Green Energy Expert Mike Menkes Part One

What’s the difference between a solar tubular skylight, a traditional skylight, and a solar window? While the three terms are often used interchangeably, they each have different meanings. To help straighten out the confusion, CalFinder Solar recently interviewed Mike Menkes of GreenEnergyFlorida.org and PowerBillDiet.com. Mike works toward reducing energy consumption and carbon footprint for commercial and residential applications.

Mike explains that differences between the three consist of several factors, including composition, placement, and purpose. All three barriers, however, come with the benefits of aesthetics, increased production, and reduced stress levels that come with the presence of natural light.

To separate the three, Menkes provided us with the following information on solar tubular skylights, traditional skylights, and solar windows.

Tubular skylights are constructed with a dome [1], an optical plastic polycarbonate or acrylic composition set in a metal flashing [2], a reflective metal tube [3], and a diffuser located on the interior ceiling [4]. Given this configuration, sunlight bounces through the tube and spreads throughout the entire interior of the room.

Traditional skylights can generate unwanted heat. Tubular skylights, on the other hand, prevent heat from pushing down into the room. At the same time, unglazed skylights enable rising warm air to cool in the winter, but tubular skylights provide a protective barrier between the cold air outdoors and the warm air within.

In configuration, skylights are simply windows located on the roof, allowing light into the room. They can consist of flat glass or a domed variety. For proper energy efficiency, the skylights can be double or triple glazed.

Skylights help decrease overall energy costs by increasing the level of natural light within the home. At the same time, skylights can make a room feel larger and more picturesque. Like conventional windows, some skylights can open to provide ventilation.

Solar windows are not placed on the ceiling but along the wall. They refer to glass that is installed specifically on the south side of a building for the purpose of generating solar gain. Sunlight that enters through solar windows heats the air, floors, walls, ceilings, and even furniture.

South-facing solar windows should be highly transparent, thus having a high Solar Heat Gain Coefficient (SHGC), while windows facing east and west should have a low SHGC to help block unwanted sunlight during summer months.