Smart plugs are often marketed as instant energy savers, but the reality is far more nuanced. A smart plug is essentially a relay with connectivity: it opens and closes the current flow from your phone, on a schedule, or according to a rule. Everything else depends on what you plug into it and how you pay for electricity. TechNews DevTop breaks down what these devices can genuinely deliver, where they fall short, and the safety thresholds that vary from one model to the next.
- Savings come from timing, not magic: Smart plugs only cut bills when paired with time-of-use tariffs and large appliances, with one consumer group estimating around 25 euros per month under ideal conditions.
- Standby draw can backfire: A plug like the TP-Link Tapo P110 consumes 0.64 W with the relay off and 1.64 W with it on, which can exceed the standby consumption of a modern television.
- Power limits are model-specific: The Tapo P110 supports 3,680 W and 16 A, while the European Tapo P100 caps a heater at 10 A and 2,300 W, and continuous loads should stay at or below 80% of the rated maximum.
Where the savings actually come from
The financial case for smart plugs rests on shifting consumption, not on the plug optimizing anything by itself. The OCU, a Spanish consumer organization, laid this out in a February 2025 guide: combined with a tariff that has hourly tiers and connected to large appliances, a smart plug could save roughly 25 euros per month. The organization itself cautions that results depend heavily on usage patterns and electricity price fluctuations.
That figure looks optimistic for an average household, for a specific reason: several of the highest-consuming motor-driven appliances, such as air conditioners and washing machines, should not be controlled with this type of plug according to manufacturers themselves. The same guide also warns against “energy saver” boxes sold on the same shelf, which promise savings of up to 90%. These are capacitors that do not reduce household bills and, according to the organization, may even slightly increase them.
The case where the plug costs more than it saves
A smart plug always consumes power because it must stay connected. The TP-Link Tapo P110, for example, declares 0.64 W with the relay off and 1.64 W with the relay on in its public specifications. Run the numbers: 0.64 W across all 8,760 hours of a year amounts to about 5.6 kWh; if the relay stays on all year, 1.64 W adds up to roughly 14.4 kWh.
Compare that with what you intend to cut. Since March 1, 2021, EU Regulation 2019/2021 limits electronic displays, televisions included, to 0.50 W in standby mode and 2.00 W in networked standby, with small tolerances for additional functions. If you use a 0.64 W plug to fully shut off a TV whose standby draw is already 0.50 W, you have increased consumption.
Appliances with standby consumption higher than the plug’s own draw are a different story: there, it can pay off, and the only way to know is to measure. The most useful feature of a plug with consumption monitoring is not switching things off but showing you how many kWh each device uses so you can decide with data.
The safety rule: the manufacturer sets the limit, model by model
Never connect anything that exceeds the maximum load the manufacturer declares for your specific plug, and do not push it to the limit for hours. TP-Link states plainly in its guidance on plugs that heat up that connecting a device exceeding the maximum load and power can cause safety problems and even a fire. If the plug is too hot to touch or smells burnt, stop using it.
What is interesting is that limits change from one model to another within the same brand. The Tapo P110 specification lists a maximum load of 3,680 W and 16 A. By contrast, the supported load table TP-Link publishes for the European Tapo P100 sets 10 A and 2,300 W for a heater, 2,300 W for a kettle or steam iron, and 600 W for a PC. Two plugs that look nearly identical, two different ceilings.
That same page adds three guidelines worth applying to any brand:
- Continuous use, 80% at most. If the device will run for hours, the load should not exceed 80% of the maximum rated power. On a 2,300 W plug, that leaves a practical ceiling of 1,840 W.
- Be careful with motors. The manufacturer considers these plugs suitable mainly for resistive loads such as heaters, kettles and irons, but not for high-power motor or compressor appliances like air conditioners, refrigerators or washing machines, due to the current spike at startup.
- Power strips: add it all up. If you connect a power strip to the smart plug, the combined power of everything on it cannot exceed the plug’s maximum.
The practical conclusion is uncomfortable but clear: a 2,000 W heater connected for hours to a 2,300 W plug falls outside the manufacturer’s own recommendation. Read the specification for your model, not the one on the box next to it.
Wi-Fi, Zigbee or Matter: how you control it
Wi-Fi models like the P110, which operates on 2.4 GHz, connect directly to the router and are controlled through the manufacturer’s app or assistants such as Alexa or Google Assistant.
Zigbee is a different standard with its own mesh network in which devices relay signals to each other, designed for low power consumption and using 128-bit AES encryption, according to the Connectivity Standards Alliance that manages it. Since it is not Wi-Fi, check the specifications for which gateway or hub it requires before buying.
Matter is the layer attempting to bring order: according to the same alliance, it runs over Wi-Fi and Thread and uses Bluetooth for initial setup. Apple, for instance, supports Matter outlets in the Home app and, since iOS 18, allows adding them without a home hub, though it recommends having one for the best experience. TP-Link already sells versions carrying the Matter label, such as the Tapo P110M.
On cybersecurity there is good regulatory news: since August 1, 2025, radio equipment that connects to the internet must meet cybersecurity requirements in the EU under Delegated Regulation (EU) 2022/30, whose application date was delayed by Delegated Regulation (EU) 2023/2444. That does not exempt you from protecting your account and keeping devices updated. It is also worth reviewing what data the manufacturer’s app sends to the cloud.
If you are buying one, the recommendation is to pay a little more for a model that measures consumption and accept that its value lies in information, not in switching things off. Use it to audit devices for a few weeks, schedule the ones that genuinely support timers, and leave the standby TV alone. And if someone suggests using it with the living room heater, reach for the specification sheet before the screwdriver: the number that matters is not the appliance’s, it is the plug’s.