PASSIVE SOLAR LIGHTING

Earth sheltered homes can't have windows in their sheltered walls, so you need some way to bring in additional light. You could always use electric lights, but there's plenty of free light available if you provide a way for it to enter. There's nothing really new about using skylights, but the way we installed them improves on the standard.

We removed the translucent ceiling panel below one skylight to show you the interior details. Since the skylights are already located to put light where it's needed most, we included recessed electric lights for evening illumination. Because of the gloss white interior, when you turn them on the whole ceiling panel glows pretty much just like in the daytime. Further, we added two sets of screened vent holes at the bottom and top of opposite sides in the light well. Natural convection moves air from the attic through these light wells, preventing heat buildup in what is essentially a solar collector. Lacking that ventilation, the temperature in the lightwell would build up and radiate heat into the house.

In the large (3 ft x 6 ft) skylight above the kitchen island we used four fluorescent tubes for illumination. That's plenty of light for cooking. The larger volume of this lightwell made convective cooling impractical, so we installed a solar powered electric vent fan inside. It circulates attic air through the light well as long as the Sun is shining.