Double Pane Windows
Nearly all new construction and replacement windows sold today are double pane windows. Let's go through some of the basics behind what they are, explain a little about the price structure and make some recommendations as to the best options out there for consumers at several different price points.
A double pane window uses two panes of glass to create a more energy efficient window. The two panes of glass are part of the insulated glass unit, which is then surrounded by the sill and frame. The insulated glass unit has the two panes of glass that are separated by a gas fill and spacer system. Good seals and glazing make the unit air tight. Much of the glass used today is a low-e glass that uses an exterior coating to help reflect the heat, while allowing the light to pass through. The dual pane system is much more energy efficient than the single pane windows of the past because the two sheets of glass greatly reduce the amount of heat and/or cold that can transfer from the interior to the exterior pane or vice versa.
Because most windows today are double paned, there is a huge price range that's dependent on a host of factors (explore this in more depth on double pane prices). The most cost determinant is the frame material, with vinyl being the least expensive, fiberglass being the mid range and wood clad being the most expensive. Other price determinants include the model, size, glass package, hardware, as well as the other add ons and available upgrades.
Mid range recommendations are vinyl, fiberglass and composite windows that will run $750 or less when they are fully installed.