Daylighting Performance in Residential Buildings

The amount of daylight entering a building and its distribution depend an both interior and exterior factors. In Hong Kong, most buildings are built close to each other and hence the external environment plays a significant role in the daylighting designs. A study of the local and overseas Building Regulations indicates that the existing statutory documents in Hong Kong and Britain may not be conductive to effective daylighting. Key building parameters affecting daylighting performance in Hong Kong are presented. The quality and quantity of daylight for typical interior rooms have been assessed in terms of room depth, no-sky line and average daylight factor. It has been found that the daylight level of residential flats can be severely reduced due to neighbouring buildings. Without any sky obstruction, the average daylight factor ranges from 0.5% for kitchen to 3–5% for bedroom. Sky blockage would be critical for obstruction angles greater than 60°. These imply that many residential flats in Hong Kong would have to rely on supplementary electric lighting.