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Understanding the Thermal Qualities of Structural Glass Roofs

Understanding the Thermal Qualities of Structural Glass Roofs

Having a structural glass roof installed on your property from Natralight will help to increase the building's thermal efficiency.

If you have your glass roof installed on an angle, this will affect the overall thermal performance, which is due to the convection currents that occur inside all double or triple glazed units.

When a glass unit is vertical the gas filling between the glass panels heats from the building's internal temperature, with this gas filling then rising and the heat escaping to the external of the glass panel. This causes the gas to cool again and sink. This gas movement also causes a current in the gas filling and benefits heat loss to the external of the glass panel.

Improved Insulation

When a glass unit is titled the same thing happens but the vortices occur more frequently all across the glass unit as the convection currents will only travel vertically. This means that you get more convection currents which help with heat loss to the external glass panel and reduce the thermal performance of the glazing.

For example, if the thermal performance of a double glazed unit in a vertical position was 1.2 W/m2K when its tilted on its side, the thermal performance reduces quite dramatically to 1.7-1.8 W/m2K. 

In order to achieve thermal performance (uG value) lower than 1.4-1.5W/m2K, Natralight would recommend specifying triple glazing for any structural glass roof or rooflight installation.

Specifying Triple Glazing for Rooflights

A standard triple glazed unit achieves an Ug value of 1.2W/m2K when installed at a horizontal angle, to be used as a glass roof or structural roof light.

Thermal performance can be further improved by introducing a solar control coating to triple glazed structural glass unit, reducing the Ug value to 0.8 W/m2K.

Natralight will still be able to achieve far below the requisite Uw value of 1.5 W/m2K for all roofing elements, dependant on the fixings and finishes of particular projects.

Want to Know More? Contact Us Now

If you are considering a structural glass roof for your property, please get in touch with Natralight today.