Light leaks....what is the ACTUAL solution?

Hi!

Your room(s) should be brighter! :S …your first room’s ceiling also looks strange (shadows or AO)… and I don’t understand why your window is so burnt out…
Do you use ANY postprocessing?
If it’s possible I would like to take a look! :wink:

…I did a quick postprocessing on your second pic to brighten it up…