Well, I took slightly another path with this. After some searching I thought it would be easier to just buy a Broadlink RM Pro, which then sends the commands for me, which works perfectly. Now I’m looking into programming a ESP to do that, instead of a Broadlink, because they’re not cheap. I’ll keep this thread updated if I do so.
Protip: The Broadlink RM Pro (V2) has a temperature sensor in it, which is really nice. V3 hasn’t the sensor anymore.
Trying to figure that out myself.
IRRemoteESP8266 Library works perfectly.
Commands are being read and sent easily.
I am trying to figure out the best way to create a climate component in HA.
(with the added feature of parsing IR signals received from manual remote and changing state of climate entitiy in H)
Also, do have a look at these https://github.com/arendst/Sonoff-Tasmota/wiki/YTF-IR-Bridge
(Just bought one for 10$ at gearbest) (has all the hardware and we can just flash firmware as it uses ESP8266)
(Will update when I receive it next week maybe)
Ooooh, that’s neat. You just saved me a couple hundred bucks! Will definitively look into that, instead of Broadlink.
For the climate component, I’m afraid that someone needs to create its own custom_component, at least for now. If it turns out to work great, it might go into the official components.
As soon as I get some of these YTF IR Bridges, I’ll try to make a custom_component. I’m somewhat familiar with python, so I think I can do this. But if someone manages to get one working before me, I would be very happy 
I have not tried to create a new component yet, and in this case I think I will try to program the script for generating LG-codes in Arduino and use the Climate MQTT component in stead of creating a new one. Just have to learn some Arduino first 
Also looked into Broadlink, but it does not have the nerd factor I want 