To keep your home warmer of a winter and cooler of a summer, you need to look into having energy efficient upvc double glazed windows installed.
To get this insulating effect the window glass itself needs to be insulated to do this they start with two panes of glass instead of one and then they leave a space between the two panes which contains a layer of air(or argon gas which is more inert) which gives it the insulating effect. This causes it not to conduct heat very well, so that the heat stays inside or outside depending on what time of the year it is.
Basically your two choices for double glazing is either a factory sealed unit that replaces your window or what is referred to as secondary glazing which is similar to storm windows in the way they work. The factory sealed units would be the better choice.
Upvc which is what the frames are made of is a heavy plastic looking material similar to a fiberglass. This material is a poor conductor of heat so it makes a good insulator to help keep the heat in. it is also a good noise insulator helping to keep the noise out of your home.
Upvc is used more and more in the manufacturing of windows it is mostly an economical move as wood becomes a more expensive material to use. It is also easier to maintain than either aluminum or wood framed windows. Upvc does not need to be painted, just a quick clean up with soap and water and maybe a little oil on the locks and hinges and maintenance is done.
uPVC Windows have many environmental pluses, besides saving energy by being more efficient they will last longer thus not having to be replaced as often, and if you do have a problem with wear it is probably going to be in the latch or hinge which can both usually be replaced without replacing the entire window. And if you do have to replace the window the upvc material is recyclable.
Some people don’t believe that a uPVC Window is as attractive as a comparable wooden window, but with the available choices in both color and style it would be a hard choice to make. And if you still think that wood looks better you can get upvc in a raised grain wood finish that looks like wood. They can be obtained in just about all styles from a simple sash or casement windows to bay windows or maybe a complete upvc conservatory or sunrooms.
For energy efficiency and plain cost savings you should give upvc windows a second look when it comes time to replace those house windows.