The idea of my window replacement gained focus only after my kitchen window started to warp last this year and had almost become unable to close them. SO I though why not replace my windows on the whole. I was looking for window replacement and did some R&D. I then happened to read an article about energy efficient door & windows that keep the rooms warm in winter and cool in summer. I am thinking of hiring a window replacement service who deals with energy efficient windows in Toronto. I think its pretty cool idea to use these kind of windows. What could be the average cost of replacing windows with energy efficient windows? What are your opinion. Should I switch to the energy saving ones?