignificant compared with an electric kettle, oven or tumble dryer.

The difference is operating time.

A 3,000-watt kettle may only operate for a few minutes. A 5-watt smart-home device could operate for 8,760 hours every year.

That means low-power devices can still make a measurable contribution to annual electricity consumption when they're never switched off.

And a smart home rarely contains just one connected device.

It might contain:

• Several smart speakers.
• Smart displays.
• Smart plugs.
• Smart bulbs.
• Motion and contact sensors.
• Security cameras.
• A video doorbell.
• Smart heating controls.
• One or more smart-home hubs.
• A Wi-Fi router and mesh nodes.
• A robot vacuum and charging dock.

Individually, many of these devices consume relatively little. Collectively, the always-on load becomes more interesting.

The Most Important Smart Home Electricity Number: 8,760

There are 8,760 hours in a standard 365-day year.

This gives us a useful shortcut for anything operating continuously.

A device drawing exactly 1 watt continuously uses:

1W × 8,760 hours = 8,760Wh

Divide by 1,000 to convert watt-hours into kilowatt-hours:

8,760Wh ÷ 1,000 = 8.76kWh per year

At an illustrative electricity rate of 25p per kWh:

8.76 × £0.25 = £2.19 per year

This means you can quickly estimate the cost of a continuous electrical load:

For your actual cost, replace 25p with the unit rate on your electricity tariff.

Which Smart Home Devices Use Electricity 24/7?

Many smart-home products need continuous power because they must remain available to receive commands, communicate with other devices or monitor the home.

Smart Speakers

Smart speakers such as Amazon Echo and Google Nest devices normally remain powered continuously so they can respond to voice commands and provide smart-home control.

Smart Displays

Smart displays perform many of the same functions but also power a screen. Their consumption can vary depending on screen brightness, activity and model.

Smart Home Hubs

Hubs are generally designed to remain switched on continuously because other smart-home devices depend on them.

See What Is a Smart Home Hub? for more information.

Smart Security Cameras

Mains-powered cameras may operate continuously, particularly when providing motion detection, recording or live-view functionality.

Video Doorbells

Wired video doorbells and associated hubs or base stations can contribute to the property's continuous load.

Smart Plugs

A smart plug requires some electricity for its electronics and wireless connection even when it has switched off the appliance connected to it.

Smart Bulbs

When a smart bulb is switched off through an app or voice assistant but still powered at the wall, its wireless electronics need a small amount of standby electricity so the bulb can receive the command to switch back on.

Network Equipment

Your router, mesh Wi-Fi system and network switches aren't necessarily smart-home gadgets themselves, but they provide the infrastructure on which many connected devices depend.

Do Battery-Powered Smart Sensors Use Much Electricity?

Battery-powered smart sensors are a different proposition.

Motion sensors, door/window sensors, temperature sensors and water-leak sensors can often operate for long periods from a small battery because they're designed for extremely low-power operation.

Protocols such as Zigbee and Thread are particularly suited to low-power smart-home devices.

That doesn't mean their energy use is literally zero, but they generally aren't the first devices we'd investigate when looking for significant mains electricity consumption.

For examples, see our Best Smart Sensors UK guide.

Example: A Small Smart Home

Consider a simple setup consisting of:

• One smart speaker.
• Four smart bulbs.
• Two smart plugs.
• Two battery-powered sensors.

The exact electricity consumption would depend on the products chosen and how they're used.

Rather than assigning generic wattage figures to those products, the most accurate approach is to obtain measured consumption for each mains-powered device.

You could then calculate:

Smart speaker consumption + smart bulb standby/operating consumption + smart plug consumption = smart-home electricity total.

Battery sensors could be treated separately because their energy comes from replaceable or rechargeable batteries rather than directly from the household electricity supply.

Example: A Larger Smart Home

A more advanced property might include:

• Three smart speakers.
• Two smart displays.
• Twenty smart bulbs.
• Eight smart plugs.
• Two smart-home hubs.
• Four security cameras.
• A video doorbell and base station.
• Smart thermostat and radiator controls.
• Several sensors.
• A robot vacuum dock.
• Three mesh Wi-Fi nodes.

Even if individual products have relatively modest consumption, the total number of devices means it's worth measuring the combined always-on load.

For example, a combined continuous load of 50 watts would consume:

50 × 24 × 365 ÷ 1,000 = 438 kWh per year.

At an illustrative 25p/kWh, that would cost:

£109.50 per year.

Again, 50 watts is an example rather than a claim about what the equipment above will consume.

How to Calculate Your Smart Home's Electricity Consumption

The basic calculation is:

Watts × hours used per day × days ÷ 1,000 = kWh

Then:

kWh × electricity price per kWh = running cost

For example, a device averaging 8 watts for 24 hours per day would consume:

8 × 24 × 365 ÷ 1,000 = 70.08 kWh/year

At 25p/kWh:

70.08 × £0.25 = £17.52/year

Our Smart Home Electricity Cost Calculator performs this calculation automatically and allows you to enter your own electricity tariff.

