The effect of glazing upon energy consumption within buildings

Figure 1 shows how EAV, the average daylight illuminance m a room, varies with sky illuminance. The required light level is given by the ~.?~Y8 Y j.i6r~s q.i ~ Vii~3:ii~..~i..~4s~ ~ ~^~ and it can be seen from Figure that this level of is more than provided for whenever the sky illuminance exceeds the value of Eskys’ Below this level of sky illuminance the electric lighting must be switched on and this fact can be used to calculate-7L, the energy consumed by the electric lighting: