This style of windows has movable panels. The frame is formed with one or more panels, the glass in the panels are separated by strips of wood. When there are two pieces of glass in the frame they are called double glazed sash windows. The two panes are filled with air or nontoxic gas between them.

One advantage of these windows will be evident when you get your first energy bill after installing them. The air or gas between the two panes helps to keep the cold air out and the warm air inside your home or business during the winter months. The double glazing creates an insulated barrier of air or gas between the glass which aids in preventing heat from escaping.

During warmer weather you can open both the top and bottom in equal amounts and keep the room fairly comfortable. The warm air from the top of the room will escape out of the top of the window and the opening on the bottom will draw the cooler air in from the outside. That is the beauty of this style of window, being able to slide them vertically in separate grooves providing maximum face opening for ventilation.

If your street is noisy they can help to reduce that problem also. Make sure you buy glass that has a thickness of at least an eighth of an inch. Anything less that than that will not help alleviate the noise problems outside.

Another advantage of have windows like these is security. It is harder for an intruder to break through two pieces of glass than one. Often this is a determining factor in whether they will choose your house or not to break into. They come equipped with a range of security feature like special locking mechanisms to deter intruders.

You should be completely satisfied if you buy double glazed sash windows for your home. They will add a classic look to your home. When these windows were first available everything was made from wood, today they are using plastic for the sashes and frames. The plastic ones are not as pretty and will cost you more if you need to replace the glass down the road.

If you want a company that could repair your sash windows London, you need to consider a sash window restoration company. London has some of the finest companies that could repair windows safe and quick.