How to Measure Your Smart Home's Actual Electricity Use

Manufacturer specifications can be useful, but measuring a device under real-world conditions can produce a better estimate.

Power consumption isn't necessarily constant.

A device may have:

• Active consumption.
• Idle consumption.
• Standby consumption.
• Sleep modes.
• Short periods of higher power demand.

For suitable plug-in appliances, an energy-monitoring smart plug or plug-in electricity meter can help measure consumption over several hours or days.

Longer measurement periods are often more useful than a single instantaneous wattage reading because they capture changes in activity.

See our Best Smart Plugs UK guide for smart plugs with energy-monitoring features.

Don't Use the Power Adapter Rating as Actual Consumption

This is an easy mistake to make.

Suppose a smart speaker's power adapter says:

15W

That does not necessarily mean the speaker continuously consumes 15 watts.

The adapter needs to be capable of providing sufficient power when required, while the device's actual consumption may be lower during normal operation.

Using the adapter's maximum rating as continuous consumption can therefore significantly overestimate annual energy use.

Measured average consumption is preferable where available.

Do Smart Plugs Increase Electricity Consumption?

Technically, yes.

A smart plug contains electronics and wireless connectivity that require power.

The more useful question is whether the plug helps save more electricity elsewhere than it consumes itself.

Suppose a smart plug enables you to automatically turn off an appliance that would otherwise consume significant electricity unnecessarily.

The electricity saved by that automation could exceed the electricity required to operate the smart plug.

However, using a smart plug solely to eliminate tiny standby consumption may not always produce meaningful savings.

See our Smart Plug vs Smart Switch comparison for more information.

Do Smart Bulbs Use Electricity When They're Off?

Yes, generally a small amount.

A conventional bulb physically disconnected from electricity at the wall can't consume power.

A smart bulb that's been turned off through Alexa, Google Home, Apple Home or its manufacturer's app normally remains electrically powered.

Its wireless electronics need to remain available so the bulb can receive the next command.

This standby consumption is one reason smart bulbs should be assessed differently from conventional bulbs.

However, their overall energy use also depends heavily on how efficient the bulb is while producing light and how long it's illuminated each day.

Do Smart Speakers Use Much Electricity?

A smart speaker normally consumes electricity continuously while plugged in.

Actual consumption varies by device and operating state.

Factors can include:

• Model and hardware.
• Speaker size.
• Audio playback.
• Volume.
• Wireless activity.
• Smart-home processing.
• Whether the product includes a display.

Because smart speakers are commonly left powered throughout the year, even modest differences in continuous consumption can accumulate over time.

Do Security Cameras Use a Lot of Electricity?

A single security camera may not be a major household load, but security systems are worth considering because homes can contain several cameras plus additional equipment.

A system could include:

• Front camera.
• Rear camera.
• Side camera.
• Indoor cameras.
• Video doorbell.
• Base station or hub.
• Network equipment.

Some cameras are battery or solar powered, while others draw mains electricity continuously.

When calculating the electricity consumption of a smart security system, include the supporting equipment as well as the cameras themselves.

See our Best Smart Home Security Gadgets UK guide.

What About Robot Vacuums?

Robot vacuums are more complicated because electricity consumption isn't constant.

A robot may consume relatively little while sitting charged on its dock, considerably more while charging, and additional electricity during cleaning or when a sophisticated dock empties dust, washes mop pads or dries them.

For that reason, annual consumption is better calculated from measured energy over a representative period rather than simply treating the dock's maximum rated wattage as a continuous load.

Can Smart Home Technology Reduce Electricity Use?

Smart-home devices aren't automatically energy-saving devices.

Some consume electricity primarily to provide convenience, entertainment or security.

Others can potentially help reduce waste elsewhere.

Examples include:

• Smart heating schedules.
• Room-by-room heating control.
• Lights automatically switching off when rooms are empty.
• Appliances operating according to schedules.
• Energy-monitoring smart plugs identifying inefficient devices.
• Automations responding to occupancy.

The important calculation isn't simply:

How much electricity does the smart device consume?

It's also:

Does the automation reduce more energy consumption elsewhere than the smart technology adds?

We've covered suitable products in our Best Smart Home Gadgets for Saving Energy UK guide.

Smart Heating Can Be Different

Heating deserves special consideration because the electricity required to power a thermostat or smart radiator control can be tiny compared with the energy used to heat a home.

The purpose of a smart heating system isn't necessarily to consume less electricity itself. It's to provide more precise control over a much larger household energy load.

Features can include:

• Heating schedules.
• Room-by-room temperature control.
• Remote control.
• Open-window detection.
• Occupancy-related automation.

Whether these features reduce your bills depends on how you previously heated the property and how you configure the system.

Smart Home Electricity Use vs Standby Power

Traditional household appliances can also consume electricity while apparently switched off.

That means it would be misleading to assume all smart-home electricity consumption is additional.

For example, replacing an existing device with a connected equivalent may change its standby consumption rather than introducing an entirely new load.

