Does my smart meter have a P1/HAN port?

Most European smart meters installed after 2015 have P1/HAN ports. Check for an RJ12 connector on the meter, or contact your utility company. Older meters typically don't have this port.

What's the difference between CT clamps and P1?

P1 reads data directly from your utility meter - easy but only total consumption. CT clamps physically measure current and can be placed on individual circuits, but require electrical installation.

Do I need an electrician for installation?

For P1 and smart plugs: No. For CT-based meters in your electrical panel: Yes, it's legally required in most places and dangerous without experience. Budget $70-140 for installation.

Can I see consumption per room?

Not directly with main meter. Use either Emporia Vue with CT on each breaker, or smart plugs on larger appliances. Combination of both gives best insight.

Typically 10-20% by identifying power hogs and shifting consumption to cheap hours. With dynamic electricity rates, savings can be even higher.

Does energy monitoring work with solar panels?

Yes! Bi-directional meters (Shelly 3EM, HomeWizard P1) can measure both import and export. Home Assistant Energy Dashboard shows production, consumption, and net usage.

Energy Management & Monitoring

Energy Savings Local

Energy monitoring is the foundation for smart power management. By measuring your consumption, you can identify power hogs, optimize usage, and save money - especially with dynamic electricity rates.

📊 Types of Energy Monitoring

Measurement Levels

Type	What’s measured	Best for	Example
Smart Meter Port	Whole house via utility meter	EU countries	HomeWizard
Main meter	Grid input	Total overview	Shelly 3EM
Per circuit	Individual breakers	Find power hogs	Emporia Vue
Per device	Single appliance	Precise measurement	Smart plug

What Should You Choose?

graph TD
    A[Does your meter have P1/HAN port?] -->|Yes| B[HomeWizard P1 Meter]
    A -->|No| C[Do you want per-circuit monitoring?]
    C -->|Yes| D[Emporia Vue 3 or IoTaWatt]
    C -->|No| E[Shelly EM or 3EM]

🇪🇺 Smart Meter Ports - Europe

Many European smart meters have a P1/HAN port providing real-time data:

HomeWizard P1 Meter

Price: ~$50

Why HomeWizard?

HomeWizard is the easiest solution for homes with smart meters:

✅ Plug-and-play (5 min installation)
✅ Works with Home Assistant certified
✅ Real-time data (1 sec updates)
✅ No electrical installation
✅ Local API (no cloud)
✅ Import AND export measurement
✅ Gas and water support (with extra devices)

Disadvantages:

❌ Requires P1/HAN port on meter
❌ Only total consumption (not per circuit)

HA Integration

HomeWizard is auto-discovered:

# No configuration needed!
# Settings → Devices → Add Integration → HomeWizard

# Entities you get:
# - sensor.p1_meter_active_power (W)
# - sensor.p1_meter_total_energy_import (kWh)
# - sensor.p1_meter_total_energy_export (kWh)
# - sensor.p1_meter_active_voltage_l1 (V)

# Energy Dashboard
# Settings → Dashboards → Energy
# Grid consumption: sensor.p1_meter_total_energy_import
# Return to grid: sensor.p1_meter_total_energy_export

Buy: HomeWizard.com, Amazon

⚡ Shelly Energy Meters

Shelly Lineup

Model	Phases	Channels	Price ~	Best for
Shelly EM Gen3	Single	2	$55	Budget
Shelly Pro EM-50	Single	2	$70	DIN mounting
Shelly Pro 3EM	3-phase	3	$140	Whole house
Shelly Pro 3EM-400	3-phase	3 (400A)	$170	Large installations

🏠 Shelly Pro 3EM

Why Shelly Pro 3EM?

Price: ~$140

Shelly Pro 3EM is best for whole-house monitoring:

✅ WiFi + Ethernet (stable)
✅ 3 phases up to 120A each
✅ Bi-directional (import/export)
✅ DIN-rail mounting
✅ ±1% accuracy
✅ Local API + MQTT
✅ Native HA integration

Disadvantages:

❌ Requires electrical installation
❌ Only main monitoring (not per circuit)

HA Integration

# Shelly auto-discovered
# Settings → Devices → Add Integration → Shelly

# Entities per phase:
# - sensor.shelly_pro_3em_phase_a_power
# - sensor.shelly_pro_3em_phase_a_energy
# - sensor.shelly_pro_3em_phase_a_voltage
# - sensor.shelly_pro_3em_total_active_power

# Template for total consumption
template:
  - sensor:
      - name: "Total Power"
        unit_of_measurement: "W"
        state: >
          {{ states('sensor.shelly_pro_3em_phase_a_power')|float +
             states('sensor.shelly_pro_3em_phase_b_power')|float +
             states('sensor.shelly_pro_3em_phase_c_power')|float }}

Buy: Shelly.cloud, Amazon

Why Emporia Vue 3?

