There are many types of windows, and materials used to make them. Most windows are made out of wood, steel and aluminum. Newer windows are vinyl covered with thermo pane glass. Thermo pane glass is two or more panes of glass with a sealed air space between panes and provides a good resistance to heat and cold. The most popular window types are double and single hung, casement, sliding and awning windows. Older windows can be drafty, leaky and difficult to operate. Window replacement is very expensive. Newer thermo pane installation windows used in the last 15 to 20 years can be prone to seal loss and a cloud or discoloration occurs in between the panes of glass, which can’t be removed. The inspector will look at the age, quality, installation and overall condition of the windows. Sometimes older windows, even though in excellent condition, should be replaced just to improve the insulation quality of the home. One of the most dramatic effects on heating and cooling expenses is to replace old or poor quality windows. The windows need to be installed well and maintained to prevent leaks around the exterior and for good operation. If large windows are poorly installed they will be difficult to operate in the future and the thermo pane seal may fail. Skylights and fixed wall light type windows are inspected carefully for leaks and quality. Skylights installed after a roof has been installed almost always leak! These leaks can cause tremendous damage to the surrounding building materials and go undetected for years.