U.S. Department of Energy Solar Decathlon is a university competition in the field of sustainable solar architecture. Student teams are challanged to design, build and operate energy self-sufficient solar-powered houses. Buildings are judged in 10 competition disciplines. The winner is the team that best blends affordability, consumer appeal, and design excellence with optimal energy production and maximum efficiency. The CTU team enters the competition with the "AIR House", whose goal si to have a minimum environmental impact throughout the whole life-cycle of the building and to have positive influence on the life quality of its inhabitants. Since it is rather difficult to estimate building thermal performance of well insulated building where gains and losses are similar large numbers, and even more difficult to estimate it for two different climates (LA for the competiton and Czech for the succeeding building operation), variant energy analyses were performed to help with the design and decision making process. This paper provides these energy analyses and their results with their impact to the AIR House design.