Free short video on how you can use this free program – Sketchup
PassivHaus or Passive House is a concept out of Germany for highly efficient homes that use little or no active heating or cooling. Europeans, as well as most of the rest of the world, use far less energy per capita than we do in the United States. The concept of Green Building and use of alternative energy is way ahead of where we are and we have much to learn from this.
From the Passive House website http://www.passivehouse.com/English/PassiveH.HTM
What is a Passive House?
A passive house is a building in which a comfortable interior climate can be maintained without active heating and cooling systems (Adamson 1987 and Feist 1988). The house heats and cools itself, hence “passive”.
For European passive construction, prerequisite to this capability is an annual heating requirement that is less than 15 kWh/(m²a) (4755 Btu/ft²/yr), not to be attained at the cost of an increase in use of energy for other purposes (e.g., electricity). Furthermore, the combined primary energy consumption of living area of a European passive house may not exceed 120 kWh/(m²a) (38039 Btu/ft²/yr) for heat, hot water and household electricity.
With this as a starting point, additional energy requirements may be completely covered using renewable energy sources.