Components of double glazing



Double Glazing is also known an Insulating Glass or Double-pane.  The Double glazing contains two or three glass-window panes that are separated by gas or vacuum filled space, which is designed to reduce heat transmit across the building cover. The DGU (Double Glazed Unit) fits within a window frame contains seven components that include:

  • A Space Bar: The frame that split the two glass panels and creates a hollow-space. The space bar can be  warm-edge  or aluminium
  • Desiccant: It is a silicon material that is used in the space-bar to dehydrate moisture caught inside the hallow-space.
  • A Primary Seal: The main obstacle to moisture or air migration into the DGU.
  • The Glass: You can find different types of glass, including clear, Low E, Solar Control, Acoustic, Self-Cleaning, Laminated, Toughened, or you can get it in a combination as well.
  • The Cavity or Hallow Space: The gap between the component parts
  • The Secondary Seal: It is a kind of glue that is applied to the main structure, around and the outside edge of the component so that it can hold the rudiments together.
  • The gas filling the hallow-space: It can dry out the air, krypton, argon, or Xenon.

A double glazing window contains four faces:

  • F1 (Face 1): Atmosphere side, and the outer pane.
  • F2 (Face 2): The Cavity Side, and the outer pane.
  • F3 (Face 3): The cavity side, and the inner pane.
  • F4 (Face 4): Room side, and the inner pane.


It is important that specialist types of glass, such as Low E or self-cleaning, be positioned on specific faces within the double glazing window when a window replacement is made. For example:

If you are planning to use special types of glass like Self-cleaning or Low E glasses, then you should know that it is important that these special glasses be positioned on certain faces within the double glazing window, when you want to replace the window. For instance, if you are using Self-cleaning glass, then it must always be placed on the outer pane, with the phase-1 coating.  If you are using the Solar Control Glass, then it should be placed on Face-2 of the double-glazing window. In case, you are using the Low E glass, it should be placed either on the outer-pane or the inner-pane, but the coating must be always on Face-2 or Face-3 of the unit.

Double Glazed Windows: Advantages

The Double glazed window contains two layers of glass and in between the glass; it is sealed with an inert gas. This process generates almost twice the filling as single glazed units. Once you seal the glasses, then the unit gets airtight.

The benefits of double glazed windows include energy cost savings.  The double glazed windows airtight structure creates thermal insulation, which further reduces the flow of outgoing and incoming heat. With these glass windows, less energy will be sued to cool down or heat-up the space and lower your current bills.