The most useful comparison is therefore between:

the electricity consumption of your current setup and the electricity consumption of the alternative setup.

How Much Does 1 Watt Cost Per Year in the UK?

The answer depends on your electricity tariff.

One watt consumed continuously equals 8.76 kWh per year.

This is a useful shortcut when evaluating always-on equipment.

If your tariff is 25p/kWh, for example, a continuous 10-watt load costs approximately £21.90 annually.

Does the Electricity Standing Charge Matter?

When calculating how much an individual smart-home device costs to operate, we generally exclude the household electricity standing charge.

The standing charge is normally payable regardless of whether a particular smart speaker, bulb or plug is operating.

For comparing devices, the relevant figure is therefore your electricity unit rate in pence per kWh.

How to Perform a Smart Home Energy Audit

If you want to know how much your own smart home consumes, use this process.

Step 1: List Every Mains-Powered Smart Device

Include speakers, displays, plugs, bulbs, hubs, cameras, doorbell equipment, heating controllers and charging docks.

Step 2: Include Supporting Equipment

Consider network equipment such as dedicated hubs and additional mesh nodes required by the system.

Step 3: Measure Consumption

Use reliable published measurements or an electricity-monitoring device where appropriate.

Step 4: Record Daily Operating Time

Use 24 hours for equipment that's genuinely powered continuously.

Step 5: Calculate Annual kWh

Multiply watts by operating hours and convert to kWh.

Step 6: Enter Your Electricity Rate

Use your actual tariff rather than a national average.

Step 7: Add Everything Together

This gives you an estimate of the total annual electricity consumption attributable to your smart-home equipment.

Our electricity cost calculator can handle the individual calculations.

Should You Switch Smart Home Devices Off at Night?

Not necessarily.

Some devices need to remain powered to perform their intended function.

Switching off equipment such as:

• Security cameras.
• Video doorbells.
• Home-security hubs.
• Routers.
• Heating controls.
• Essential smart-home hubs.

could disable features you rely on.

Instead of indiscriminately switching everything off, identify devices with significant unnecessary consumption.

Turning off something consuming 20 watts unnecessarily is much more valuable than obsessing over a useful device consuming a fraction of a watt.

Is a Smart Home Expensive to Run?

Not necessarily.

The cost depends far more on the devices chosen than on whether a home is labelled "smart".

A system built mainly around low-power sensors, a few smart plugs and efficient bulbs could have relatively modest additional consumption.

A complex installation containing multiple displays, cameras, hubs, networking equipment and charging stations could use substantially more.

The best approach is therefore to measure rather than guess.

Our Verdict

Smart-home devices can add to household electricity consumption, particularly because many connected products remain powered continuously.

But the individual wattage of a device only tells part of the story.

The three figures that matter are:

• Average wattage.
• Operating time.
• Your electricity unit rate.

The useful rule to remember is that one watt consumed continuously equals 8.76 kWh per year.

At 25p/kWh, that's £2.19 annually for every continuous watt.

Rather than worrying about every tiny standby load, measure your system, identify the devices responsible for the greatest consumption and consider whether the benefits they provide justify their running costs.

Want to calculate your own setup? Use our free Smart Home Electricity Cost Calculator.

Frequently Asked Questions

How much electricity does a smart home use?

There is no standard figure because smart homes vary enormously. A property's smart-home electricity use depends on the number of connected devices, their average wattage and how long they operate. Measuring your own equipment provides a more meaningful answer than using a generic estimate.

How much does a 50-watt smart-home load cost per year?

A continuous 50-watt load consumes approximately 438 kWh per year. At an illustrative electricity rate of 25p/kWh, that would cost approximately £109.50 annually.

Do smart devices increase electricity bills?

Mains-powered smart devices consume electricity and therefore contribute to your bill. However, some devices may also help reduce consumption elsewhere through heating control, schedules, occupancy automation or energy monitoring.

Do smart devices use electricity when switched off?

Some do. A smart bulb or smart plug that's switched off through software normally still requires a small amount of standby electricity so its wireless electronics can remain connected.

Do smart plugs save electricity?

A smart plug can help save electricity if its scheduling or automation prevents a connected appliance from consuming unnecessary energy. The smart plug also consumes a small amount of electricity itself, so the net saving depends on the appliance and how the plug is used.

How much electricity does an always-on device use?

Every watt consumed continuously uses approximately 8.76 kWh per year. Multiply 8.76 by the device's average wattage to estimate its annual kWh consumption.

What's the best way to measure smart-home electricity consumption?

For suitable plug-in devices, use an energy-monitoring plug or electricity meter and measure consumption over a representative period. This is usually more useful than relying on the maximum wattage printed on a power adapter.

Related Smart Home Guides

• Smart Home Electricity Cost Calculator
• Best Smart Home Gadgets for Saving Energy UK
• Best Smart Plugs UK
• Best Smart Home Gadgets UK
• Best Smart Sensors UK
• Smart Plug vs Smart Switch
• How to Start a Smart Home
• UK Smart Home Statistics 2026