I am very happy with the efficiency, the fit, the look, and the partial sound reduction. Indow Windows are a very good product with obvious benefits. Kevel provided very knowledgeable and professional service. A less expensive and easier alternative to replacing old windows -- my Indow Windows were ordered, made, and installed within six weeks! I was very pleased to be able to keep my beautiful original windows (on a house built in 1905) and still upgrade to an energy efficient alternative....Great company. Highly recommend Kevel and Indow Windows.