Price: ~$200 (with 16 sensors)

Emporia Vue 3 is best for circuit-level monitoring:

✅ Up to 16 individual circuits
✅ Identify power hogs
✅ WiFi + Ethernet
✅ Solar/net-metering support
✅ Can flash to ESPHome (local!)

Disadvantages:

❌ Cloud-dependent by default
❌ Requires DIY for local control
❌ Primarily US market (split-phase)

Local with ESPHome

Flash Emporia Vue for 100% local control:

# emporia-vue3.yaml
esphome:
  name: emporia-vue3

external_components:
  - source: github://digiblur/esphome-vue3@dev
    components:
      - emporia_vue

esp32:
  board: esp32dev
  framework:
    type: esp-idf

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

api:

sensor:
  - platform: emporia_vue
    phases:
      - id: phase_a
        input: "A"
        calibration: 0.022
        power:
          name: "Phase A Power"
        # ... more sensors

Guide: digiblur.com

Buy: Amazon, Emporia Energy

🔧 IoTaWatt - Power User

Price: ~$280

IoTaWatt is the community favorite for advanced users:

Pros	Cons
✅ 14 CT inputs	❌ Expensive
✅ 100% local (no cloud)	❌ Hard to get in Europe
✅ Open source	❌ More complex setup
✅ Very accurate	❌ Requires electrical knowledge
✅ Web interface
✅ Influx/Emoncms export

Home Assistant Integration

# IoTaWatt integrates via REST or MQTT
# HACS: IoTaWatt integration

# Settings → Devices → Add Integration → IoTaWatt
# Enter IoTaWatt IP address

# Entities:
# - sensor.iotawatt_mains
# - sensor.iotawatt_heat_pump
# - sensor.iotawatt_ev_charger
# etc.

Buy: IoTaWatt.com

🔌 Smart Plugs with Energy Monitoring

For single-device monitoring use smart plugs:

Model	Protocol	Max Load	Price ~
Shelly Plug S	WiFi	2500W	$28
Shelly Plus Plug S	WiFi	2500W	$35
Nous A1T	WiFi (Tasmota)	3680W	$14
IKEA TRETAKT	Zigbee	2300W	$14
Aqara Smart Plug	Zigbee	2300W	$21

Combination: Whole + Details

# Best strategy: Main meter + smart plugs

# 1. Shelly 3EM measures total consumption
# 2. Smart plugs on large consumers:
#    - Washing machine
#    - Dryer
#    - Dishwasher
#    - Gaming PC
#    - Refrigerator

# Template: "Other consumption"
template:
  - sensor:
      - name: "Other Power Usage"
        unit_of_measurement: "W"
        state: >
          {% set total = states('sensor.shelly_3em_total_power')|float %}
          {% set washer = states('sensor.washing_machine_power')|float %}
          {% set dryer = states('sensor.dryer_power')|float %}
          {% set fridge = states('sensor.fridge_power')|float %}
          {{ (total - washer - dryer - fridge)|round(1) }}

📱 Home Assistant Energy Dashboard

Configuration

Home Assistant’s Energy Dashboard provides fantastic insights:

Settings → Dashboards → Energy
Electricity grid:
- Grid consumption: Your import sensor
- Return to grid: Your export sensor (if solar)
Solar panels: (optional)
- Solar production sensor
Individual devices:
- Add smart plugs with energy monitoring

Electricity Price Integration

# For dynamic pricing (varies by region)
# Options: Nordpool, Amber Electric, Octopus Energy

# Example: Nordpool for Europe
# HACS → Integrations → Nordpool

nordpool:

# Energy Dashboard:
# - Use entity tracking current price

💰 Automations for Savings

Run appliances when power is cheap

automation:
  - alias: "Start washing machine at low price"
    trigger:
      - platform: numeric_state
        entity_id: sensor.electricity_price
        below: 0.10  # Under $0.10/kWh
    condition:
      - condition: state
        entity_id: input_boolean.washer_waiting
        state: "on"
      - condition: time
        after: "06:00:00"
        before: "22:00:00"
    action:
      - service: switch.turn_on
        entity_id: switch.washing_machine_plug
      - service: notify.mobile_app
        data:
          title: "Washer started"
          message: "Power price is now {{ states('sensor.electricity_price') }}/kWh"

