The water bags are 2400 mm wide by 11.6 m long with a depth of 250 mm. The water in the closed bags provides thermal storage for warmth in winter and coolness in summer. Insulation covering the water bags acts as a movable thermal valve. The Skytherm House maintains comfortable interior temperatures by juxtaposing insulation and mass to minimize interior temperature swings. In summer , movable insulation covers the water bags during the day to prevent heat gain from solar radiation.
Heat flows from the occupants to the cool ceiling and into the water bags, where it is stored.
At night the insulation is rolled away from the water bags and the stored heat is radiated from the water bags to the cool night sky. The next morning, the insulation is rolled over the water bags to prevent heat gain from the sun and the cycle is repeated. In winter , insulation covers the water bags during the night to prevent heat loss to the cold night air. During the day, the insulation is rolled back to expose the water bags to the radiant heat of the sun. The stored heat in the water bags radiates to the interior to warm the occupants.