Do's and Don'ts of Lighting in Building Design

Natural light can make a huge difference to any room or building. Countless studies have shown that the natural light within a building can affect people’s health, and as we live in a society when most people spend 90% of their time indoors, natural lighting in building designs is becoming more important than ever. If you get the lighting wrong within a building, it can be left feeling dark and dreary with unhappy and uncomfortable occupants.

The importance of using natural daylight in building designs is not only down to the health and psychological benefits of the occupants but also the ecological issues of the modern world because it means less energy consumption in the form of artificial lighting. In typical buildings, lighting accounts for 25-40% of energy consumption, so by allowing in more natural light and controlling lighting and heating, financial savings could be considerable.

When designing with natural light, it’s always crucial to have the needs and well-being of the occupants in mind due to the huge physiological, psychological and physical efforts of daylight. For example, natural light can help hospital patients to recover and school pupils to perform better academically.

Here are some of the do’s and don’ts to consider for each element of designing with daylight:


It’s true that a building with a large number of windows will allow maximum amounts of daylight to flood in. However, if those windows do not have the correct glazing to meet the needs of the building’s occupants, it can create glare, areas that are too bright or an unpleasant environment for the occupants. If there’s too much glare in a certain area, occupants will usually decide to draw the blinds or curtains and turn the lights on which completely defeats the purpose of your design!

Choosing the correct type of glazing and shading is critical to designing with daylight. Glazing can help to reduce glare and prevent solar heat gain whilst still allowing natural light to pass through, keeping occupants cool in the summer and warm in the winter.

At Xtralite, we supply a range of glazing materials and advice to help you specify the correct glazing for every project.


In smaller buildings or for the upper storeys, skylights can provide some of the best natural light spread across a larger area. You must carefully consider the skylight you install. It must be fit for the purpose and provide the building with the right amounts of sunlight without overheating or losing too much heat in the winter. Just as selecting the wrong type of glazing will defeat the purpose of your natural lighting strategy, so will a poorly selected skylight.

Skylights provide three times more light than the same area as a window and can also provide a more even distribution of light, particularly in larger buildings.

Heat Loss or Gain

In many buildings, the amount of light entering the building should be controlled by your designs to prevent overheating and protect the comfort of the occupants inside. Tinted materials and the correct type of glazing can prevent these problems and ensure that the building receives the correct amount of lighting without becoming too warm.

The correctly selected glazing system should let in more light and less heat than a typical window, allowing for daylighting without impacting the building cooling load in the summer.


Although this is more applicable to new building designs, it can still be considered when installing skylights or rooflights and their positioning. If a building is in direct sunlight all day, the type of glazing will need to be considered to prevent overheating and too much glare throughout the whole day. Can you construct the skylight so that it maximises the natural light but will help to prevent glare and overheating?

Shading should also be considered in the positioning of glazing. South facing windows can be shaded to keep intense summer sunlight out but allow winter sun to warm the building.

Designing with daylight involves carefully balancing heat gain and loss, glare controls and variation in the availability of daylight. Successful designs will consider shading to reduce glare and excess heat in the workplace.