Alert on high power

automation:
  - alias: "Alert on high consumption"
    trigger:
      - platform: numeric_state
        entity_id: sensor.shelly_3em_total_power
        above: 5000  # Over 5 kW
        for:
          minutes: 5
    action:
      - service: notify.mobile_app
        data:
          title: "⚡ High power usage!"
          message: "Your consumption is {{ states('sensor.shelly_3em_total_power') }}W right now"

Find standby consumption

automation:
  - alias: "Report: Night consumption"
    trigger:
      - platform: time
        at: "06:00:00"
    action:
      - service: notify.mobile_app
        data:
          title: "Night usage report"
          message: >
            Last night you used {{
              (states('sensor.shelly_3em_energy_today')|float *
               (6/24))|round(2)
            }} kWh while sleeping.

🛒 Buying Strategy

Starter - Smart Meter (~$50)

1x HomeWizard P1 Meter ($50)
Total: ~$50

Basic - Main Monitoring (~$200)

1x Shelly Pro 3EM ($140)
Electrician installation (~$70)
Total: ~$210

Complete - Per Circuit (~$420)

1x HomeWizard P1 ($50)
1x Emporia Vue 3 16-pack ($200)
4x Shelly smart plugs ($110)
Installation (~$70)
Total: ~$430

Premium - Full Insight (~$700)

1x IoTaWatt + 14 CT ($350)
1x HomeWizard P1 ($50)
6x Shelly smart plugs ($170)
Installation (~$140)
Total: ~$710

🛒 Where to Buy?

Smart Meter Readers

HomeWizard.com - Direct
Amazon - Various options

CT-based Meters

Shelly.cloud - Shelly products
Amazon - Everything
IoTaWatt.com - IoTaWatt

Smart Plugs

IKEA - TRETAKT Zigbee
Amazon - Shelly, Nous

❓ Frequently Asked Questions

Ofte stillede spørgsmål

Does my smart meter have a P1/HAN port?: Most European smart meters installed after 2015 have P1/HAN ports. Check for an RJ12 connector on the meter, or contact your utility company. Older meters typically don't have this port.
What's the difference between CT clamps and P1?: P1 reads data directly from your utility meter - easy but only total consumption. CT clamps physically measure current and can be placed on individual circuits, but require electrical installation.
Do I need an electrician for installation?: For P1 and smart plugs: No. For CT-based meters in your electrical panel: Yes, it's legally required in most places and dangerous without experience. Budget $70-140 for installation.
Can I see consumption per room?: Not directly with main meter. Use either Emporia Vue with CT on each breaker, or smart plugs on larger appliances. Combination of both gives best insight.
How much can I save?: Typically 10-20% by identifying power hogs and shifting consumption to cheap hours. With dynamic electricity rates, savings can be even higher.
Does energy monitoring work with solar panels?: Yes! Bi-directional meters (Shelly 3EM, HomeWizard P1) can measure both import and export. Home Assistant Energy Dashboard shows production, consumption, and net usage.

📚 Next Steps

Dynamic Electricity Prices

Take advantage of cheap hours.

See guide →

Home Assistant

Integrate everything in one system.

Get started →

Last updated: December 2025

Energy Management & Monitoring

📊 Types of Energy Monitoring

Measurement Levels

What Should You Choose?

🇪🇺 Smart Meter Ports - Europe

HomeWizard P1 Meter

Why HomeWizard?

Easy Installation

HA Integration

⚡ Shelly Energy Meters

Shelly Lineup

🏠 Shelly Pro 3EM

Why Shelly Pro 3EM?

Electrical Installation

HA Integration

📈 Emporia Vue 3 - Per Circuit

Why Emporia Vue 3?

Local with ESPHome

🔧 IoTaWatt - Power User

Home Assistant Integration

🔌 Smart Plugs with Energy Monitoring

Combination: Whole + Details

📱 Home Assistant Energy Dashboard

Configuration

Electricity Price Integration

💰 Automations for Savings

Run appliances when power is cheap

Alert on high power

Find standby consumption

🛒 Buying Strategy

Starter - Smart Meter (~$50)

Basic - Main Monitoring (~$200)

Complete - Per Circuit (~$420)

Premium - Full Insight (~$700)

🛒 Where to Buy?

Smart Meter Readers

CT-based Meters

Smart Plugs

❓ Frequently Asked Questions

Ofte stillede spørgsmål

📚 Next Steps

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