Question:How does double glazing help insulate a house?
Double glazing means that the window is made of two sheets of glass, which are separated by an air gap.
Glass is a fairly good conductor of heat, so when a single glazed window is in a warm room it will conduct heat through to the cold outside fairly efficiently.
Double glazing reduces heat loss from a house by isolating the cold side of the window from the warm side of the window by putting an air gap in the middle.
In order for heat to leave the house by conduction, the heat energy must be transmitted through the first sheet of glass and then through a layer of air and then through the second sheet of glass.
Air is a very poor conductor of heat because it is a gas and therefore the air gap slows down losses due to conduction.
The size of the air gap in double glazing is kept small, because this prevents convection currents inside the air gap from happening and from reducing the insulation effect.