3.2 The Sizing Of Skylights
It is important to properly size skylights. A skylight too small restricts the amount of savings to be obtained by being able to turn off the electric lighting. A skylight too large will result in excess solar gain in summer and heat loss in winter and create comfort problems and offset savings from daylighting.
Proper skylight design must account for parameters involving:
Heating & cooling
Fortunately, the Heschong Mahone Group from Sacramento, CA has developed a free tool (SkyCalc®) for optimizing the Skylight-to-Floor Ratio, i.e. what percentage of the floor area should be represented with skylight area.