Using solar shading to keep a building cool in a heatwave

With the UK set for a spell of hot weather in the next fortnight, typically as the schools return from summer holidays, many will be looking for ways to keep cool without relying on energy-sapping air conditioning units or fans.

And with heatwaves likely to become more frequent in the future, it’s crucial we all adopt methods of keeping cool that will not have a negative impact on the environment and our energy bills.

Therefore, we’ve put this blog together to highlight four ways in which solar shading can be used to keep a building cool in a heatwave, identifying some of the more practical and permanent solutions.

External blinds

Solar gain is the main reason for uncomfortable internal environments during a heatwave.

The best way to eliminate this is to use an external blind, which prevents much of the heat getting through to the glass, let alone into the room.

Indeed, the Part O Building Regulations introduced in 2022 stipulate external blinds should be used to reduce solar gain on all new-build residential projects. We discuss this in greater detail here.

Warema’s external roller shutters are an excellent example of how these systems can be used to keep occupants cool in the warmest of conditions. Suitable for both new build and retrofit projects, they can be installed without damaging existing structures.

Other well-placed external structures will also shade the building, reducing the inside temperature. For more information on external blinds, contact us and our expert Specification Team will happily assist.

Internal metallised blinds

Internal blind performance can be vastly improved by using a metallised fabric, created by coating the blind with a thin layer of aluminium. The metallised surface is installed facing the glazing and can reflect up to 82% of the solar energy entering the building through the glass.

Metallised fabrics work to their maximum potential when paired with a fully automated systems, as the blinds can be programmed to change in height throughout the day to optimise the energy efficiency of a building. Relying on human operation can limit the performance of these fabrics.

We discuss metallised blind fabrics in greater depth in our RIBA-accredited CPD, ‘Improving Sustainability through Performance Solar Shading.’ You can book on to our next webinar, or contact us if you’d like our team to deliver a lunch and learn presentation at your practice.

High performance curtain fabrics

If curtains have been specified rather than blinds at the window, what are the best curtain fabrics to protect against heatwaves?

Layered, multiple-weave fabrics with blackout properties offer the best thermal reduction (as well as keeping more light out than most). Creation Baumann, one of our curtain fabric suppliers, offers a range of 140 ‘Glare&Heat’ protection fabrics, perfect for controlling the internal temperature of your building.

Bustle delve into the topic further by identifying the best three thermal curtains here.

Optimum usage of blinds / curtains

In general, when the temperature is hotter outside than it is inside, it’s essential to keep the blinds down or curtains closed, and the window closed too. Opening the window in an attempt to cool your building during a heatwave will only increase the internal temperature.

Once the external temperature is reduced, usually later in the day, the window can be opened but the blinds and curtains should remain closed to prevent heat gain.

Get in touch with us if you’d like any further information about using solar shading to keep cool in a heatwave. Alternatively, if energy efficiency is at the heart of your projects, we’d be delighted to assist.