How good are roof windows?

I disagree with . Primarily, we are talking about a spare room/playroom that will get a larger window in the gable. Possibly a partition will be made at some point. I remember your initial house planning with dozens of rooms for all sorts of contingencies ;) Well, you can always partition later, and some light in the front area of the whole room is good anyway. A skylight does what it’s supposed to do: it provides light, keeps the weather out, and if necessary, you can ventilate. Whether the window cleans itself depends on the roof pitch, which I don’t have in mind for your place. I also assume that this anteroom is not used constantly, so that it does not need to be ventilated uncontrollably, allowing rain to get in. What else are we talking about here? Rain can get in through any type of window if it is open. The price of a dormer is not in proportion to your planned benefit. Whether this room will ever be partitioned is questionable. Whether there will ever be a bed underneath is as well. My experience as a child: great star gazing, and when it rains, special knocking sounds that remind of camping holidays. My parents still have those windows from 1978: the wood in front has water stains because we had to use those windows as fully functional for ventilation back then. I think, after over 30 years, a carpenter has worked on them as well. But they are still there – they still provide light and keep the weather out. What more do you want?

Interestingly, many people blame the glass pane for noise during rain, but this is not the case. The main cause of this rattling is rather the outer metal covering of the frames. Manufacturers therefore apply a special coating to the cover plates on the inside, which dampens the noise. Additionally, there are windows on the market with rain sensors, even some that take care of ventilation on a timer. A friend of mine had such modern stuff installed and always talks about it enthusiastically.

Thank you for the discussion so far!

I do not see moisture problems due to leaving it open in our case. Ventilation is primarily the task of the controlled residential ventilation system.

The purpose of one room might perhaps become a children's room for a third child - therefore, not a storage room.

So, my only concern would be moisture with closed windows due to leaks after several years. Hopefully unfounded.

My children's room has a large skylight window that has been sealed for over 30 years - although it sometimes drafts a little. In the new house, we have a really big skylight window, which is also remarkably quiet even during heavy rain.

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Did the double casement windows have shutters?

Ours only had blinds on the inside, which was enough for me for the time I still wanted to live there. Everyone is used to different noises, of course. If you previously lived on a main or federal road or near railway tracks, you might not find the rain on the double casement windows so disturbing. As I said, we had one directly above the bed, and when it rained, I more than once preferred to sleep on the couch, not to mention hail. But there are probably few to no problems with tightness. You also have to consider where you live when it comes to snow. If 10cm of snow falls in the whole year, then that's negligible. However, if you live in the Alps, have snow from December to March, and that is the only window, then it can be quite annoying.