Insights

Ruth Kelly Waskett on the power of daylighting.

Read part 1 here.

The ecological impact

But while LED systems are revolutionary, Ruth says they are no magic bullet. She explains, “there is an energy impact to artificial lighting – in order to deliver the blue parts of the spectrum, you need to put more watts in. It literally costs energy and money to make it circadian-effective.

In contrast, natural light has huge potential for energy savings. And the answer, Ruth believes, is to have daylight at the top of the agenda when designing new buildings.

If done right, daylighting holds the key to solving the people/planet conundrum, with natural light, people get exactly what they need, when they need it, and artificial lighting energy can be minimised. It’s a win-win, but it requires a re-think in the way we plan our cities. Buildings are too often designed to fill large square plots. If buildings were shallower, we will have less density and better daylight ingress. But the viability of many developments depends on the building footprint being maximised in the plot.

Retrofit limitations

Of course, improving the natural light in existing workplaces is more complex. We can improve daylighting by using lighter coloured finishes on major surfaces, such as walls, floors and ceilings and we can design the interior layout to ensure people spend most of their time it the best daylit areas. But we are often very constrained by existing openings in the façade, and swapping the core of the building for an atrium is a drastic approach – even atriums have their limitations.

And when it comes to new projects, there is a delicate balancing act between light and thermal comfort. Swathes of glass may seem the obvious solution, but these can have heat and health implications.

So, heat is much more heavily controlled by building regulations, which is only right. When we work with architects to improve daylighting, we always have to be mindful of not creating an overheating issue.

That said, certification standards like BREEAM and WELL have helped us enormously, because they give an external driver. If a building is aiming for BREEAM ‘excellent’ for example, one of the targets is around daylighting. We can then work together with the client to address any lighting deficiencies and improve the building, which is so rewarding for everyone involved. It’s always a joy to work with a client that clearly prioritises employee wellbeing.

A pioneering project

One such project is Timber Square, a vast Landsec development in Southwark. Currently under construction, it aims to be the largest commercial development in the UK to use cross-laminated timber. Not only is it targeting net zero in construction and operation, but the two office buildings will meticulously balance daylight and thermal performance.

It’s a remarkable project. We’ve done extensive daylight analysis, and worked with the architect – Bennetts Associates – to develop the façade design around daylight and overheating. Each façade has a different orientation, so the light profiles vary, as does the potential for overheating. A lot of buildings are designed in a very homogenous way, but we’ve ended up with a façade that has different degrees of openness as you go up and around. It’s an exciting design that actually responds to the environmental conditions and urban landscape. It’s been such a pleasure to work on – being able to shape a building to maximise daylight is incredibly satisfying.