It is clear that there is an opportunity for architects and specifiers to make much better use of daylight in buildings throughout the design process. Indeed daylight should play as central a role in the design as technical installations. However, all too often it is overlooked, as Paul Hicks, sustainability and design manager at VELUX, explains
Daylight has been used for centuries as the primary source of interior lighting and has been an implicit part of architecture for as long as buildings have existed. The first architectural guidelines were developed over 2,000 years ago and even then they acknowledged the importance of daylight in design, providing guidance on how to measure the amount of light coming into a room.
However many of us still aren’t making full use of daylight benefits in building design. The provision of daylight in buildings must be considered at every stage of the design and construction process. The focus on light in architecture is ever prevalent, and the right balance between light and dark is key.
Currently, the Code for Sustainable Homes require that in new build houses, kitchens should have a minimum daylight factor of 2 per cent, while living areas and home offices should have a minimum daylight factor of 1.5 per cent. However, research over time has shown that a 4 per cent daylight factor is perceived as being a daylit room.
The current British recommendation for window glazing is 20 per cent of the total floor area. Despite there being no concrete regulations for any building, 20 per cent is suggested with good reason.
If a building is designed with window glazing that is less than 20 per cent of this floor area, then the home or business owner will inevitably experience poor levels of daylight, resulting in increased use of electric lighting, which in turn will have a considerable impact on energy bills. It is therefore important when looking at the structure of a building that it has as much access to natural daylight as possible. It is important to consider how and where daylight enters, not only the amount of windows but the placement and orientation of them.
An easy, accessible solution for this is roof windows. By the very nature of the product, roof windows can let in up to twice as much light than a conventional vertical window because the glazing is pointing directly at the light source. Roof windows are also a successful way of supplying more daylight in the heart of the home, thereby illuminating areas of space that might otherwise be quite dark.
Roof windows offer consumers a contemporary design look. With a combination of lots of daylight, fresh air and a clear view, roof windows can create the perfect environment.
However, the effectiveness of roof windows shouldn’t have an impact on the amount of glazing incorporated into a design. It may be tempting to only allow a 10 per cent glazing to floor area ratio because of this effectiveness, instead of using the building regulation guide of 20 per cent, but why overlook the opportunity? With more roof windows you can improve and enhance the internal space and maximise daylight in the design. This gives you and your client the option to create a more desirable, energy efficient home.
The height from the floor and the length of the roof window should also be taken into account in order to maximise light levels in the room. When planning for this, you must afford allowances for how the window will be operated, how much of the outside should be in view (ground, trees, sky etc.) and take into account the pitch of the roof. The lower the pitch, the longer the roof window should be to maximise the view out.
Taking this element of design into consideration enables you to plan the space so that it will gain access to natural lighting, which in turn decreases energy costs over a long period of time. Access to natural lighting can be achieved easily by including the installation of roof window space.
Creating a better living environment depends heavily on daylight. It transforms a space and if planned in the right way, can help create a positive, healthy living and working environment. It is key to consider daylight and the placement of windows proactively at the beginning of the design process, rather than reactively.