In the early days of energy conservation (1980s) several countries took the need for energy efficiency seriously enough to sponsor some demonstration buildings. For instance, a US university design concept was built in Regina, Canada in1978. The Saskatchewan Energy Conservation house [1s] 4 demonstrated a new, passive technology. It had super-insulated and airtight walls, large windows on the south facade, evacuated solar pipes for domestic water heating, and a heat recovery ventilator. Despite of all the technology demonstrated there, as Bomberg et al [2] explains, the passive measures were not accepted in the Canadian marketplace because the builders modified the heating system and thereby changed the air flow pattern in the house.