The Allard solar dome house is a passive solar structure with an active solar back-up. The house is a dome shape to minimize the surface area, which in turn minimizes heat loss.
Passive solar heat gain is through the huge south-facing window array. Warming sunlight enters the house and heats the abundant thermal mass for flywheel-like stability. The house is slow to heat-up, and slow to lose heat.
The window shade system prevents overheating during summer days and prevents radiative heat loss on winter nights.
The active solar back-up system consists of a trickle collector garage roof which drains its hottest water directly into a huge basement storage tank. When required, this hot water is pumped through the heat exchanger to give its heat to the circulating air.
An Allard dome costs significantly less to build than a conventional structure of comparable size because it uses far fewer materials due to the efficiency of its spherical shape. Also, the factory-prepared components are quick to assemble and perform multiple functions. Struts are the framework and also serve as window frames and interior trim.
A strut kit for the Model 130 dome (42.6 ft. in diameter) encloses 1,427 sq. ft. per floor for $23,200. It is self-supporting and can be assembled in less than a week by unskilled labor.
A Model 85 dome kit ($12,700) is 28 ft. in diameter and can be assembled in a single day.
Obviously, the way in which interiors are completed varies according to personal taste, so there is no set price.
However, the advantages of an Allard dome make it an attractive and cost effective solution to family housing.