1

The daylight factor (Df)

In architecture the daylight factor is the ratio of the light level inside a building to the light level outside the building at the same time of the day under overcast skies. The higher the Df, the more natural light is illuminating the room. The general rule of thumb for effective daylighting in a room is to make sure that the amount of glazing installed equals 10-20% of the floor area. Windows installed at height provide the opportunity for better light distribution

2

Window orientation

Allow daylight into a building from every direction, especially through windows installed at height. Ideally choose windows with a slim frame profile and high glass-to-frame ratio. The shape, size and position of every window within a façade will have a significant impact on the distribution of daylight across every room. Avoid placing transoms or glazing bars within the field of view

Existing features such as neighbouring buildings, hills and trees can affect the amount of daylight that penetrates a window. To maximise the energy performance of the windows it is therefore essential to take existing shading into consideration at the early design stage.

3

Sun screening

Low-energy buildings need to maximise their use of free solar heat. However, if not controlled effectively, passive solar gain can result in the overheating of spaces within the building. It is therefore essential to control the amount of solar gain entering a building during the summer months by adding sun screens to the windows. There are many options available on the market, including internal, external and automatic screens, but whatever your choice, we suggest using flexible solutions that don’t affect the view.

4

Daylight and seasonal changes

Daylight is a challenging element to work with as it changes - both during the day and across seasons. When talking about daylight, a distinction must also to be made between the diffuse light experienced on a gray day, and direct sunlight, characterized by a warm light with shadows and greater contrast. Buildings must be designed to take both scenarios into consideration ensuring a sufficient flow of daylight in the winter without having to struggle with overheating in the summer months.

5

The power of light and shadows

The purpose of architectural lighting is to enhance the overall spatial experience. Both light and shadows are necessary to establish the limits of a space , and when used effectively they can also create a comfortable environment in which to work or live.  The use of too much colour or pattern into the internal spaces can detract from the architectural shapes and obscure the details, while the contrast between the light and dark creates depth. In this context, daylight can then be seen as part of an aesthetic whole, as it interacts with the surrounding colours and surfaces adding drama and energy, or creating texture and mood.

VELFAC 200

Unique construction designed to let more light in

VELFAC 200 is a beloved design classic in both the UK and the international market.

The unique 54mm “floating frame” deliver excellent performance and maximises the amount of daylight entering the building thereby reducing the need for artificial light and heating.

"We wanted to make sure the building could stay comfortable without the need for mechanical cooling, even through the hottest summer. ‘This meant the placement of smaller windows on south facing facades, to manage solar gain, and the specification of multiple opening units across the building, including high level teleflex-operated lights."

- Corrie Rounding, Architect, Innes Associates