🌀 HRV Card

A custom Home Assistant Lovelace card for visualizing Heat Recovery Ventilation (HRV) systems with dynamic temperature flow gradients.

✨ Features

• 🌡️ Real-time HRV temperature visualization - Displays outdoor, supply, extract, and exhaust temperatures
• 🎨 Dynamic color gradients - Cold-to-warm flow mapping with smooth color transitions
• 🏠 Native Home Assistant integration - Seamless card integration with HA themes
• 📱 Responsive SVG-based visualization - Scales beautifully on all devices
• ⚡ Lightweight and fast - Built with Lit for optimal performance
• 🔧 Customizable sensor display - Show additional sensors with status indicators

📸 Preview

📦 Installation

🟡 HACS (Recommended)

1. Open HACS → Frontend
2. Click ⋮ → Custom repositories
3. Add this repository: https://github.com/CodedCactus/hrv-card
4. Select category: Lovelace
5. Install HRV Card
6. Restart Home Assistant

🔧 Manual Installation

1. Download hrv-card.js from the latest release

2. Copy it to your Home Assistant's www directory:

   /config/www/hrv-card.js
   

3. Add the resource to your Home Assistant configuration:

   resources:
     - url: /local/hrv-card.js
       type: module

4. Restart Home Assistant

🧩 Usage

Add via UI Editor

1. Go to your dashboard in edit mode
2. Click Add Card
3. Search for and select HRV Card
4. Configure the required temperature sensors
5. Add optional sensors for additional status display

YAML Configuration

type: custom:hrv-card
title: HRV System
outdoor_temp: sensor.outdoor_temperature
supply_temp: sensor.hrv_supply_temperature
extract_temp: sensor.hrv_extract_temperature
exhaust_temp: sensor.hrv_exhaust_temperature
supply_flow: sensor.hrv_supply_flow
exhaust_flow: sensor.hrv_exhaust_flow
sensors:
  - entity: binary_sensor.hrv_bypass
    label: Bypass
  - entity: binary_sensor.hrv_pre_heater_status
    label: Heater
  - entity: sensor.hrv_exhaust_flow_rate
    label: Flow
    unit: m³/h
  - entity: sensor.hrv_exhaust_fan_duty_cycle
    label: Duty
    unit: "%"

⚙️ Configuration Options

Option	Required	Type	Description
title	No	string	Card title (defaults to "HRV System")
outdoor_temp	Yes	string	Entity ID for outdoor temperature sensor
supply_temp	Yes	string	Entity ID for supply air temperature sensor
extract_temp	Yes	string	Entity ID for extract air temperature sensor
exhaust_temp	Yes	string	Entity ID for exhaust air temperature sensor
supply_flow	No	string	Entity ID for supply air flow sensor
exhaust_flow	No	string	Entity ID for exhaust air flow sensor
sensors	No	array	Array of additional sensors to display

Sensor Configuration

Each sensor in the sensors array supports:

Option	Required	Type	Description
entity	Yes	string	Entity ID of the sensor
label	No	string	Display label (defaults to entity name)
format	No	string	Display format: "binary" or "text" (auto-detected)
unit	No	string	Unit to display (auto-detected from entity)

🔧 Development

Prerequisites

• Node.js (v16 or higher)
• npm or yarn

Setup

# Clone the repository
git clone https://github.com/CodedCactus/hrv-card.git
cd hrv-card

# Install dependencies
npm install

Development Commands

# Start development server
npm run dev

# Build for production
npm run build

# Build and watch for changes
npm run build:watch

# Preview production build
npm run preview

# Type checking
npm run typecheck

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.