Area Valve Temperature Offset Calibration Blueprint

Automatically calibrate all smart radiator valves (TRVs) in a room using a single external temperature sensor.

🎯 What This Does

Smart radiator valves have internal temperature sensors, but these are often inaccurate because they're mounted directly on the radiator. This blueprint:

• Discovers all thermostats in a chosen area (e.g., "Living Room")
• Compares each valve's internal reading to your accurate external sensor
• Calculates and applies the correct temperature offset automatically
• Skips any thermostats that don't support offset calibration
• Updates continuously to maintain accuracy over time

Real-World Example

• Your external sensor reads: 21.0°C (accurate)
• Valve's internal sensor reads: 23.5°C (too high, near the radiator)
• Blueprint calculates offset: -2.5°C
• Result: Valve now "sees" 21.0°C and heats correctly! 🎉

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📋 Prerequisites

What You Need

1. Smart Radiator Valves with temperature offset support

   • Common brands: Hama, Aqara, Tuya, Zigbee TRVs, Z-Wave TRVs
   • Must expose a number entity for temperature offset (usually named *_temperature_offset or *_local_temperature_offset)

2. External Temperature Sensor in the room

   • Should be accurate and away from radiators
   • Examples: Aqara sensor, Xiaomi sensor, ESP32 sensor, Zigbee temp sensor

3. Home Assistant with areas configured

   • Your valves and sensors must be assigned to areas (Settings → Areas & Zones)

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🚀 Installation

Step 1: Import the Blueprint

Option A: Via URL (Easiest)

1. Copy the blueprint URL from GitHub
2. Go to Settings → Automations & Scenes → Blueprints
3. Click Import Blueprint
4. Paste the URL and click Preview → Import

Option B: Manual

1. Copy the entire blueprint YAML code
2. Create a new file: config/blueprints/automation/area_valve_calibration/calibration.yaml
3. Paste the code and save
4. Restart Home Assistant or reload automations

Step 2: Create an Automation

1. Go to Settings → Automations & Scenes
2. Click Create Automation → Use Blueprint
3. Select Area Valve Temperature Offset Calibration

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⚙️ Configuration

Required Settings

Setting	Description	Example
Area	The room containing your valves	Living Room
External Temperature Sensor	Your accurate room thermometer	sensor.living_room_temperature

Optional Settings (Recommended Defaults)

Setting	Default	Description
Minimum Time Between Updates	300 seconds	How often to recalibrate (prevents excessive updates)
Rounding Step	1.0°C	Offset precision (use 0.5 for half-degree support)
Manual Correction	0.0°C	Fine-tune if valves over/under-heat
Offset Entity Suffix	temperature_offset	Pattern to find offset entities (rarely needs changing)

Understanding Manual Correction

After the blueprint runs for a day, you might notice:

• Room too warm? Set manual correction to +0.2°C to +0.5°C

  • Makes valves think it's warmer → they heat less

• Room too cold? Set manual correction to -0.2°C to -0.5°C

  • Makes valves think it's cooler → they heat more

Start with 0.0°C and adjust in small steps (0.1-0.2°C increments).

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📝 Complete Setup Example

Scenario: Living Room with 3 Radiators

Equipment:

• 3x Hama smart radiator valves
• 1x Aqara temperature sensor (on the wall, away from radiators)
• All assigned to "Living Room" area

Configuration:

Area: Living Room
External Sensor: sensor.aqara_living_room_temperature
Min Interval: 300
Rounding Step: 1.0
Manual Correction: 0.0
Offset Suffix: temperature_offset

What Happens:

1. Blueprint discovers all 3 climate entities in Living Room
2. For each valve, it finds the matching number.*_temperature_offset entity
3. Every 5 minutes (when sensors update), it:
   • Reads Aqara sensor: 20.5°C
   • Reads valve 1 internal: 23.0°C → calculates offset: -2.5°C → applies
   • Reads valve 2 internal: 22.5°C → calculates offset: -2.0°C → applies
   • Reads valve 3 internal: 24.0°C → calculates offset: -3.5°C → applies
4. All valves now heat to maintain accurate 20.5°C room temperature!

