Old, outdated windows are one of the biggest energy drains on many houses. Replacing your windows for new ones with double pane, energy efficient glass will be a large investment, but it may pay for itself over time in decreased energy bills. Plus, your house will feel more comfortable no matter what the weather is like. Double pane windows insulate a house much better than older, single pane windows. As you'd expect, double pane windows have two sheets of glass sandwiched together in a window frame. They're sometimes referred to as double glazed windows. The air trapped between the panes acts as a buffer, keeping cold or heat from seeping into your home. In some cases, a gas such as argon is sealed between the panes to increase the insulation. These windows are factory sealed in a vinyl o