Hi, I have a question about the normal amount of ´Friskluftventils´that should be installed in a house. We bought an old house, around 150m2, that has been completely modernised and "etterisolert". But no ventilation was installed (apart from bathroom electric ventil and an electric kitchen ventil), and the new windows don't have ventilations on them either. So the air especially upstairs can feel heavy. 
Is it normal to have a friskluftsventil in all the bedrooms, loft, living room etc, not every room?
Tricky to find out what is the norm! Feel free to answer in Norwegian, is just easier for me to write in English!