Sonoff
Smart home kit, scheduled water heater without exceeding the power limit, Sonoff 25A
Smart home kit, scheduled water heater without exceeding the power limit, Sonoff 25A
Kit smart home su Amazon.it · Energia e fotovoltaico · Elettricista
Regular price
€90.25
Regular price
Sale price
€90.25
Unit price
per
Indicative price: sum of the Amazon.it prices recorded on 22/09/2026. The kit is bought on Amazon, not from us.
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Indicative price: the sum of the Amazon.it prices recorded on 22/09/2026; prices on Amazon can change. Delivery, returns and warranty are shown on Amazon at checkout. As an Amazon Associate, Litio Store earns from qualifying purchases.
Smart home kit · Energy and solar
Sonoff scheduled electric water heater kit 25A
The 25A Sonoff POWR3 relay with metering switches the electric water heater on only during the hours you choose, high-power models included; the POWCT meter on the main line watches the whole house's consumption and switches the heater off before the meter's limit is exceeded. Over Wi-Fi, from the eWeLink app, installation by an electrician.
Sonoff devicesWi-Fi, no hub neededInstallation by an electricianBuying on Amazon.it
Kit put together by Litio Store — buy it on Amazon.it. This is one of the smart home kits in the Domotica Smart section: you buy the products on Amazon from a basket we have already filled, at Amazon's prices on the day, and we earn a small commission at no extra cost to you. For professional LoRaWAN systems see the Milesight kits in the same section; for a kit built to order, get in touch through the contact page.
Who it's forFor anyone with a powerful electric water heater who only wants to heat water when it is needed.
What you controlThe water heater, with a 25A relay and energy monitoring.
What you measureThe total consumption of the house, read at the consumer unit.
InstallationElectrician needed: relay on the water heater line, meter in the enclosure.
What it does
- The POWR3 is fitted on the water heater line and switches it on and off, up to 25A, while measuring its consumption.
- From the eWeLink app you schedule the time slots when the water heater should heat, for example during the cheapest hours or before shower time.
- The POWCT, with the current transformer on the main conductor, measures consumption for the whole house.
- With a scene, if the total goes above the threshold set close to the contract power, the water heater switches off and comes back on when consumption drops.
- The water heater's own thermostat stays active and keeps controlling the temperature.
- The history shows how much energy the water heater takes each day.
To switch the water heater on with the solar surplus, for three-phase water heaters or for more loads to manage, write to us from the contacts section and we will tell you the right kit.
1Sonoff POWR3 25A relay with metering, on the water heater line, next to the cylinder or in the consumer unit.
2Sonoff POWCT meter on the DIN rail in the consumer unit, with the current transformer on the main live conductor.
How to install it
Wi-Fi network. The kit has no hub: the POWR3 and the POWCT connect to the home router on the 2.4 GHz network and are managed from the eWeLink app. Check the Wi-Fi coverage near the water heater, often in the bathroom or a utility cupboard, and near the consumer unit. If the signal is weak, plan for a repeater before installing.
Water heater relay. The POWR3 is fitted on the water heater line, next to the tank or in the consumer unit, to the manufacturer's diagram and with cable cross-sections suited to the power. The circuit must have its own protection sized for the load. The 230V connections in the consumer unit must be made by qualified personnel with the system isolated.
Meter and wiring. The POWCT mounts on the DIN rail in the kit's 4-module enclosure and the current transformer is clamped around the main live conductor downstream of the meter, in the direction indicated. The kit also includes the ferrules for stranded conductors and the Wago lever connectors for wiring the modules.
App and pairing. In the eWeLink app, add the POWR3 and the POWCT with the guided procedure and connect them to the Wi-Fi. Switch the water heater on from the app and read its power on the POWR3; check that the POWCT shows positive consumption with loads running. Give the devices clear names.
Recommended automations. Schedule one or two time slots for the water heater, for example early in the morning and in the afternoon, and check over a week that there is enough hot water. Create a scene that switches the POWR3 off when the POWCT goes above a threshold close to your contracted power and switches it back on a few minutes later. Add a notification.
