April 25, 2023

The sustainability of glass

Written by Michelle Martin

Glass sustainability

When it comes to architects' specification, sustainability and performance of architectural glazing is one of the most important aspects to consider. This is because of the adoption of a stringent set of measurable factors that glazing solutions are judged by, not just its U value. These determinants focus on the materials used for the construction and assess the recyclability as well as carbon required for manufacturing. In addition to this, it also evaluates the impact that the glazing would have on the wider energy use of the building, with factors such as solar control, ventilation and thermal insulation playing a significant role in the overall sustainability of an architectural glazing installation as a result of it mitigating the amount of energy expenditure required to regulate temperature as a result of high performing glazing solutions.

Coinciding with these components to ensure high levels of sustainability is a set of frameworks of which architects must adhere to ensure quality glazing performance, the 3 most applicable documents are as follows.

Approved Document L - covers the conservation of fuel and power and denotes how much energy a building uses and the insulation. It denotes the building regulations required for thermal performance of a glazing on a project.

Approved Document O – provides guidelines for preventing overheating in house design. This is one of the newest areas of regulations and was brought into fruition back in 2022.

Approved Document F - Outlines the requirements for ventilation for buildings.

Different Glass types and suppliers-

Heated glass and Finnglass-

At IQ glass we partner with several different suppliers to provide a variety of different glazing solutions with different specifications to best suit the needs of the project.

An example of one of these types of glazing is heated glass. Which is an electric glazing solution that involves applying a conductive coating to the internal face of a glass unit. When you pass electricity through that coating it provides a radiant heat. This type of glazing has numerous applications from condensation relief to providing a sole heat source for a space, making it the ideal solution to adopt for indoor swimming pools.

The largest supplier of heated glass in Europe Finnglass has conducted a large research study into the carbon foot print of heated glass. The factory where this electrical glass is made is powered by 100% green electricity created from renewable energy sources, and the waste heat from the process is then used to heat the offices and plant, heated glass firmly establishes itself as a great advancement for sustainable building practises whereby the combination of heated windows and a geothermal heat system, they achieve a smaller carbon footprint than district heating alone.

Guardian and solar control glass-

Another type of glass that champions sustainability is solar control glass, which is described as a whole family of glasses that include a specifically designed coating to reduce solar radiation passing through glazing. To achieve this a thin metal oxide coating is applied to the inside of the external glass pane that reflects the short-wave radiation rays from the sun away from the internal space preventing them from becoming trapped inside and increasing the interior temperature.

Most modern solar control coatings are designed to maximise natural light whilst controlling solar energy, and much like heated glass aid sustainability due to it reducing the amount of external energy expended on altering temperatures in a space thanks to the high performance in controlling solar energy.

Saint Gobain- low e glass ORAÉ®

Another glass type that can be adopted to positively contribute to sustainability is Low E glass. Low E glass is the basic level of insulation applied to all IGU’S. Low E stands for low emissivity which refers to the resulting effect it has on a glass unit, creating a surface that emits low levels of radiant thermal heat energy. Low E coatings are typically applied to the interior surface of the internal pane of glass. To provide the optimum improvement of thermal insulation within the glass, to reflect radiant energy back into the building in turn improving insulation as well as reducing the UV light through a glass unit.

ORAÉ® glass  by Saint Gobain was announced in July 2023 as the world's first lowest carbon footprint glass substrate. 

Whilst the vast majority (at present) can ill afford ORAÉ® glass with a minimum order requirement of 400m square, the implementation of specific glazing solutions can still contribute a large amount to sustainability, through improving the thermal performance allowing for the mitigation of external energy expenditure, or through the adoption of more sustainable building materials requiring less carbon for manufacturing and installation.


If your project would benefit from the adoption of sustainable glass solutions, contact the team at IQ Glass on 01494 722 880