ESPHome / Helios KWL

ESPHome integration for Helios KWL via RS485.

Of course, it all makes sense if integrated with the amazing Home Assistant:

Introduction

I've had a Helios KWL EC 500 R since 2012. Back then, I looked into getting the KNX module to hook it up to my home automation, but the price was ridiculous. So, after all this time, I decided to just do it myself. I got an RS485/UART adapter, sniffed the data packets, and actually found the protocol documentation online. I'm powering an ESP32 from the KWL's 24V using a BEC.

Newer Helios units have Ethernet built-in, making integration much easier. But if you've got an older model, this is for you.

I've only programmed the features I use and need, but you could definitely add more.

Wiring diagram

Installation

Check out the helios-kwl.yaml file. This is an ESPHome external component you can easily add to your setup. The best way to get it is using Git:

external_components:
  - source:
      type: git
      url: https://github.com/lostcontrol/esphome-helios-kwl/
      ref: 2025.3.1

Disclaimer

As usual, I decline all responsibility if you break your Helios KWL (or anything else actually).

Shopping list

These are examples of items required for this project. You will also need (silicone) wires and heat shrink tubing.

• RS485 adapter: https://www.aliexpress.com/item/32889414931.html
• Wemos D1 Mini ESP32: https://www.aliexpress.com/item/32815738795.html (select D1 MINI ESP32)
• BEC 5V (input 24V): https://www.aliexpress.com/item/1865193146.html

Links

• Example datagrams: helios-kwl.txt
• Protocol: https://wiki.fhem.de/w/images/7/7e/Digit_protocol_english_RS485.pdf