

In the board the Shelly Pro 3EM measures the shop's electricity use, phase by phase and hour by hour, and the Sonoff AirGuard CO2 monitor tells you when the air really does need changing. So you see where the energy goes and open up or run the ventilation only when it is needed, without throwing away heating or cooling.
What it does
- The Shelly Pro 3EM measures power and energy on three phases, or on three single-phase circuits as the manufacturer sets out.
- The Shelly app shows consumption by hour, day and month: you find the loads left on with the shop shut and the peaks during opening hours.
- The Sonoff AirGuard CO2 monitor measures the CO2 in the room and shows it in the eWeLink app.
- When CO2 goes above the chosen threshold you get an alert: open up or switch on the ventilation only then, instead of leaving doors open with the air conditioning running.
- The Shelly Pro 3EM goes to the router on a network cable: the readings do not depend on Wi-Fi.

How it is installed
What's in the kit

| Qty | Item | Unit price | Subtotal |
|---|---|---|---|
| 1 | Shelly Pro 3EM three-phase meterEnergy metering | 69,90 € | 69,90 € |
| 1 | Sonoff AirGuard CO2Air quality | 56,27 € | 56,27 € |
| 1 | BTicino surface-mount enclosure 8 modulesAccessory: DIN board · 3 DIN modules + spare | 18,50 € | 18,50 € |
| 1 | Assorted crimp ferrules, 900 piecesAccessory: wiring · wiring inside the board | 11,99 € | 11,99 € |
| 1 | Wago 221-413 lever connectors, 10 piecesAccessory: connections · connections inside the board | 8,99 € | 8,99 € |
| 1 | deleyCON Cat6 network cables 1 m, 5 piecesAccessory: network · connections inside the board | 11,18 € | 11,18 € |
| 1 | deleyCON Cat6 network cable 10 mAccessory: network · connection to the router | 9,70 € | 9,70 € |
| Kit total | 186,53 € |
Prices taken from Amazon.it on 22/09/2026: they can change, and the price Amazon shows at the time of purchase is the one that applies.
Add the whole kit to your Amazon basket7 items, 7 pieces · optional extras are added from the individual linksDelivery, returns and warranty: Amazon shows these when you buy.
Before you order
Do you need a hub?
No. The Shelly Pro 3EM connects to the router with a network cable or over Wi-Fi, the CO2 monitor connects to the eWeLink app. The shop router with an internet connection is enough.
Why two different apps?
The meter is Shelly and the CO2 monitor is Sonoff: each has its own app, with charts and alerts. If you want everything in one place, you can link both to Alexa, Google Home or Home Assistant.
Does it work with Alexa and Google?
Yes. The Shelly Pro 3EM connects through the Shelly skill for Alexa and the Shelly integration in Google Home; the Sonoff monitor through eWeLink. Consumption and history still come from the manufacturers' own apps.
Do you need an electrician?
Yes, for the meter: it mounts on DIN rail and is powered in the board, with the clamps on the phases. 230V connections must be made by qualified personnel, with the installation isolated. The CO2 monitor, on the other hand, you can fit yourself.
The shop has a single-phase supply: is that all right?
The Shelly Pro 3EM is a three-phase meter, but as the manufacturer sets out it can also measure three separate single-phase circuits, for example lighting, sockets and air conditioning. Tell the electrician which circuits you want measured.
What happens if there is no internet?
The meter keeps measuring and keeps the data as the manufacturer describes; the CO2 monitor keeps reading. Without internet you cannot see the charts remotely and you get no alerts until the connection returns.
Can I add devices?
Yes. In the Shelly app you can add relays to switch the ventilation or the sign, metering sockets and more meters; in the eWeLink app, more Sonoff sensors. Get in touch through the contact page to turn the metering into automatic control.
What if a product is out of stock on Amazon?
It happens, above all with multipacks. Get in touch through the contact page quoting the kit code and the item that is missing: we will point you to an alternative that works with the rest of the set, so you can finish the order without changing the other parts.
Why buy on Amazon?
Purchase, payment, delivery, returns and warranty are handled by Amazon: delivery times, returns and warranty are shown on Amazon when you buy. The kit itself is our own work: we picked parts that work together, plus the accessories needed to fit them.
Notes
Not included
- A router and an internet connection
- Ventilation system or air conditioner
- Protective breakers in the board
- 230V electrical work
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