ᐅ Why is shading especially important in newly constructed houses?

Sebastian79 schrieb:
Grym, just trust people who have built – this "problem" is consistent for everyone...

I do trust them...

I would also understand if someone said: Despite good insulation and triple-glazed windows, solar heat gain in summer remains an issue. Compared to a poorly insulated older building, it is less severe, but measures should still be taken.

What I don’t fully understand is why this should be especially important in new construction. Why shouldn’t it be important precisely in older buildings, but also in new builds?

How do you plan to address that in an older building? You’re not constructing it new...

And it has been explained to you multiple times: more windows and especially better thermal insulation that retains the heat.

You know the U-value calculator, which provides plenty of information about summer thermal protection. It also shows very clearly when the heat has penetrated the material.

Sebastian79 schrieb:
especially higher thermal insulation that retains heat.

I wouldn’t agree with that. It doesn’t make physical sense to me. Heat leaves (or enters, if desired) much faster through air exchange by several orders of magnitude. Just compare the heat transfer through the specific thermal conductivity of the facade versus the convective heat transfer caused by air movement.

I don’t need to do any calculations here; I rely on practical experience.

You can look at it from any angle... The fact is: Nowadays, houses are built to keep the heat inside... and always.

Grym schrieb:
What I don’t quite understand is why this should be especially important for new builds. Why wouldn’t it be just as important for older buildings, and why is it also important for new buildings?

- Passive houses (new builds) have large south-facing windows to capture heat during winter. Even with standard new homes, there seems to be a trend toward larger windows, which was not common in the past.
- Insulation in terms of U-value mainly accounts for convective heat transfer, but not radiation. Regarding heat loss, radiation doesn’t matter much because surface temperatures are too low. When it comes to solar radiation, however, the opposite applies – the problem is largely radiation, meaning modern windows offer almost no insulation in this respect.
- To reduce radiation, windows can be coated or tinted, but as mentioned above for passive houses, this would reduce light transmission as well.

That’s why shading is necessary to prevent overheating in summer.

By the way: Older attic apartments tend to get very warm in summer (above 30°C (86°F), even at 10 p.m.). Ground floor apartments are much better protected (thick walls, trees in front of the house, etc.). And apartments in the backyard on the ground floor rarely get warmer than about 20°C (68°F).