Warning: This platform has not been exercised against a real exterior heater. Expect to report results.

If you own an IO-Homecontrol terrace or patio heater, please try it and report what happens on the issue tracker: success, silence, or a wrong level are all useful.

Exterior heating (node type 21, exterior_heating) is a heater with a heat level rather than a setpoint. It appears in Home Assistant as a fan: on or off, and a speed from 1 to 100 % that is the heat level. Subtype 58 is on/off, so its fan has no speed. Every exterior heater is sent the main parameter only, without a functional-parameter block, which is valid on any device.

The keys every entity platform shares — name, io_device_id, io_device_type, io_subtype, status_poll_interval, low_power, linked_remotes, home_io_control_id — are documented in the configuration reference, along with the seven diagnostic companion entities.

fan:
  - platform: home_io_control
    name: "Terrace Heater"
    io_device_id: "6F7081"
    io_device_type: "exterior_heating"

  - platform: home_io_control
    name: "Patio Heater On Off"
    io_device_id: "708192"
    io_device_type: "exterior_heating"
    io_subtype: 58

Scan Paired Devices and Discover & Pair print a ready-to-paste fan: block for an exterior heater.

How the heat level maps to the wire

Heat p % is sent as the IO position 100 - p, the same mapping a dimmable light uses. The main parameter is the position times 0x200, so 100 % heat is 0x0000 and off is 0xC800 (VELUX KLF 200 API specification, Table 277).

Setting a speed sends that heat level and turns the heater on.
Turning on without a speed uses the last level the heater was at, else full heat.
Turning off sends 0 % heat. The fan keeps its last level, so the next turn-on returns to it.
A subtype 58 heater is on (full heat) or off.

What the card shows

A command shows the commanded state until the heater's status reply replaces it. The hub reads the heater with the ordinary status request about five seconds after boot and a few seconds after every command. A heater has no movement to wait for, so that one follow-up poll is all a command costs, and a change made at the heater itself shows after the next command or reboot. The fan never restores a saved state at boot; the first status poll decides what it shows.

How the heat level maps to the wire

What the card shows

See also