The European Parliament Buildings Directive (EPBD) obliges Sweden to develop plans to enhance the amount of NZEB. Define what NZEB for them exactly constitutes - technical definitions and system boundaries for energy performance calculations. The National Board of Housing, Building and Planning in Sweden has received an assignment from the Swedish government to propose the definition and quantitative approach on energy requirements for NZEB. NBHBP suggest the system boundary should be the delivered (bought) energy. The delivered energy divide into two different energy form. The set system boundary to calculate the specific energy performance with the introduced weighted factor. Makes it possible to compensate the specific energy performance by using renewable energy generators on site. The risk is inefficient buildings can use renewable energy technologies on site to compensate the delivered energy to achieve the 80 kWh/m2, year (the proposed energy requirements for NZEB). This results to high energy cost along with large investments in renewable technologies on site, or the need to add fossil fuels to make up the high-energy demand. The both reference houses Circuitus and Bright Living are NZEB, per the Swedish definition proposal of NZEB from NBHBP. The most significant difference is Circuitus has better heat exchanger and building envelope than Bright Living.