Why is shading particularly important in newly built houses?

It is often argued that shading is especially important in a new building to prevent overheating in summer. Yes, but why actually?

The insulation of a new building works both ways. Whether it is cold or heat – the house takes on the outside temperature much more slowly than an old house with poorer insulation.

And now about the windows themselves. Shouldn't solar energy be able to penetrate faster through poor double glazing than through modern triple glazing?

Why do many say that shading in summer is IMPORTANT ESPECIALLY in new buildings? I would rather think the other way around, a new building is better insulated against heat from outside. Triple-glazed windows with a high U-value keep heat out better than old double-glazed windows?

Quite simple:

If there is no shading, the interior of the house heats up very quickly due to solar radiation through the windows.
In a new building, the heat can only escape slowly and with difficulty (which is also desired in winter).
For this reason, it is more important in a new building than in an old house with poor insulation to provide [aussenliegende Beschattung].
Because once the place is heated up, it stays warm for a very long time.

Simply wrong, because the summer heat protection is precisely not provided at the windows (keyword: solar gain).

Everyone with their new buildings is experiencing this right now... if you didn’t have the shutters down, you just bake...

The U-value of the windows is still approximately 5 times higher than that of the exterior walls, at around 1. So a lot of heat still gets in there. And we are actually experiencing that right now. If we don't have shading, the living room easily reaches 28°C. With shading, we can maintain 24-25°C even at 35°C outside temperature.

Shading is always important. Of course, if the facade has holes and the insulating effect of a mango, it no longer matters about the windows - it gets warm. At night, however, it quickly gets cooler again - which doesn’t matter during summer tropical nights. In new buildings, the heat comes through the windows (or through the constantly open door, where your own and all the neighborhood children want ice cream or need to use the bathroom every 3 minutes)... since everyone (children or not) builds the light-flooded temple of Nice, there is accordingly a lot of heat gain through unshaded windows... and what is inside doesn’t just leave quickly.

Simply wrong, because summer heat protection is precisely not provided at the windows (keyword: solar gain).

Everyone with their new buildings is experiencing this right now...those who didn’t have their shutters down are just suffering...

That's how it is. Therefore, we have professionally installed air conditioning directly fixed in the living room/kitchen, bedroom, and office. I can only recommend it. It costs us about 8000 EUR... but it is definitely worth it.

Best regards, Steffen

PS: yes, the children have to sweat