Budget and prices
What a smart home actually costs to run for a year
Standby watts, subscriptions and hardware spread over its life, costed at the Ofgem price cap electricity rate of 26.32p per kWh for October to December 2026.
Three numbers decide what a smart home costs you each year: the electricity its always-on devices draw, the subscriptions attached to them, and the hardware spread over the years you keep it. Only the third appears on a price tag.
This guide computes all three at the published price cap rate so the arithmetic is checkable. Device wattages are examples chosen to show the shape of the problem, and the prices were checked on 2026-11-03.
Standby is the whole electricity story
A smart device is never off. A plug that switches a lamp is itself drawing power 24 hours a day so that it can hear the instruction to switch, and that continuous draw, not the switching, is what appears on a bill.
The sum is one line. Watts multiplied by 24 hours, multiplied by 365 days, divided by 1,000, gives kilowatt hours a year. At the Ofgem price cap unit rate for 1 October to 31 December 2026 — 26.32 pence per kWh for a direct debit customer in England, Scotland and Wales — a device drawing a steady 1 W costs about £2.31 a year.
Scale that across a real household and it stays modest. Twelve plugs at 1 W, a hub at 3 W and two speakers at 2.5 W each come to 175.2 kWh a year, or about £46. For comparison, the standing charge on the same cap is 54.83 pence a day, which is £200.13 a year before anything at all is switched on.
| Continuous draw | kWh a year | Cost a year |
|---|---|---|
| 0.5 W | 4.4 kWh | £1.15 |
| 1 W | 8.8 kWh | £2.31 |
| 2 W | 17.5 kWh | £4.61 |
| 3 W | 26.3 kWh | £6.92 |
| 5 W | 43.8 kWh | £11.53 |
Each row is watts multiplied by 24 hours and 365 days, divided by 1,000, then multiplied by £0.2632. Rated power on a label is a maximum, so a plug-in meter will usually read lower than this for a device that idles.
There is no energy label to compare these with
The UK energy label covers a defined list of product types: air conditioners and comfort fans, dishwashers, domestic ovens and range hoods, electronic displays including televisions, lighting products, local space heaters, refrigerating appliances, space heaters, tumble driers, washing machines and washer-dryers, water heaters and hot water storage tanks, among others. Smart plugs, hubs, sensors and speakers are not on it.
So there is no A to G class to compare and no product information sheet to download for this category. The only figures available are the rated power on the device's own label and whatever a plug-in meter tells you, and the second is more honest than the first because rated power is a ceiling rather than an average.
Where the label does apply — a smart television, a connected fridge, a heat pump control attached to a labelled appliance — it is worth using. The online selling rules require a dealer to show the energy efficiency class and the range of classes alongside the listing, linked to the full label, with the product information sheet available on a publicly accessible site.
- Smart plugs, hubs, sensors and speakers carry no UK energy label, so there is no class to compare
- Rated power printed on a device is a maximum, not the figure it idles at
- A plug-in meter left on a device for 7 days gives a better annual estimate than any label would
- Televisions, fridges, washing machines and lighting products do carry a label, and the class must be shown in online listings
Subscriptions are usually bigger than the electricity
A camera plan at an example £3.49 a month is £41.88 a year. That single line is roughly 91 percent of the entire electricity bill computed above for a twelve-plug household, and unlike the electricity it does not fall when you unplug anything.
Subscriptions also compound in a way hardware does not. Over three years that £3.49 plan costs £125.64, which on an example £35 camera is about three and a half times the purchase price. Buying the camera is the small decision; agreeing to the plan is the large one.
