I purchased 6 windows from them in 2006. All 6 allow a significant amount of air to blow in around them, and the two custom made sized ones leak water when it rains or snows hard from the direction they face. A representative from the company has been out several times to confirm these problems, but they have never sent anyone to repair them.I have repeatedly contacted them over the last 4 years without results. A guarantee is only worth as much as the company is willing to honor it--Wall Side Window's guarantee is worthless. I would recommend that people purchase windows elsewhere.