Starting from the year 2021 all new buildings will need to be zero energy therefore increased attention must be paid to ways how to reduce the energy consumption of buildings. The zero energy level can only be achieved by consuming very small amount of energy for heating, ventilation, electricity and hot water so this necessary energy can be produced by renewable sources. Therefore these buildings will be similar to today’s buildings of passive house standard. The paper provides conclusions about what should be the necessary thickness and heat transmission coefficients of insulation for opaque elements - exterior walls, ground slabs and roofs as well as the optimal sizes of the windows, their orientation and heat-technical properties to achieve passive house standards in Latvian climate. Also the paper presents economical estimation and payback time calculation of zero energy building constructions and engineer technical systems in Latvia.