Replacement windows squeeze in air between two panes of glass, providing a layer between the inside of your home and the weather outside. Thus, replacement windows insulate your home from extremes of both hot and cold. And at the same time reduce your home's energy costs and change its decor.

Replacement windows come in many shapes, sizes, and styles to match your home. Basically, there are four types of replacement windows: (i) replacement windows add light and style to your home; (ii) skylights brighten the room and add an interesting design element; (iii) sliding doors are another form of replacement windows; and (iv) the slider helps you save on energy, especially in summer, because you can leave the screened portion open.

Before you buy replacement windows, you need to decide how you want them to open. Again you have various choices, such as: (a) casement windows with vertical hinges that swing in or out by winding a handle; (b) double or single hung types made of two cases that slide up and down; (c) sliding windows that move horizontally; and (d) plain fixed form windows that don't open at all, but let the light come in.

You also need to see how your replacement windows have been fabricated to make sure they match with the architecture of your home and provide maximum insulation. You can now choose from some recent manufacturing developments like vinyl and fiberglass that are highly insulating.

Vinyl windows are a popular and economical alternative to aluminum, wood, and fiberglass, because they are energy efficient, easy to install, and effortless to maintain. Made from a plastic called polyvinyl chloride, or PVC they provide a superb degree of insulation. Moreover, they require practically no maintenance because their durable surfaces are already stained, finished, and sealed. The exterior casing of vinyl windows doesn't fade or wear under ultraviolet sunlight, making them far more durable than aluminum or wood.

For the purpose of energy efficiency, you can go in for triple-pane windows that have three pieces of glass with layers of air between them. Air absorbs heat and cold much better than glass. You can further reduce air conditioning and heating costs if you replace the air with a gas called argon.

While shopping for replacement windows, visit many showrooms and make sure that the window is 'user friendly'. Try it out to see if it opens and closes with ease. You must remove all your doubts before scheduling an installation. Also, look for certification information from the National Fenestration Rating Council to compare the energy efficiency of each brand and style of window. Don't forget to see the actual warranty before making your purchase and understand all the details.

Replacement windows involve heavy expenditure, so it is important you make an informed and confident decision based on the needs of your house, the kind of windows to be replaced, and your budget constraints.