In most of countries the energy performance of buildings is defined as (primary) energy use of whole building's (heating, cooling, ventilation, DHW, lighting, HVAC auxiliary, appliances), not as specific requirements for building envelope. For construction companies of production of modular renovation panels it in necessary to know heat loss properties of building envelope (U, W/(m2K); 'P. W/(mK): x. W K; qso, m3/(hm2)). In this study it is analyzed what kind of heat loss requirements exists for building envelope to meet on annual basis to following targets: nZEB i.e. national nearly zero energy definition; deep energy renovation with 80 % reduction of primary energy; ZEB i.e. net Zero Energy Building = the annual primary energy use = 0 kWh/(m2 a). Indoor climate and energy calculations were made based on national energy calculation methodologies in six countries: Denmark, Estonia. Latvia, Czech Republic, Pormgal, and Netherland. Requirements for heat loss of building envelope vary depending Ofl requirements on indoor climate and energy performance in specific country, outdoor climate, availability of renewable energy, and building typology. The thermal transmittance of the modular wall panels for nZEB was 5% from prc-renovation thermal transmittance in Latvia, 10% in Estonia and up to 50% in Portugal. For roof the decrease of thermal transmittance was smaller mainly due to smaller thermal transmiftancc before renovation. Results show the difticulties to reach ZEB with multi-story apartment buildings in cold climate. There arc not enough places to install rcnewablcs for energy production on site