Internorm window installation

Triple Glazing for Windows and Doors

Triple Glazing for windows and doors is a great way to reduce the heating costs of your home as well as helping the environment. If you have aspirations to create a passiv haus or passive house building or improve the carbon footprint of your current home triple glazing will make an immediate difference over single or double glazed windows and/or doors.

We have a range of triple glazing options and most of our product range can be supplied in triple glazing as an optional alternative to double glazing. From time to time we have special offers on free upgrades to triple glazing on certain ranges so its worth following us on Twitter and checking our blog for the latest news.

If you would like more information on triple glazing, including an approximate idea of the energy saving benefits, we have a number of examples in our showroom of triple glazed products. In addition we have a demonstration machine which provides a live experience of the capabilities of triple glazing to keep warmth indoors.


IGU - Insulating Glass Unit

Uw - whole window U-value for a window of standard size and configuration, calculated in accordance with BS EN 673

Uf - U-value of the window/door framing material calculated in accordance with BS EN EN ISO 10077 Parts 1+2

Ug - centre pane U-value of the IGU calculated in accordance with BS EN673.

WER - Window Energy Rating scheme operated by British Fenestration Rating Council (BFRC) of similar bodies.

DSER - Doorset Energy Rating scheme operated by British Fenestration Rating Council (BFRC) of similar bodies.

Thermal Performance

Thermal performance of installed windows can be expressed as U-value (Uw - whole window) or WER. When calculating a WER value the g-value is considered to identify the benefit of solar gain through the glazed unit. Air leakage is also considered when calculating the overall value. Choosing a triple glazed pane over double glazing does not always mean a higher overall U-value. The table below demonstrates triple glazing must be correctly specified in order for it to result in a better U value and ultimately an improved energy efficiency to your home.

Typical values for double glass IGU
 IGU Thickness  IGU Configuration Number of Low-E coatings  Cavity Gas Centre Pane U-value to BS EN 673 g-value BS EN 410 Typical PVC-u Double Glazed Window
Whole window U-value Uw Window Energy Rating (WER)
 28mm  4-20-4  1  Air  1.5 0.7 1.6 -13 (C)
 28mm  4-20-4  1  Argon  1.2  0.71  1.3  +7 (A)
Typical values for tripleglass IGU
  IGU Thickness   IGU Configuration Number of Low-E coatings     Cavity Gas Centre Pane U-value to BS EN 673  g-value BS EN 410   PVC-u Window as above with Triple Glazed
 Whole window U-value Uw  Window Energy Rating (WER)
 28mm   4-8-4-8-4  1 Argon 1.3  0.63 1.4 -9 (B)
 28 mm  4-8-4-8-4   2  Argon  1.0  0.61  1.1  +2 (A)
 36 mm  4-12-4-12-4  1  Argon  1.1  0.64  1.3  -8 (B)
 36 mm  4-12-4-12-4   2  Argon  0.8  0.61  1.1 22 (A++)
40mm 4-14-4-14-4 1 Argon 1.0  0.64 1.1 +13 (A+)
40mm 4-14-4-14-4 2 Argon 0.7  0.61 1.0 +29 (A++)
44mm 4-16-4-16-4 1 Argon 0.9  0.64 1.1 +19 (A+)
44mm 4-16-4-16-4 2 Argon 0.6  0.61 0.9 +36 (A++)

 Please note many of our window and door units including UPVC, Aluminium, timber and composite will achieve higher overall U values than highlighted in the table above due to design of the frames.

Benefits to the homeowner

Correctly specified triple glazing will result in a overall lower U value for a window or door improving the comfort of the home and ultimately lowering heating bills. The addition of an extra pane of glass and lower U-value means tha the internal temperature of the glass pane will be closer to the room temperature due to the reduced heat loss through the glazing. This reduction in conduction and convection with the room reduces cold spots within the room and therefore the room is not only warmer but also more comfortable place to be.

Improved heat loss and comfort level will often lead to the home owner turning down the thermostat for the home heating system and therefore result in cheaper heating bills. Correctly specified triple glazing can results in a reduction in solar gain however the improved oveall U value and heat loss will more than compensate for this.

Acoustic Performance

When considering installing triple glazing in your home if improving sound reduction passing through your new windows is a consideration your must consider the thickness of the glass used to make your new IGU's. If all of the panes of glass in your new units are all the same thickness (ie 4mm) resonance occurs limiting the level of sound reduction. There are many different ways that you can improve the acoustic performance of your new IGU's, the simplest being to increase the thickness of one of the glass panels. Other options would include specialist laminated acoustic glass.