If you are looking to replace windows in your home, consider whether you need to replace only the glass, or the frames and the whole mechanism. Windows on older houses often have wooden frames that have changed in shape over time, and if your windows are hard to open and close, you will likely need all-new windows.

In general, the most energy-efficient windows are those that have the best insulated glass unit, although the type of frame and the quality of the seal are also influencing factors. For residential applications, "low-e" double-pane windows with a coating to retain heat in cold weather and keep it out in summer are typically a standard option. The sealant that keeps air between the panes must be secure. Panes with a larger air space between them offer superior insulation. Triple-pane windows offer even better insulation, but are more expensive.

It is important to speak with several sales representatives from different companies prior to purchasing new windows in order to compare the different prices and products they have to offer. This will enable you to get the right product to meet your needs.

Windows should come with a warranty of at least 10 years. Be sure you choose windows that comply with local codes, and look for the ENERGY STAR(R) label.