Triple Glazing Construction

Triple glazing is being hailed for the benefits it provides in insulation and noise reduction; this has led to more interest in the product in the UK. Where once it was used only in colder climate countries, it is now becoming more extensive in use across Britain. A lot of the benefits of the product come from triple glazing construction, so basically the way it is designed and built is what gives it the properties it has.


Triple glazing construction goes much further than just assembling three sheets of glass in a frame and although it may look fairly simple on our home windows there is a lot of work that goes into making it what it is.


Firstly is the gap between the sheets of glass. To maximise the much important insulating properties the gap must be exactly right. If the gap between the sheets of glass is too small then the result is radiant heat loss; too wide of a gap will create gas currents which will lead to convention current heat losses and defeat the main objective of triple glazed windows. An optimum gap is usually around 16 mm. The gap itself is not only a big part in triple glazing construction but is what provides the insulation. Air inside the gap is a good insulator but inserting a special gas is known to have more benefit. The reason is that an inert gas has lower thermal conductivity.  Argon is the gas most commonly used as it is produced cheaply and provides around 33% more insulation than air. Some high specification triple glazing units may use Krypton which provides 50% more insulation than air.


The inner, and sometimes, middle layers of glass will be coated to allow sunlight through the window and prevent it from escaping. The coated glass is known “K-glass” and is made up of a low emissivity product containing a thin layer of metal which is painted either directly onto the glass or onto plastic sheeting which is then attached to the glass each method has the same results. The layer of metal used is usually made up of any of the following:

  • Gold
  • Silver
  • Copper
  • Rod-oxide
  • Indium-oxide


A big key in triple glazing construction is the frame; the frame is what holds everything together and is essential in the structural integrity of the window.  Making sure that the frame is rigid yet workable is hugely important as any twisting may cause the glass to shatter.

Double glazing is usually seen with PVC frames and some triple glazing units can also use this material however a more common triple glazing frame is wooden. Triple glazing construction is commonly done in cold climate countries where wood is relatively cheap yet provides great insulation.


Spacers are what are used to separate each sheet of glass; spacers are made from glass fibre which replaced the once used metal spacers which were found to reduce the efficiency of the sealed unit and increased condensation.