"Windows aren’t exactly the first things that come to mind when talking about insulation. However, the article stresses that they’re responsible for almost one-third of the heat loss a house experiences. Evidently, this loss can be a disadvantage for households especially during winter. Smart homeowners in Chesapeake, Virginia who feel that they’re paying pricey energy bills might want to install multi-paned windows in Chesapeake. Untreated windows allow heat to seep through them, causing major losses in heat and forcing furnaces to use up more energy to make up for the difference. By using enhanced windows of the multi-paned and glazed variety, heat loss can be minimized and heaters will expend less energy as a result. It should also be noted that the article even mentions a tax rebate for households that install these efficient windows, so even more money can be saved through replacing the fixtures."
http://www.beachwindows.com/industry-news/why-it-pays-to-have-your-windows-in-chesapeake-replaced-with-new-ones/