The questions that decide whether the plan is worth it are answerable before you pay: does the device record to a local card when the plan lapses, how many days of history does the free tier keep, and does a second camera need a second plan or share the first. A device that keeps a local recording when the plan stops is a device you can cancel.
| Line | Working | Cost a year |
|---|---|---|
| Twelve smart plugs at 1 W | 12 × 8.76 kWh = 105.12 kWh | £27.67 |
| One hub at 3 W | 26.28 kWh | £6.92 |
| Two speakers at 2.5 W | 2 × 21.9 kWh = 43.8 kWh | £11.53 |
| One camera plan | £3.49 a month × 12 | £41.88 |
| Hardware, £320 over 5 years | £320 ÷ 5 | £64.00 |
Electricity rows use 26.32 pence per kWh. The three electricity lines total 175.2 kWh and about £46; with the plan and the hardware the household's figure is about £152 a year.
Hardware is cheap per year if you keep it
An example £320 of plugs, a hub and a pair of speakers, kept for 5 years, is £64 a year. The same £320 replaced after 2 years is £160 a year. Nothing else on this page moves by that much.
What makes the five-year column reachable is the published support period rather than build quality, because a device that stops receiving security updates is a device most households replace. Our hub and protocol guide works through that figure; here it is enough to say that it is the input the annual cost is most sensitive to.
Adding the three lines together for the example household gives roughly £152 a year: about £46 of electricity, about £42 of subscription and £64 of hardware. The order of those three is the useful result, because it says where to look first when the figure feels high.
What to do with the result
If the annual figure matters to you, cancel a subscription before you unplug a sensor: at these figures one example £3.49 a month plan costs the same as about eighteen smart plugs left on standby for a year. If the figure does not matter, the electricity never will, because 175.2 kWh is a fraction of a typical household's consumption.
The lasting saving is in the hardware column, and it is made at the point of purchase rather than afterwards. Choosing a device with a long published support period and a local fallback is what turns £160 a year into £64 a year, and no amount of switching things off at the wall gets near that.
Before you buy
- Write down the rated power of every device that is never switched off
- Multiply watts by 24 and 365, divide by 1,000, and multiply by your own unit rate
- List every subscription attached to the system with its monthly price and multiply by 12
- Check whether each camera records locally when its plan lapses
- Divide your total hardware spend by the years you expect to keep it
- Compare the three totals and act on the largest one first
- Borrow or buy a plug-in meter before assuming any wattage on this page describes your device
Questions readers ask
- How do I find what my devices actually draw?
- A plug-in energy meter left in place for 7 days gives a weekly kWh figure you can multiply by 52, which is far better than the rated power on the label. Rated power is a maximum for the moment a device works hardest, and most smart devices spend their lives idling well below it.
- Why use the price cap rate rather than my own?
- Because it is published and checkable, which makes the arithmetic on this page reproducible. Your own unit rate is on your bill and is the one to use for your own figures. At 26.32 pence per kWh a 1 W device is £2.31 a year; at 30 pence it would be £2.63.
- Is it worth switching smart plugs off at the wall?
- Not usually. A plug at 1 W costs about £2.31 a year, so switching twelve of them off saves about £27.67 and removes the reason you bought them. Cancelling one example £3.49 a month camera plan saves £41.88 and costs you nothing you were using.
- Do smart devices have an energy rating I can compare?
- Plugs, hubs, sensors and speakers are not in the categories the UK energy label covers, so there is no A to G class for them. Televisions, refrigerating appliances, washing machines, dishwashers and lighting products are covered, and online listings for those must show the class and the range of classes alongside the product.
- Does a standing charge change any of this?
- No, because it is charged per day regardless of consumption. At 54.83 pence a day it is £200.13 a year on the current cap, which dwarfs the £46.11 of smart home electricity above and is unaffected by anything you plug in or unplug.
Sources
- Ofgem — Energy price cap unit rates and standing charges: 26.32p per kWh electricity and 54.83p daily standing charge for 1 October to 31 December 2026, direct debit — checked 2026-11-03
- GOV.UK — Regulations: energy information (product categories covered by the UK energy label and the online selling requirements) — checked 2026-11-03
- legislation.gov.uk — Security Requirements for Relevant Connectable Products Regulations 2023, Schedule 1 (defined support period) — checked 2026-11-03
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