Bungalows with solar space heating. The south face of the structure incorporates a brick inner wall (painted dark to improve absorbtion of heat) and an outer glass facade seperated by an air gap. The inner wall absorbs sunlight & heats up, so warming the air in the gap. The presence of vents at the top & bottom of the inner wall allow a convection current to circulate air between the gap and the living area; warm air passes into the house at the top while cooler air is drawn into the gap at the bottom. Notice how the need for a large energy collector has influenced the profile of the house. The bungalows are part of a sheltered housing scheme at Acorn Close, Bebbington, the Wirral, UK.