Contents verified. The POWR3 and the POWCT are Sonoff Wi-Fi devices handled in the same eWeLink app, so the reading at the main incomer can switch the water heater relay off directly. The kit includes the 4-module enclosure for the POWCT with a spare slot, the wire ferrules for the wiring in the consumer unit and the Wago connectors for the modules.
What's in the kit
| Qty | Item | Unit price | Subtotal |
|---|---|---|---|
| 1 | Sonoff POWR3 25A relay with energy monitoringRelay / switch | €36.99 | €36.99 |
| 1 | Sonoff POWCT energy meterEnergy monitoring | 33,40 € | 33,40 € |
| 1 | Wago 221-413 lever connectors, 10 piecesAccessory: connections · connections for the modules | €8.99 | €8.99 |
| 1 | Electraline surface-mount consumer unit, 4 modulesAccessory: DIN enclosure · 1 DIN modules + spare space | €18.73 | €18.73 |
| 1 | Assorted crimp ferrules, 900 piecesAccessory: wiring · wiring inside the distribution board | €11.99 | €11.99 |
| Kit total | 110,10 € |
Prices taken from Amazon.it on 22/09/2026: they can change, and the price shown by Amazon at the time of purchase is the one that applies.
Add the whole kit to your Amazon basket5 items, 5 pieces · the options are added from the individual linksDelivery, returns and warranty: Amazon shows these at the time of purchase.
Before you order
Do you need a hub?
No. The Sonoff devices in the kit are Wi-Fi and connect straight to the home router on the 2.4 GHz network; they are managed from the eWeLink app. Good Wi-Fi coverage is needed where the consumer unit is, and metal enclosures and cellars cut it down.
Does it work with Alexa, Google or Apple?
The kit is managed from the eWeLink app, with consumption charts and scenes. Through the eWeLink skill and integration, the relays can also be controlled from Alexa and Google Home. Energy readings and consumption-based automations are best kept in the eWeLink app.
Do you need an electrician?
Yes. The devices are fitted in the consumer unit or on 230V lines: the work must be done by qualified personnel with the system isolated. The kit includes an enclosure, wire ferrules and connectors for tidy wiring.
What happens if the internet goes down?
The devices keep measuring and the relays can still be operated with their own button. From the eWeLink app on the home network, LAN mode allows some local control as stated by the manufacturer; notifications, cloud scenes and access from outside the home resume when the line is back.
Can I add more devices?
Yes. In the same eWeLink app you can add more metering relays, smart plugs and Sonoff switches. Write to us from the contact page if you would like a kit built around your own consumer unit. Every extra device is paired with the same guided procedure in the app.
Do I need to buy any batteries?
No. Every device in the kit runs off mains power and uses no batteries. So there are no spares to keep at home and no charge levels to check: if the power goes off, the devices stop and start again on their own when it comes back.
Does the water heater run out of hot water?
Not if time slots are enough: the POWR3 switches the water heater on at the set times and its own thermostat holds the temperature. If it is shed because consumption is too high, the water heater restarts once the house drops back below the threshold. The time slots can be changed from the app at any time.
What if a product is out of stock on Amazon?
It happens, especially with multipacks and newly released products. Write to us from the contacts section with the kit code and the product you can't find: we'll point you to an alternative that fits the rest of the kit, so it keeps working as described.
Why buy on Amazon?
We put the kit together and tested it ourselves, picking the parts and checking that they work together. Purchase, payment, returns and warranty are handled by Amazon: delivery times, returns and warranty are shown on Amazon at the time of purchase, item by item.
Notes
Not included
- Wi-Fi router and a repeater if needed
- The water heater and its maintenance
- Electrical work, protective devices and cabling for the water heater line
- A box for the relay next to the water heater, if needed
As an Amazon Associate, Litio Store earns from qualifying purchases.