Light pipes (such as tubular lighting) are simple structures that allow the transmission of daylight from outside to inside a room. They are an increasingly popular product, with CIBSE Building Journal (September 2003) stating that there are now an estimated three million pipes installed...

A method is proposed for estimating the electricity consumption (and associated carbon emissions) of a defined electrical-lighting configuration in an office building, accounting for the daylight contribution from windows and rooflights. Heat gains due to lighting for an average day in each...