Add defrost sensor support for Panasonic AC

[willie013]

This PR adds a binary sensor to indicate when the unit is defrosting and exposes it in HA through the defrost sensor.

[willie013]

Disclaimer: I only tested with the CNT integration, since my units works with this connection. The WLAN implementation might require some testing/rework

[mvonweis]

I can confirm that this PR works on a Panasonic NZ35VKE with the CN-CNT connector. We've got -12°C outside right now and the unit is defrosting every 3 hours or so.

[profigriller]

I can confirm this works on CS-Z25XKEW and CS-Z35XKEW. This has been tested on MultiSplit and MonoSplit. Nice :-)
I was using a temperature sensor on the external unit to detect a defrost cycle up to now. This new implemetation is a very valuable enhancement. I use the CNT interface.

EDIT: One comment on the behaviour. For multisplit unit all indoor units report the defrost status no matter if they are in HEAT or OFF mode.

[profigriller]

are we waiting for someone to test this change with the WLAN variant?

[doff-1]

I'm willing to test with the WLAN variant if someone creates a repo I can call in my yaml like I do with this in my yaml:

external_components:
source: github://DomiStyle/esphome-panasonic-ac

[profigriller]

This is how my yaml looks like to include the change

• external_components:
  • source:
    type: git
    url: https://github.com/willie013/esphome-panasonic-ac

[doff-1]

It doesn't work for me.
I think the repo is missing the latest fix for esphome 2026.1.0

[profigriller]

I am still at 2025.11.0
you could temporarily rollback your esphome version
pip3 install -U esphome
Pip3 install esphome==2025.11.0

[profigriller]

I created a fork containing the defrost feature based on 2026.1.0 in case you want to give this a try
https://github.com/profigriller/esphome-panasonic-ac

[doff-1]

Thank you!
I've tried your fork since yesterday (still am).

The defrost status has been "unknown" since I installed it, based on the power draw of the AC it should have been through at least two defrost cycles which has not been reported.

[profigriller]

Then we have a problem. The DEFROST status reports immediately OFF when the esp starts using the CNT interface.
I have no idea about the code change and what to analyze or adjust. This was my 1st fork ever. It would be nice if @willie013 could comment how he found out about the DEFROST status

[ctessels]

I just tried the fork from profigriller because i'm on 2026.2.1.
The defrost sensor reports 'off'. Which makes sense since it's not freezing outside at the moment and the AC hasn't been used today. I'm using the CNT interface on a split unit.
Most likely it will start freezing at the end of next week. I'll check if it reports any defrost cycles.

[mvonweis]

Well... my fork with PR#173 works quite nicely on 2026.1.4. It's been well below -10° for most of January and the ACs has been defrosting regularly, with corresponding power spikes. I have two Panasonics, an NZ35VKE and an NZ25VKE, with identical esphome/DomiStyle setups.

I originally installed the patch on Jan 8th on whatever esphome version was current at that time, and have updated fairly frequently since then. I'm compiling from an up-to-date fork of the DomiStyle master branch with minimum temperature set to 8°C and some of the recent patches applied (PR#173). I can do a proper diff when I get home from work to see if there are any other changes.

By the way, I've also programmed both ACs to use a different defrost mode, using the remote control. This was more than three years ago so I don't recall the details but could dig them up if it's important. It shouldn't affect the defrost status though, it just changes some parameters in the algorithm that determines when it's time to defrost.

[mvonweis]

Sorry, I just realized that the problem is about the CN-WLAN variant. I'm on CN-CNT. Please ignore my previous message... 😳

[paducz]

CN-CNT connector, units CS-Z35XKEW + CU-Z35XKE. Works well. Can we get this merged, please? @DomiStyle