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🔍 Troubleshooting

Problem: Automation doesn't trigger

Check:

• ✅ External sensor is updating (check state history)
• ✅ At least 5 minutes passed since last trigger (min_interval)
• ✅ Climate entities have current_temperature attribute

Fix: Look at automation traces (Settings → Automations → [Your Automation] → Traces)

Problem: Some valves aren't calibrated

Check:

• ✅ Valve is assigned to the correct area
• ✅ Valve has a number.*_temperature_offset entity
• ✅ Offset entity is available (not "unavailable" or "unknown")

Fix:

• Go to Developer Tools → States
• Search for your valve's entities
• Confirm the number entity exists and matches the suffix pattern

Problem: Offsets keep changing wildly

Likely causes:

• External sensor is near a heat source (window, door)
• Min interval is too short (increase to 600+ seconds)
• Valve readings are unstable

Fix:

• Move external sensor to a neutral location
• Increase minimum interval to 600-900 seconds
• Wait 24 hours for system to stabilize

Problem: Room still too warm/cold after calibration

Solution: Use manual correction

• Too warm: Set to +0.3°C, wait 12 hours, adjust if needed
• Too cold: Set to -0.3°C, wait 12 hours, adjust if needed

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🧪 Testing Your Setup

Quick Test (5 minutes)

1. Check current readings:

   • Note your external sensor: e.g., 21.0°C
   • Note each valve's reading: e.g., 23.5°C, 22.8°C, etc.

2. Trigger the automation manually:

   • Go to Settings → Automations → [Your Automation]
   • Click Run (top right)

3. Verify offsets updated:

   • Go to Developer Tools → States
   • Search for number.*_temperature_offset
   • Check values changed to match your calculation

4. Wait 30 minutes:

   • Check if valves now report temperatures closer to external sensor
   • (Internal sensors won't match exactly, but should be closer)

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💡 Tips for Best Results

Sensor Placement

• External sensor: Mount on interior wall, chest height, away from radiators, windows, and doors
• Avoid: Direct sunlight, drafts, near electronics that generate heat

Valve Behavior

• New installations: Allow 48 hours for initial calibration to settle
• Seasonal changes: Offsets may need minor adjustments when outdoor temperature changes drastically
• Battery levels: Low batteries can cause erratic valve behavior

Optimization

• Start with default settings (300s interval, 1.0°C rounding, 0.0 manual correction)
• Monitor for 24-48 hours before making adjustments
• Change only one setting at a time to isolate effects
• Document your changes and results

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🔧 Advanced: Multiple Rooms

Create one automation per room:

Living Room:

• Area: Living Room
• Sensor: sensor.living_room_temp

Bedroom:

• Area: Bedroom
• Sensor: sensor.bedroom_temp

Kitchen:

• Area: Kitchen
• Sensor: sensor.kitchen_temp

Each automation independently manages its area's valves.

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📊 How the Math Works

New Offset = External Temp - (Valve Temp - Current Offset) + Manual Correction

Example:

• External sensor: 21.0°C
• Valve reads: 23.5°C
• Current offset: 0°C
• Manual correction: 0°C

Calculation:

New Offset = 21.0 - (23.5 - 0) + 0
           = 21.0 - 23.5
           = -2.5°C

Result: Valve will subtract 2.5°C from its reading, so it "sees" 21.0°C

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🆘 Support

Getting Help

1. Check automation traces for errors
2. Review Home Assistant logs (Settings → System → Logs)
3. Post in Home Assistant Community forums with:
   • Your configuration
   • Automation trace screenshots
   • Error messages from logs

Common Log Messages

• "Skipping entity X: no offset entity found" → Normal for thermostats without offset support
• "Entity unavailable" → Device offline or not responding
• "Rate limited" → Too many updates, increase min_interval

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📜 License

This blueprint is provided as-is under MIT License. Feel free to modify and share!

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🙏 Credits

Based on the original single-valve calibration blueprint, enhanced for multi-valve area support with robust error handling and automatic device discovery.