In its simplest form the brise soleil is little more than a textured wall, and yet in some of its better-known incarnations this architectural device is stunning and complex. The Milwaukee Art Museum is world-famous for its folding, automatic wing-style brise soleil. However, in other cases they just take the form of a concrete surface – horizontal or vertical – with holes in. The idea is that these will let through some but not all of the sunlight that hits them. The exact amount will rest on a number of factors, including the climate, latitude, direction the building is facing and the time of day and year. Variations on this theme include glass louvres and other forms of external louvres. Although they may appear very different, the same principles are employed, and for the same ends.

In general, the purpose of all these devices is to limit the amount of sunlight coming through them at various points, whilst still making the most of it at other times. Take a large, modern office building, for example, which may have a large south-facing window. In the winter this will be a asset to the building (so long as it is properly insulated) since it will let in large amounts of sunlight – thereby cutting down on artificial lighting and heating and their associated costs. Passive, natural heat and light are typically more comfortable than central heating and electric lights. However, in the summer such a large window would present a major problem. Without adequate shading, the amount of heat and light it lets in would make the office space hotter than was comfortable (or, in some jurisdictions, legal). The purpose of the brise soleil and external louvres are to adjust the incoming sunlight at different times of the day and year. Low-angle morning/evening and winter light is encouraged; hotter, high-angle midday and summer sun is blocked.

Some glass louvres are built with photovoltaic systems to generate power as well as limit unwanted light and heat. In other cases, external louvres are automated so that their angle can be customised for the exact circumstances and weather conditions; the one-size-fits-all approach is useful up to a point, but can often be improved. But even a basic brise soleil can make a huge difference, lowering the need for heating and air conditioning, and therefore improving energy bills in the process.

Please visit http://www.maplesunscreening.co.uk/ for further information.