What Role do Windows Play in Sustainable Housing?


Concern about global carbon emissions has never been higher. The Paris Agreement commits the signatories to reducing global average temperature to below two degrees above pre-industrial levels. This is critical to combatting climate change, but it’ll only happen if practices change. And among the most important contributors to the effort will be those whose job it is to design and build houses. The British government continues to implement ‘green schemes’ to help achieve its goal of net-zero carbon emissions by 2050.

The house of the future is one that can be built and maintained in a sustainable way. In an ideal world, they’d be perfectly self-sufficient when it comes to their energy needs. The construction industry is pushing itself toward that goal through a series of incremental improvements in efficiency. These are coming as a result of new technologies, architectural methods, and increasingly stringent building regulations.

The Importance of Windows

Among the more notorious points of weakness in any building, when it comes to heat retention, are the windows.

Energy Efficiency

Windows have a big say in whether a given space is energy-efficient. A single pane of glass will transmit heat quickly from one side to the other. Two panes of glass, with a layer of vacuum or inert gas in between, will transmit heat that much more slowly. It’s this principle that makes double-glazing the standard choice. Efficiency is rated using a lettered system, which provides the scale for the development of energy efficient and sustainable housing.

Natural Light

Among the most important functions of a window is to increase the amount of natural light in a property and to reduce reliance on artificial light sources – and windows can serve this function in a number of ways. VELUX windows, skylights and sun tunnels provide a source of natural light, even in the more secluded parts of the house, where exterior windows are not practical. Natural light confers a number of health benefits, which means that homes which score well here are likely to be desirable, even if we discount the environmental upsides.

Solar Gain

But windows can also be a point where energy is gained. If windows are positioned in such a way as to benefit from the incoming sunlight, then they’ll draw in as much energy as they lose, even during winter. In the northern hemisphere, a south-facing window will benefit more from heat gain than a north-facing one.

Blinds and Curtains

The effectiveness of a window when it comes to thermal performance will depend on the quality of curtains and blinds installed. Heavy curtains will form a barrier, preventing warm air in the room from mixing with the cold air by the window. This only applies if the curtains have been drawn, however – which is why automatically-drawn curtains and blinds might be a boon, particularly in larger spaces and office buildings.


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BDC 318 : Jul 2024