There is increasing interest in Life Cycle Design with the purpose of raising sustainability and reducing energy and material consumption. By increasing energy efficiency, selecting more suitable materials and lessening maintenance requirements it is practical to reduce life cycle cost. Conventional Heat pump air conditioners operate to effect a healthy and comfortable indoor environment. They are large consumers of energy, partly due to the need to exhaust air (with consequent energy wastage) from the conditioned building so that healthy ventilation air may be introduced in its place. Rather than drawing all the energy from community electricity and gas supplies, the designer should design these systems so they recover as much energy as is feasible from both building exhaust air and the environment. A low life cycle cost solar air conditioner design is described that obtains under peak load more than 90% of its energy from a combination of building exhaust air and insolation with a reduction in life cycle cost approaching a factor of 10. In basic terms, with a reduction of a factor of 3 in energy consumption along with a life increase also of a factor of 3 it is possible to approach a factor of 10 improvement in product life cycle cost. INTRODUCTION The imperative for society to reduce its materials and energy consumption by improving the energy efficiency and longevity of products is thoroughly detailed in [5, 6 and 22]. This paper presents the case that some functional products have very large scope for improvement, by way of its example of a particular type of air-conditioning system. The concept of “Factor 10” as outlined in  has far reaching implications relating to the environmental damage to the planet being caused by the combination of increasing population, materials and energy consumption and release of environmentally damaging products. “Factor 10” requires that humans immediately take actions to improve our products and processes by a factor of 10 in order to avoid disaster for future generations. In a commercial environment, consumers are highly influenced by cost, particularly initial cost. The system presented in this paper was novel in 1970 and has demonstrated very large savings in energy consumption in several hundred installations. In addition the installations of the system have demonstrated longevity benefits in the years since. Despite these benefits it has not reached the status of having widespread recognition.