This is an old house with the classical lines of a colonial mansion. The windows are 6 over 6 doublehungs, but their beauty is (was) hidden behind the aluminum storm windows. Now the 'Indow' windows are looking very smart as compared to the aluminum covering over the other windows. The other concern was the need to update our weatherproofing. The current storm windows are decades old and very inefficient in the insulating ability. The Indow windows are performing to our expectations. The installation was very easy. No screws to drill for and drive, no felt pack to insert. Just pop them in and enjoy.