Window trickle ventilators - holes are drilled with the window body, with external and inside covers more than the holes. A cheap but visually intrusive technique, with poorer Power performance than other solutions. But before you decide to dedicate, It can be value comparing the soundproofing credentials of substantial spec https://charlesd713fbx0.blogars.com/33694850/how-much-to-install-secondary-glazing-fundamentals-explained