HEDNO (ΔΕΔΔΗΕ) smart meters in Greece: what data they provide, what the H1 port is and how a smart home uses it

In short: HEDNO (ΔΕΔΔΗΕ), the Greek distribution network operator, is replacing every electricity meter in the country with a smart meter: about 1.6 million were installed by June 2026 and the target is 7.7 million by 2030. The new meters record consumption every 15 minutes and send it over the mobile network. You see the data in the Metering Data Portal with a one-day delay. The meters also have an H1 port for real-time data, but for households it is not yet practically available. For real-time automation, the solution today is your own energy meter in the panel.

In our article on dynamic tariffs we saw that the smart meter is the "ticket" to hourly prices. Here we look at the meter itself: what it measures, where the data goes and how a home with automation uses it.

The programme in numbers

Meters installed	About 1.6 million (June 2026)
Installation pace	More than 4,500 a day (September 2026)
End-2026 target	About 2.4 million
2030 target	7.7 million, meaning every meter
First call-off contract	2.76 million meters and a new central meter data management system (May 2025)
Suppliers	Three consortia: Iskraemeco with Oracle, Itron with ZIV, Protasis with Sagemcom
Communication	Mobile network (NB-IoT and LTE-M)
Recording	Every 15 minutes

HEDNO prioritises supplies with frequent disconnections and reconnections, meters that are hard for crews to reach, and supplies with high consumption or a risk of electricity theft. The pace is increasing, so if you do not have a smart meter yet, you will probably get one within the next few years without doing anything.

What a smart meter does that the old one did not

• Remote reading. Readings are taken remotely. No more estimated bills or visits to read the meter.
• A 15-minute load profile. The meter records not just the total but how much energy you used in each 15-minute interval. This is needed for dynamic tariffs and for net billing.
• Bidirectional metering. It records separately the energy you take from the grid and the energy you feed in, for example from solar panels.
• Data for the grid. HEDNO sees voltages, loads and faults in much greater detail.

One point worth knowing: according to the RAAEY decision of December 2025, for many household meters the 15-minute data had not yet been certified and sent to suppliers. To join a dynamic tariff, your meter is added to a special registry of supplies with certified data. HEDNO first collects one month of measurements. The process starts through your supplier.

Where you see your data

Channel	What it provides	Delay
HEDNO Metering Data Portal (TAXISnet login)	Consumption, production and injection curves	Next day at best
myDEDDIE app	Supply and consumption details	Next day
Portal API (with access token)	Curves per 15 minutes, hour, day or month, up to 2 years back	Next day
H1 port on the meter	Energy, power, voltages, currents, frequency every 10 seconds	Near real time, but not yet available to households

Next-day data is very useful for analysis: when the house consumes, what the night-time base load is, how much solar production is self-consumed. It is not enough for automation, which needs to know what is happening right now.

The H1 port: it exists, but not for you yet

EU Directive 2019/944 requires smart meters to be able to give consumers near-real-time data. In Greece, RAAEY decision E-283/2025 (Government Gazette B' 6788/17.12.2025) sets out the following:

• All meters from the national rollout have a standardised H1 port, providing data every 10 seconds: energy, power, power factor, voltages, currents, frequency.
• About 330,000 older household meters (pre-2019) have neither an H1 port nor a pulse output. RAAEY asked HEDNO to upgrade or replace them.
• Activation only happens on request by the user and through a dedicated HEDNO device (H1 dongle) using Wi-Fi or NB-IoT. The programme foresees 2.3 million such devices by 2030, with priority for medium-voltage supplies and specific low-voltage categories. According to the Gazette, it "does not in principle concern ordinary household consumers".

Put simply: the capability is in the hardware, but a household today cannot connect anything to the HEDNO meter on its own. The meter is sealed and any tampering with it is prohibited.

The solution today: your own meter in the panel

If you want the home to react in real time, a second energy meter of your own goes into the electrical panel, downstream of the HEDNO meter. It does not replace the billing meter. It gives the automation the data it needs, second by second.

Solution	Example	Connection to automation	When it fits
MID-certified KNX meter	Ekinex EK-ME1-5TA-TP (three-phase, with current transformers)	Directly on KNX	Homes with a KNX installation
MID-certified DIN-rail Modbus meter	Eastron SDM630 (three-phase), SDM120 (single-phase)	Modbus to a KNX gateway or Home Assistant	Professional installations with many circuits
DIN-rail meter with current clamps (CT)	Shelly Pro 3EM	Ethernet or Wi-Fi, local API and MQTT, Home Assistant integration	Quick addition without rewiring circuits
Solar inverter meter	Depends on the manufacturer	Inverter Modbus or API	When a hybrid inverter is already installed

The choice depends on what is already in the home. In a KNX installation, a KNX meter is the cleanest option: power and energy values are available to every logic block and every display without intermediate systems. In every case we prefer devices that work locally, without the cloud.

What automation does with this data

With real-time metering, the home can:

1. Shift loads to cheap hours. Water heater, washing machines, pre-heating or pre-cooling the home start when the dynamic tariff price is low.
2. Use surplus solar production. When the meter shows export to the grid, the automation switches on loads instead of giving energy away.
3. Charge the electric car without tripping the main breaker. The charger adjusts its power based on the rest of the home's consumption.
4. Protect against overload. If the oven, air conditioners and charger run at once, the automation temporarily limits the less critical loads.
5. Spot waste. An unusually high night-time base load or an air conditioner that never switches off shows up immediately, with a notification.

Heating and cooling automation is usually the largest load that can be shifted without occupants noticing, which is why it is almost always combined with energy metering.

What to do now

1. Log in to the Metering Data Portal with TAXISnet and check whether your meter is telemetered.
2. Download a few months of data. You will see when you consume and whether a dynamic tariff makes sense for you.
3. If you are considering a dynamic tariff, ask your supplier about adding your meter to the certified data registry.
4. If you want automation, leave room in the panel for an energy meter. In a renovation or a new panel, the cost is small.
5. Do not touch the HEDNO meter. Everything happens downstream of it, in your own installation.

How Sync-Teq helps

We design home energy management as part of the automation: an energy meter in the panel, integration with KNX or Home Assistant, and scenarios for dynamic tariffs, solar and EV charging. Get in touch to see what suits your home.

Sources

• RAAEY E-283/2025, Government Gazette B' 6788/17.12.2025: H1 port, near-real-time data, certified data registry (Greek)
• RAAEY: decision text (ΑΔΑ 9ΗΞΘΙΔΞ-ΒΧ5) (Greek)
• HEDNO reply to the Hellenic Parliament (24.03.2026): NB-IoT/LTE-M, 15-minute data (Greek)
• HEDNO: Metering Data Portal
• SKAI/ANA: contract for 2.76 million smart meters (28.05.2025) (Greek)
• Capital.gr: 4,500 smart meters a day and targets to 2030 (Greek)
• Businessdaily: orange tariffs for households (01.04.2026) (Greek)
• Directive (EU) 2019/944
• Shelly Pro 3EM: specifications
• Eastron SDM630 Modbus
• Ekinex: three-phase MID meter for KNX