A Procedure for Calculating the Potential Savings in Lighting Energy from the Use of Skylights

A step-by-step procedure is presented for determining the lighting energy trade-offs between artificial lighting and skylighting based on the ability of each to provide average horizontal footcandles on a work plane.

This paper explains a procedure for calculating the lighting energy that can potentially be saved by turning off some or all of the artificial lighting in a room that has skylights. It is not a procedure for designing a skylighting installation, although it contains many of the elements of skylighting design. It is not a procedure for determining the total energy balance within a space, although it could be extended to do so by including heating and air conditioning considerations and the thermal losses of skylights. Rather it is a procedure for determining the lighting energy trade-offs between artificial lighting and skylighting based on the ability of each to provide average horizontal footcandles on a work plane.