Meet Ramses-II
I already had HomeAssistant running at home. Using so-called Integrations you can link various ‘smart’ hardware brands to his home automation system.
HV Integrations for HVAC?
Our HRV fans in the bathroom, bedroom and living room come with an (expensive €100) wireless RF switch. But wouldn’t it be useful to switch them on at certain times, e.g. when you turn on the light in the toilet, or in the morning after getting up on high for an hour?
The manufacturers did not provide any technical information about how the switches “talk” to the fans. On the contrary, they prefer not to have you touch their default settings for fear that complaints will arise. And they want to make money from their “knowledge” by shielding it and only allow professional mechanics to access this information. And they don’t like to share that info either (if they are allowed to do so at all).
Not for ClimaRad
So I opened my ClimaRad HRU - which did not come with a remote control - myself and found a circuit board with an antenna there. Through the stickers I learned that it was an RF antenna and that the print was produced by [Airios] in Holland.
A phone call to Airios didn’t help: “You must contact ClimaRad”. Airios appears to be originally the consumer branch of Honeywell/Resideo.
Meet Ramses RF
And with that info I ended up with the open source HA integration Ramses RF, written in python by David Bonnes. From 2021 onwards, he and Peter Price figured out the messages they received with an 868MHz antenna (Ramses-II protocol). They developed the first hardware and software to control heating and DHW (hot tap water) as (evohome; HEAT). Dutch users supplemented the code to also control ventilation (Itho, Orcon, Nuaire; HVAC).
But our fans and heat recovery units (NL: WTW, EN: HRU for heat recovery unit) from Vasco and ClimaRad did not work with Ramses RF at the time, so I started writing extra code for that. When that code worked well here in the house, I asked David if he wanted to include the code in a new version that all users can install. But he was concerned that my changes could cause problems with other users. He also indicated that his work meant that he had too little time to keep Ramses RF up-to-date and wrote in the repository that he wanted to transfer everything to a new administrator. After 4 months, I took over that task from David in mid-2025. Due to announced changes in HomeAssistant, the Ramses RF integration would no longer work by the end of 2025, so those became my new priorities:
- Blocking file IO during startup
- Outdated (non) entity schemas
- 2026 is dedicated to overhaul the foundation of the ramses_rf back-end
Links
- HA User Forum: Ramses RF thread
- Repo lib: https://github.com/ramses-rf/ramses_rf
- Repo integration: https://github.com/ramses-rf/ramses_cc
- Wiki: https://github.com/ramses-rf/ramses_cc/wiki
- Pypi: https://pypi.org/project/ramses-rf/
pyairios
Unfortunately, I also discovered that I could not control my ClimaRad Ventura HRU with Ramses RF (HA can read it, but you can’t connect a remote to it).
But Samuel Cabrero from Spain had just released a solution at the beginning of 2025: using an Airios RF Bridge with the pyairios library and airios HA-integration; Search for “airios + ramses”. See:
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