Humidex Sensor for Home Assistant

A Home Assistant integration that calculates the Humidex index based on your existing temperature and humidity sensors.

What is Humidex?

Humidex (humidity index) is a measure used by Canadian meteorologists to describe how hot and humid air feels to the human body. It combines air temperature and relative humidity into a single number to represent the perceived temperature.

Humidex Comfort Scale

• 20-29°C: Comfortable
• 30-39°C: Slightly uncomfortable
• 40-45°C: Very uncomfortable, avoid physical exertion
• 46°C and above: Dangerous, heat stroke imminent

Features

• ✅ Real-time Humidex index calculation
• ✅ Automatic updates when temperature/humidity changes
• ✅ Support for Celsius and Fahrenheit sensors
• ✅ Optional atmospheric pressure sensor for enhanced precision
• ✅ Dual calculation methods (standard dew point-based and enhanced pressure-corrected)
• ✅ Graphical configuration interface (Config Flow)
• ✅ Multilingual support (French/English)
• ✅ HACS compatible
• ✅ Robust input data validation

Installation

Via HACS (Recommended)

1. Open HACS in Home Assistant
2. Go to "Integrations"
3. Click the three dots in the top right
4. Select "Custom repositories"
5. Add https://github.com/LightD31/humidex-ha as an integration
6. Search for "Humidex Sensor" and install it
7. Restart Home Assistant

Manual Installation

1. Download the files from GitHub
2. Copy the custom_components/humidex_sensor folder to your config/custom_components/ directory
3. Restart Home Assistant

Configuration

Via User Interface

1. Go to Configuration > Integrations
2. Click + Add Integration
3. Search for "Humidex Sensor"
4. Follow the configuration wizard:
   • Name: Custom name for your sensor (optional)
   • Temperature entity: Select your temperature sensor
   • Humidity entity: Select your humidity sensor
   • Pressure entity: Select your atmospheric pressure sensor (optional, for enhanced precision)

Supported Sensors

• Temperature: Any sensor with device_class "temperature" (°C or °F)
• Humidity: Any sensor with device_class "humidity" (%)
• Pressure: Any sensor with device_class "atmospheric_pressure" (hPa/mbar) - Optional for enhanced precision

Usage

Once configured, the Humidex sensor will appear in your entities with:

• State: Humidex index value in °C
• Attributes:
  • temperature_entity: Source temperature entity
  • humidity_entity: Source humidity entity
  • pressure_entity: Source pressure entity (if configured)
  • calculation_method: Method used (standard or enhanced)
  • comfort_level: Comfort level (cold, comfortable, slightly_uncomfortable, very_uncomfortable, dangerous)
  • comfort_description: Comfort description, Localized

Lovelace Example

type: gauge
entity: sensor.humidex
name: Humidex Index
min: 15
max: 50
severity:
  green: 29
  yellow: 39
  red: 45

Calculation Formula

The integration uses the official Environment Canada formula based on dew point temperature:

$$T_{dew} = T - \frac{100 - RH}{5}$$

$$e = 6.11 \times \exp\left[5417.7530 \times \left(\frac{1}{273.15} - \frac{1}{T_{dew} + 273.15}\right)\right]$$

$$\text{Humidex} = T + 0.5555 \times (e - 10)$$

Enhanced Precision with Atmospheric Pressure (Optional)

When a pressure sensor is available, the integration can use a more precise calculation:

$$e_{s} = 6.1078 \times \exp\left(\frac{17.27 \times T}{T + 237.3}\right)$$

$$e = \frac{RH}{100} \times e_{s} \times \frac{P}{1013.25}$$

Where:

• T = temperature in °C
• RH = relative humidity in %
• T_dew = dew point temperature in °C
• e = water vapor pressure in hPa
• P = atmospheric pressure in hPa (optional)
• e_s = saturated vapor pressure

Support

• 🐛 Issues: GitHub Issues

Contributing

Contributions are welcome! Make a pull request or open an issue to discuss improvements.

License

This project is licensed under the MIT License. See the LICENSE file for more details.

Acknowledgments

• Humidex formula based on Environment and Climate Change Canada standards
• Inspired by the Home Assistant community

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