Glass sealed units and how they work


The right type of glazing really matters. Key factors here are the glass types used, the spacer bars and the gas filling between the sheets of glass and number of sheets.


Our double, triple and even Quad units are produced with one or two, even 3 panes of low-emissivity (low-E) glass respectively(Thermafloat) This heat reflective glass reduces heat loss from the building. It allows the warming infra-red rays into your home but reflects into the room heat that would otherwise be lost to outside. In some cases, we can include a solar reflective outer sheet to keep the building cooler in warmer months and low Ion for North facing structures that allows more light energy in. Thermafloat is also suitable for external panes for  enhanced solar control.


Most of our units are Argon filled in some extreme cases we can fill with Krypton. These are inert, non-toxic, clear, odour-less gasses used in between each glass layer to minimise heat transfer between the interior and exterior of the window. Argon is 60% better as an insulator than air. Krypton is more efficient again with when utilized with thicker glazing systems.


The spacer bars (the structural edges between the panes of glass in a sealed unit) are a potential heat loss area if still using aluminium. Our warm edge non-metallic spacer bars are made from a low conductivity plastic and have superior insulation properties. They also keep the glass at the optimum distance apart, accommodate thermal expansion, and prevent moisture and gas leaks.


Both our Tilt and Turn inward, and casement outward opening units have excellent seals and gaskets, giving low air leakage rates.

These five factors – frame material, glass type, sealed unit type double triple or quad-gas filling, warm edge spacer bars and the seal used all add up to provide high-performance, thermally-efficient windows and doors and glass roof systems.

Should I go for triple or Quad glazing rather than double glazing?

In our view, generally, yes to Triple possible Quad in extreme conditions.

When using our windows doors and glass roof systems the thermal performance of a triple and quad glazed window is usually 41-62% more energy efficient than a double-glazed version but typically between 10-18% more costly. Noise reduction can also be enhanced depending on the glass package installed. We can include acoustic laminate 8,5- 10,8 to 14.4mm options for enhance DB reduction.

This improved thermal performance is delivered as a result of the extra insulation provided by the third pane of glass and the additional layer of argon gas. Couple this with a thermally efficient frame and you have a truly high-performance window.

A number our triple glazed windows are suitable for passive house development as standard. You can see from the illustrations below, just how double and triple glazed options work,and differ you can see  the temperature differences between the two areas ie outside to inside and compared to each system.

Thermal performance

Using our high-performance energy efficient windows and doors as part of your new build or refurbishment project can significantly improve the energy efficiency of your home. For heaty loss and solar gain, when selecting new windows, you should consider the durability and performance of the whole unit.  Frame materials, glazing features, gas fills and spacer bars all affect the performance of windows and doors, its not just about winter months with heat loss but the warmer summer months too, windows must help in keeping a building cooler with the glass application.

Improving the thermal resistance of a window door or roof frame will contribute considerably to the window’s overall energy efficiency (its U-value). The U value is the rate at which a window or door conducts non-solar heat flow, the lower the value the more energy efficient the unit is.


 Outside .                                         Inside.