Warm bedroom in the house with ventilation including heat recovery

I am really looking forward to that - quietly, I hope that the massive construction pays off. However, I already found out how important shading is back in March.. we have 9 sqm of windows facing south in the living room - in the room it was about 3°C warmer in the evening than anywhere else (which was quite cozy - but well, it was also cold outside) Interestingly, this then quickly equalized again.

I also believe that the 5 to 10k for air conditioning in the living room and bedroom in a new build are very, very well invested. Two summer days at 40 degrees and the room temperatures become unbearable.

I also rely on the solid construction and roller shutters. Our neighbors with exactly the same technology (same company, just a different house type) reported comfortable temperatures to us. Of course, you can't expect 15°C inside the house. An air conditioner is of course a very nice thing. The only pity is that it can't be directly coupled with the ventilation system (condensation...). I don't know this split technology. Otherwise, we would have definitely had it prepared.

We have also built solidly. Once the house has heated up after a certain time, it takes a while to cool it down. The method from definitely helps. In summer, you could also open the upper windows completely overnight. Of course, only where they are inaccessible from the outside due to the risk of burglary. But best only shortly before going to bed, as the temperatures in high summer become comfortable only late at night. Logically, the windows should then be closed early in the morning.

The second tip "shading" has already been mentioned. This definitely helps. However, one should not expect huge temperature differences. But 1 or 2 degrees always work.

To what extent there is a difference between solid construction and prefabricated buildings, I cannot say, as I have no comparison.

So we always run our controlled residential ventilation system (Zehnder Comfoair 350) on low setting during the day (not away, but setting 1). At night when sleeping, at 2 or 3 o’clock it switches to medium setting. You don’t notice this while sleeping, and the bedroom (including dressing room, almost 30m²) always has sufficient oxygen. In the morning, we air out briefly and that’s it. In summer, when it’s really hot, we set the controlled residential ventilation system to away during the day and also close the shutters in the bedroom, then only switch the controlled residential ventilation system to setting 1 when we go to bed, and at night it switches back to 2 until about 7 or 8 a.m., as long as it’s still quite "cool" outside. This way, we achieve the best results for us...

Can you explain the split in more detail or do you have sources on this? I have already searched online, but the results were unfortunately incomprehensible to me.

I assume this refers to the classic split air conditioners. There is an outdoor unit which is connected to the indoor unit by 2 refrigerant lines.