Nibe, Stiebel Eltron, IVT, Thermia, Vaillant, Daikin, IME, Hoval, Grubmann, Hitachi, Atlantic/Fujitsu, BDR Thermea, Mitsubishi Electric, I could probably find m

Nibe, Stiebel Eltron, IVT, Thermia, Vaillant, Daikin, IME, Hoval, Grubmann, Hitachi, Atlantic/Fujitsu, BDR Thermea, Mitsubishi Electric, I could probably find many more. Some are probably local to Central Europe, but that only reinforces my point.