Is it stuffy at home when the windows are closed? Is it cold and noisy when the windows are opened? Yes! – This is the answer of those who have not yet installed window filters. The number of plastic windows’ owners (our potential customers) is growing every day. It means that the number of people who suffer from the effects of the tightness of such windows (stuffiness, frequent illnesses and malaise, allergies) and all the inconveniences associated with the rooms’ airing – street noise, dust and drafts is also growing.