Forming a building and choosing building material, such as window glazing and insulation, along with ventilation arrangement can highly influence comfort and energy efficiency of a building. To be able to give the best consultation, Lagnatækni is equipped with the latest software for building moduling and energy calculations. Both outer and inner loads can be simulated for a building to help choosing the right glazing material and other building material. This loads can be seen on a yearly basis and influences the sizing of HVAC systems concerned. This approach is a good addition for analysing complex buildings and complements well with all the experiance within the company in this field.