I was tired of the old windows with the small square vent in my apartment. I could never properly ventilate the apartment, and not much light came through those windows either. On top of that, they were dirty inside, and 30% of the window was taken up by the massive wooden frame, which was completely unnecessary. I reached out to the Oknа group of companies with this problem. In the end, I had neat double-pane windows installed, with two opening modes, and new plastic sills. The house became much brighter, and now there are no issues with ventilation. They also installed a mosquito net, and everything is just perfect now! The Oknа group is exactly what was missing in my renovation!
