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What is daylighting and why is it important?

Effect of buildings on cognitive function and productivity

Daylighting is the relationship between architecture and how natural light is optimised in a space or place for greater health and wellbeing benefits.

By understanding how daylight flows into a specific space over the course of the day and at different times of the year, we can then influence how light is incorporated into the building design to benefit the end-user.

Effective use of daylight isn’t just about light however. The sun can be a source of heat within a building and having the sun shining through your window is also aesthetically pleasing creating a positive feeling of visual comfort for building users.

How daylighting design relates to the wider building performance Daylighting relates to the performance on two levels. The first is in terms of artificial lighting consumption.

A well-thought building will benefit from natural light for longer during the day. A great example of this in action is the Velux Maison air et lumière houses project where homeowners found they turned their artificial light on one hour later than everyone in their neighbourhood.

Secondly, daylighting also has an impact on energy performance as, essentially, light is radiation. This means it can contribute to thermal comfort in winter and in turn, reduce a building’s heating needs. By the same token however, too much light during the summer means a space may require extra cooling. A good daylighting strategy should consider how a building varies during the seasons to prevent it being too cold or overheating, but also how the flow of light works alongside windows and rooflights, as well as dynamic shading protection. [Read more about insulation and ventilation

Daylighting considerations for building designs
Currently, daylight is used by architects and designers as a tool to create very complex and impressive buildings – The Koch Center for Science, Math and Technology in Massachusetts, USA, is an example where designers have constructed the building with an all-day light effect.

However, more broadly, understanding of the natural course of the sun and its effects depending on the orientation of the building and its location could be better understood by the design community.

As we’ve seen with projects like 20 Fenchurch Street in London (nicknamed the Walkie Talkie) where the building’s design created glare and reflected light onto streets below, mistakes still happen, and if architects don’t master the tools available and/or don’t have the physical or technical knowledge to interpret and implement results correctly, things can go wrong. Buildings standards like LEED or BREEAM are forcing architects to consider daylighting but without a genuine understanding, many are just ticking boxes.

Harnessing the benefits of natural light
Used effectively, daylighting techniques can have a positive effect on building design in terms of its performance and comfort.

Fortunately, there are several emerging technologies and products that are helping designers to harness the power and benefits of natural light. Products that redirect or diffuse light such as complex fenestration systems are one such example. These systems have sophisticated louvers and mirrors that can change depending on the season.

Redirecting products such as these, as well as other systems like microshades, help with glare problems while also maximising available light. These systems are particularly useful in very sunny environments as they protect building users while still allowing light to diffuse into the room.

Another emerging trend is circadian lighting and understanding the non-visual effects of light. As daylight can affect aspects such as our metabolism for example, understanding its effects helps designers create ‘living’ spaces that are more responsive to users’ needs and not fixed in their design.

To find out more about the light and circadian rhythms, read Jayne Cox’s post on ways design can improve your sleep.

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Disclaimer: The sole responsibility for any views expressed lies with the author(s). Any opinions shared do not necessarily represent the views of Saint-Gobain.

Laura Thuillier
Laura Thuillier Development Engineer
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