ᐅ Gaps in the exterior sealing of the windows

Hello

There are cutouts in the exterior seals of all the windows, possibly made by the previous owner. I’ve attached a photo. The cutouts are always located at the top.

Does anyone know what these are for?

Thanks for your answers

It looks like a makeshift forced ventilation system.
There may have been previous issues with condensation on the windows or mold.
It could also have been installed by the construction company as part of defect repairs.

We have a central ventilation system here. However, I have never heard that such openings would be required for it.

Me neither,
maybe that was before the controlled residential ventilation system feature,
in any case, it was made as a temporary solution.
Does it let heat or cold in, causing your heating costs to be too high?

If there is only a horizontal opening of about 10cm (5 inches) in the sealing at the top of the outer frame, this is a common pressure equalization feature often found in uPVC windows.

What is the purpose of pressure equalization (or whatever term is used)?

• Primarily: It improves resistance to driving rain. Pressure equalization (regardless of how it is implemented) prevents negative pressure from forming in the water drainage chamber of the frame during strong wind, storms, or heavy rain, which would otherwise hinder or block water from draining through the lower drainage slots.
• Secondarily: Moisture in the rebate (wherever it comes from) dries out somewhat faster and better.

profil65 schrieb:

If there is only a roughly 10cm (4 inches) horizontal opening in the outer sash frame at the top in the seal, this is a common pressure equalization feature often found in plastic windows.

The window has two seals. One that is still visible from the outside when the window is closed, and one in the middle of the frame. The outer seal appears to be somewhat thicker and more durable than the one in the frame. Only the outer seal has the cut parallel to the frame, about 7cm (3 inches) long.