The Sustainable Future of Fenestrations
The building envelope and the choice of fenestration systems impact the energy use of a building through thermal heat transfer, solar heat gain, visible transmittance and air leakage. Improvements to fenestration systems such as thermally broken frames, insulating glass units, triple-pane glass, electrochromic and thermochromic glass, and double-glazed wall systems, contribute greatly to the energy efficiency of the facade.
Insulating Glass Units:
Technological advancements have made it feasible to manipulate the proportion of transmittance, reflectance, and absorption of heat. The use of low-e coatings, thin films, and triple-pane glass help reduce the amount of solar radiation transmitted inside the room. This significantly lowers the load on mechanical forms of cooling.
Climate Specific Fenestrations:
For an efficient and sustainable façade, it is advisable to adopt a climate-specific design strategy. In cold climates, one must opt for products with a low U-factor to keep heat loss to a minimum. Fenestrations with high SHGCs (Solar Heat Gain Coefficient) help utilize the solar heat. In warm climates, products with low SHGCs offer a great potential for reducing solar ingress. Windows with low-e coatings and spectrally selective coatings, are effective at lowering heat gain and can reduce energy consumption of the building.
Aluminium Doors and Windows:
The use of aluminium systems allows for large glass spans and bigger IGUs. The strength-to-weight ratio of aluminium handles the weight of the IGUs with ease. Aluminium frames reduce conductive heat loss and improve the thermal performance of the building. Furthermore, aluminium can be recycled indefinitely without any loss of its inherent strength and quality characteristics. Over 60% of aluminium production from the bauxite ore uses hydro-electric power with zero carbon dioxide emissions. When aluminium is recycled, there is a reduction in excess of 80% of the energy consumption required for the original production from the ore, making it a truly sustainable material.
Today, fenestrations are continuously being developed into the ‘fenestrations of tomorrow’ and are fast becoming a necessary ‘climate screen’ for conserving the energy of a building.
