Newly built apartment (KfW-55) cannot be cooled, always at least 25 °

Not so bad at all because of the cool nights. The terrace slabs often only become warm to the touch around noon. On the southeast side, I often closed the windows already at 7 or 8 on the weekend because warm air came in, the north side only around 10/11 o’clock. In the evening, it also gets cooler there much earlier. You can definitely notice a difference between the weekend and weekdays. On weekdays, when no one is there during the day, it’s usually around 20 degrees; on weekends it tends to go towards 23 degrees. It was really intense in the office. 70s building, south side. But so shaded by trees that hardly any sun gets in. In addition, the almost cold nights up there. On the radio they talk about a heatwave and we wore jackets. We’ve never done that before.

I'm doing something wrong. I have my computer on at night, it keeps getting warmer even though the window is wide open. Don't you have any power guzzlers that generate heat? The insulated cabin doesn't let anything through. Opening the windows only helps until the morning, then it gets too hot in the office again because of the waste heat from computers and monitors. Without air conditioning, you'll go crazy in there.

We have a monolithically built KFW 55 house (filled bricks) and see a lot of glass on the south side. Does the ventilation system have a bypass? Our ventilation system is set in summer so that it is turned off during the day and only runs at night, and at a level just low enough not to be disturbing noise-wise. At six in the morning it then runs at full power for three hours (400 cbm/h). The bypass is activated during this time, so the air is not drawn through the heat recovery module. At the same time, in the morning when I get up (06:00), I open all the windows and ensure plenty of draft until I leave the house at half past seven. The windows on the south side are completely shaded during the day. What plays a significant role: many interior walls are made of sand-lime brick (for structural reasons) and they buffer quite well.

We do have a split air conditioning system, but it is used extremely rarely. However, we have already had periods when it was clearly over 30 degrees outside during the day and did not go below 25 degrees at night. Then we ran the air conditioning fully during the day, but never had more than 22 degrees in the house at night, which was probably also due to the sand-lime brick walls inside that radiated the coolness of the air conditioning for a long time.

What might also have an effect: we live directly on the edge of the forest and have a stream behind the garden. You can feel very clearly in the evening how the cool air drifts over from the forest. When we still lived in the city center, we did not have such "mild breezes."

I'm doing something wrong. I have my computer on at night, it keeps getting warmer even though the window is wide open. Don't you have any power guzzlers that generate heat? The insulated hut doesn't let anything through. Opening the windows only helps until the morning, then the office room gets too hot again because of the waste heat from computers and monitors. Without air conditioning, you'll break down there.

Don't underestimate what computers need. With monitors, etc., you're quickly at 500W and up or in the range of the lowest setting of a fan heater. If it has to run continuously, it really belongs in a proper server room.

Do you mean the office? It’s a building from the 70s with trees almost up to the building. So far, we have sweated at some point during every heatwave. This year, I suspect it’s simply due to the relatively cool temperatures at night.

I think the key point is to get the heat out of the buildings at night and let in as little as possible during the day, regardless of energy standards or building materials.

Don't underestimate what such computers need. With monitors, etc., you're quickly at 500W or more, roughly the lowest setting of a fan heater. If it has to run continuously, it really belongs in a proper server room

The computer has a 750 watt power supply but usually only needs about 500 watts, as you yourself estimated. I unfortunately can't do without 144 frames to stay at the top in the esports ranking. That already produces quite a bit of waste heat after a few hours; the drywall walls don't absorb any more and it simply gets hot. No matter how much I ventilate at night, it only lasts a few hours, then it becomes unpleasant. A server cabinet in the basement is not an option. 1. because I don't have a basement 2. because a DisplayPort cable is not 20 meters long 3. because it's not a server but a normal tower So none of that helps me :>