These are windows, which are made of two panes of glass separated by a layer of gas or air and then are sealed. Windows that are double-glazed were designed to give a better barrier against the outside temperatures than windows that are single paned. The reason is that the buffer and two layers of glass act like insulators. The glass features a specially coated surface. This surface prevents the heat from entering your home during hot weather and in cold months, it re-radiates the heat. Double glazed windows were originally created for extreme climates. Today they are used in all locations as replacement windows and for new construction.

The double glazed windows that use an inert gas between the windows are a better insulator than the ones with a sealed pocket of air. The gas most often used is argon. This type of gas allows less cold to enter the room and less heat to escape. They have a higher density and offer a better buffer than just air. These windows are made in factories are sealed airtight. This is to eliminate the potential for condensation for form in between the pains and enhance insulation. These windows are also referred to as Insulated Glass Units (IGU’s) and the gap between the two panes of glass can range from 6 mm to 20 mm. The larger the gap the more insulation you will have. The price will vary but normally they cost at least twenty-five percent more than a single glazed window.

Glass used in double glazed windows

• Low emissivity-this is a common selection used in double glazed window. It contains a metallic layer that is virtually invisible in the glass panes. They also use a special coating that comes in different glazes, which will accommodate different climates.

• High solar gain-it is preferred for areas that have very cold winters and cool summers. The reason is that it increases solar or heat gain and reduces heat loss.

• Moderate-solar-gain-this glass that is preferred for areas with mild winters and summers. Without losing light, it will let in a smaller amount of heat.

• Low solar gain-this is for areas with mild to moderate winters and very hot summers. It offers the highest protection from UV rays.


• Increases the value of a home

• Ability to conserve energy

• Reduces energy bills because they keep a home cooler in the summer and warmer in the winter

• Better insulation against noise

• A measure of increased security because there is an extra layer that acts as a barrier against burglars

• They have a high UV coating and will items in the home and people from sun damage

• Has very low maintenance