In 2009 the first building designed according to the passive house concept was built in Latvia. The main question studied in the paper is conversion of ‘conventional’ (in terms of energy efficiency) building design to passive house standards without loosing the originally planned proportions and aesthetic, functional qualities of the building, and differences of construction process of a building that will comply with passive house standard requirements. Energy saving potential of the Passive House concept compare to building designed according the Latvian legislation is presented. First Blower door test results are oresented.