# New Vaillant Arotherm+ V2 RS485 **URL:** \ **Category:** Heatpump\ **Tags:** vaillant\ **Created:** [5 October 2026 17:51 UTC](https://community.openenergymonitor.org/t/new-vaillant-arotherm-v2-rs485/30410 "2026-10-05T17:51:11Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![glyn.hudson](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/glyn.hudson/32/35003_2.png) [@glyn.hudson](https://community.openenergymonitor.org/u/glyn.hudson)\ **Post date:** [5 October 2026 17:51 UTC](https://community.openenergymonitor.org/t/new-vaillant-arotherm-v2-rs485/30410/1 "2026-10-05T17:51:11Z")
Interesting, it looks like Vaillant has moved to using RS485 instead of eBUS between the outdoor unit and indoor controller on the New aroTHERM+. Someone has already decoded it and integrated it with Home Assistant 🤓 Thanks to @ectoplasmosis for posting about this on this [Vaillant Arotherm+ V1 vs V2](https://community.openenergymonitor.org/t/vaillant-arotherm-v1-vs-v2/30294) thread. I think this is significant enough to merit its own thread! > **[GitHub - thoutenbos/esphome-arotherm-modbus: ESPHome Modbus reader for Vaillant aroTHERM...](https://github.com/thoutenbos/esphome-arotherm-modbus)** > > ESPHome Modbus reader for Vaillant aroTHERM heatpumps This is good news for geeky owners who enjoy logging data from the heat pump. RS485 is much easier to interface with using low cost readily available hardware. It was possible to interface with eBUS, but it’s a lot more complicated. This will probably also make it easier for 3rd party optimisers e.g Homely, Havenwise and Passive to support Vaillant via a local connection that doesn’t require the Internet. Unfortunately, there’s no evidence they have improved the accuracy of the onboard monitoring data. Currently, it looks like only some of the read-only metrics of the RS485 interface has been decoded. I’m guessing that control via RS485 should be possible…