I have a Mitsubishi heat pump and a Fujitsu heat pump. Neither one came with Wifi or Smart controlls installed — just a IR remote.
I could add them to my Home Assistant network of smart devices if I spent $300 – $400 on a control unit.
Alternatively I can get an universal IR blaster and hook that up to my network. These IR blasters can learn and mimic the signal generated by the remote control unit that comes with the heat pumps.
Seems like a large number of Home Assistant enthusists have had good luck using the BroadLink brand of IR blasters to control everything from TVs, to ceiling fans and mini splits.
You’ll need one of these devices in each room as like with the remote, it will need a direct line of sight to from the blaster to the appliance.
