Searches for "smart power strip" are up 489%, to about 9,900 a month, according to Exploding Topics. The pitch: your TV, console and chargers sip power all night, so let an app cut them off. But a smart plug is itself a small always-on gadget. Does the maths work?
The short answer: Yes, modestly, and only on the right sockets. A smart plug draws roughly 0.6 to 1.6 watts of its own, so it must switch off more than that to break even. On a TV corner you can save around $10 to $15 a year at US prices. On a single phone charger you lose money.
How much power is idling right now?
Lawrence Berkeley National Laboratory, which has tracked standby power for decades, puts it at about 5 to 10% of household electricity. A typical home has 40 or more products drawing a trickle, and a constant 1 watt adds up to about 9 kWh a year.
In an LBNL whole-house study, the biggest losers were televisions, set-top boxes and printers. Newer kit is better: the EU has capped most products at 0.5 W in standby since 2013. The US Department of Energy's advice is blunt: put such devices on power strips or smart plugs and switch them off completely.
The plug's own appetite
TP-Link's spec sheet for the popular Tapo P110 lists 1.64 W with the relay on and 0.64 W with it off. Over a year the plug alone uses about 6 to 14 kWh, roughly $1 to $2.60 at the US average of 18.16 cents per kWh (August 2026).
Rule of thumb: a smart plug pays off when the gadgets behind it idle at more than about 2 W combined. One modern charger does not clear that bar. A cable box, a console in rest mode, a soundbar and a TV together usually do.
A worked example (hypothetical)
Take three sockets in an imaginary home billed at 18.16 cents per kWh. The idle wattages are assumptions, not measurements of any product. The plug's own cost uses the Tapo P110 figures above.
| What is on the plug | Assumed idle draw | Hours idle per day | Gross saving | Plug's own cost | Net per year |
|---|---|---|---|---|---|
| TV, cable box, console, soundbar | 10 W | 20 | 73 kWh, $13.26 | 7 kWh, $1.28 | About $12 saved |
| Desk: monitor, printer, speakers | 5 W | 16 | 29 kWh, $5.30 | 8.5 kWh, $1.55 | About $3.75 saved |
| One phone charger | 0.5 W | 20 | 3.7 kWh, $0.66 | 7 kWh, $1.28 | About $0.60 lost |
That first row matches real-world data. Energy Trust of Oregon's 2018 pilot of load-sensing strips on TV setups measured about 77 kWh a year saved per strip; the programme now credits 61 kWh. At today's US price that is $11 to $14. Useful, not life-changing, and roughly a one-to-two-year payback on a $10 to $25 plug.
Smart plug or smart power strip?
A smart plug controls one socket. A smart strip such as the Kasa HS300 gives you six individually switchable outlets, three USB ports and a 15 A, 1,875 W total limit, plus surge protection. One Wi-Fi radio, several devices: for a media cabinet that is the efficient choice.
Energy-monitoring models earn their keep in week one. The P110 shows live watts and seven-day totals, so you measure your own idle loads instead of guessing, and can auto-off a charger once its draw stays low.
If you buy new, look for the Matter logo. Matter is the shared standard backed by Amazon, Apple, Google and Samsung SmartThings, so one plug works in whichever app you prefer. Apple lets you add Matter accessories without a home hub on iOS 18 or later, though it recommends one. Google needs a Nest speaker, display or Google TV Streamer as the hub, plus IPv6 on your router.
Most plugs, Matter or not, still join on 2.4 GHz Wi-Fi only. Worth remembering if you have just moved to a new Wi-Fi 7 router.
Safety: the heater question
Space heaters are the one job to refuse. The FDNY's advice is to plug heaters directly into wall outlets and never into power strips or extension cords. A 1,500 W heater sits at the edge of a plug's 15 A, 1,800 W rating, with nothing to spare. The same goes for air conditioners, kettles and motors above the plug's stated horsepower.
Two more rules from the spec sheets: keep plugs indoors within their rated temperature range (0 to 35 °C for the P110), and never daisy-chain a smart strip into another strip.
Which devices to plug in: a checklist
- TV corner first: TV, cable box, console, soundbar on one smart strip. Leave the router on an always-on socket.
- Desk cluster second: monitor, printer, speakers, lamp. Schedule it off overnight and at weekends.
- Kitchen gadgets with clocks: coffee machine, microwave, air fryer. Small, easy wins.
- E-bike, scooter and tool chargers: auto-off once full, the same idea as phone charging limits.
- Never: space heaters, air conditioners, kettles, medical equipment, fridges and freezers.
- Not worth it: a single phone charger or anything that already idles under 1 W.
Frequently asked questions
Will cutting power damage my TV or console?
TVs cope fine with losing mains; it is no different from a power cut. Consoles are touchier: a rest-mode download or an unsaved game can be lost, so switch off only after the console has shut down.
Do I need Matter, or is the maker's app enough?
The maker's app is enough for schedules and a bill estimate. Matter matters when you want the plug in Apple Home, Google Home or Alexa alongside other brands. It does not change the energy figures.
Buy one energy-monitoring plug before you buy five. Move it around the house for a week, read the idle watts, and let the numbers pick the sockets. Over 2 W and unused most of the day is a candidate; under that is noise.
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