They added these frames because windows didn't fit into the window space, it wasn't even close. Tried to force me to think it was part of the 'job'. caulking job was ugly. not enough foam given so now my daughter's room is freezing cold, had to hire contractors to replace the foam in the windows AGAiN. cost: 1500. Not the best windows, casement was hard to open. Stuck to the edges all the time and had to climb up on the ladder to scrape it clean. but would stick right after a rain or dew.