Integrating a Mitsubishi Heavy Industries KX-series VRF system (RC-ES1 remotes) into Home Assistant on a budget...has anyone actually done this?

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Hello, i hope this isnt the wrong website to ask for things like that and hopefully the right thread. If not please delete it.

I’m doing a heating retrofit and just had a Mitsubishi Heavy Industries KX-series VRF system quoted: 1x outdoor unit FDC140KXZES1, 7x indoor console units FDFW(22)28KXE6F, each paired with an RC-ES1 wired touch remote. Install is scheduled for the end of September.

My installer quoted smart-home integration as extremely expensive per indoor unit, so it’s not happening unless I DIY it myself. I’d really like to keep the RC-ES1 remotes (not swap them for RC-EX3, which I know has a working community hack).

To save people time, here’s what I’ve already dug into and ruled out for my exact hardware:

  • MHI-AC-Ctrl (GitHub - absalom-muc/MHI-AC-Ctrl: Reads and writes data (e.g. power, mode, fan status etc.) from/to a Mitsubishi Heavy Industries (MHI) air conditioner (AC) via SPI controlled by MQTT · GitHub) — taps the internal SPI bus inside the indoor unit via ESP8266. Confirmed only for SRK/SRC/SRF/DXK residential single-splits, not FD/KX console units.

  • hump-coder/mhi-rc-ex3-esp32 / mhi-rc-ex3-esphome — solid ESPHome climate integration by tapping test points on the remote’s PCB, but explicitly built for the RC-EX3/RC-EXZ3A remote, not RC-ES1.

  • albertvaka/MHI-WifiController — a man-in-the-middle device on the 3-wire bus between remote and indoor unit (no need to open anything). Confirmed only for the older RC-E1 remote and 2004–2006 indoor units.

  • ProtoART CNS-Interface / XY-Interface — their published supported-models lists don’t include the KX/KXE6 series or RC-ES1 (CNS covers SRR/SRF/DXK, XY covers FDTCVH/FDUMVH). I’ve emailed them directly to ask.

  • Intesis/HMS Networks gateways (MH-RC-WMP-1, MH-RC-KNX-1i, 700-series Superlink II gateways) — these are the “official” professional path, but their documented compatible remotes for the KXE6 series are RC-E3/E4/E5/EX1A/EX3/EX3A/RCH-E3 — RC-ES1 doesn’t appear anywhere in their docs either.

So: has anyone actually gotten a KX-series VRF system with RC-ES1 remotes talking to Home Assistant official gateway, reverse-engineered bus tap, anything? Ideally without having to open the indoor units themselves. Happy to share findings back if I get anywhere with ProtoART or Intesis support.

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RC-ES1 is “fairly” new. The other wall thermostats are much older. Most likely it is all compatible since it is the same protocol, but they simply didn’t update their documentation since the Intesis controllers are much older.

I would go for the ProtoART one since it is a much cheaper controller than the Intesis, doing the same thing.

You are talking about Mitsubishi Electric. This is Mitsubishi Heavy Industries. That is a completely different company and the protocols are not compatible.