Solar Power

Ennis Pyramid House Takes Advantage
of Active and Passive Solar, Plus Wind

Whitney Lake’s Pyramid House near Ennis incorporates active and passive solar features, along with a small wind-energy system. The distinctive off-the-grid structure was built and furnished with an eye to energy efficiency and conservation. Three first floor walls and all four faces of the pyramid are made of R-Control Panels manufactured by Big Sky Insulation of Belgrade, Montana. The panels are constructed of 10.5-inch and 12.5-inch expanded polystyrene sandwiched between two sheets of osb (oriented strand board). "They have excellent insulation qualities, boasting an R-value of between 39.88 49 at 40 degrees," says Lake.

A trombe wall on the south works by thermo-circulation. Lake explains how it works: "Cold air falls through vents in the floor; the south-facing concrete (painted a dark color) is heated by the sun; the warmed air rises and is vented to the living space. Cooled air falls and begins the cycle again." The glass front was installed by Valley Glass of Bozeman, Montana.

A Helio-Pak 16, made by Heliodyne, Inc., is another passive solar feature. It uses a glycol-distilled water solution that circulates via a photovoltaic controlled pump. 

"The warmth of the radiating sun does the work," says Lake. "The heat is transferred in a loop to bring well-temperature water up to 80-120 degrees."

He generates electricity using the sun and the wind. His solar array includes Siemens and Kyocera photovoltaic panels that produce 1180 watts/hr during peak insolation hours. 

A Bergey Wind Turbine, designed to withstand winds up to 120 mph, produces 1750 watts/hr in 35 mph winds. "The three blades are extra stiff for severe weather resistance," says Lake.

Take an online tour of the house. 

Photos courtesy of Whitney Lake.