So, we don't have a separate heater for the bathroom, but even refrained from the electric radiator to make room for a cabinet. We have never felt the need to heat there additionally.
How and where do you recommend the infrared heater?
In the bathroom for occasional quick heating and in combination with a heat pump. The alternatives, if higher temperatures are desired permanently in the bathroom, are: a) to equip the bathroom with a lot of water-bearing heating surfaces (walls/ceiling) and possibly insulate the bathroom internally against cold rooms b) to run the heat pump permanently at higher temperatures and thus less efficiently just because of the bathroom If you don’t take care of it yourself, then b) is the normal case. We are satisfied with a permanent 21° in the bathroom and for that a very dense coverage of the floor without additional heating surfaces was sufficient for us. To allow higher temperatures with the baby, we installed the electric heater. We have used it 2-3 times a year now, it also works without it. With infrared heating it feels warm faster. With normal electric heating we have to start heating 30-60 minutes earlier for it to have some effect.
Just to roughly understand this... From the moment I want a room to have a higher temperature, I have to set the entire heat pump higher and then the whole thing becomes inefficient?