Energiberäkningar för passivhus- Fallstudier samt klassificering

Sammanfattning: Energy conservation is a current and expanding area in the building industry of today. The energy demands on buildings have been tightened through the years and the interest for energy efficient buildings has increased. Passive houses are one of the concepts that have emerged. New standards for energy and effect classification have been developed. Buildings are now going to be classified from how big the consumption of bought energy is. It then will become clear if the projected value for energy use is correct. This report highlights which causes there are to differences in projected value and measured value of energy use. The aim of the report is to, by own calculations, show input data that gives a more concordant value. The buildings will be classified from the calculated value of energy use. Of the passive house projects that are described in the report a deeper study, with own calculations, has been made for two projects. This study shows that the measured value is higher than the projected. This leads to that houses that are claimed to be passive houses in reality doesn´t measure up to the demands on passive houses. That the projected value is so misleading suggests that it is hard to make reasonable assumptions for input data when calculating the energy use during the design process. We have, however, by own assumptions of relevant input data shown that it is possible to come closer to the measured value if time is spent on choosing data with concern. The impact on the result due to variations in input data has been studied so that an idea of the sensitivity of the calculations can be made. This studies shows that small variations in input data such as airtightness, heat recovery, ventilation and household electricity makes quite a big difference while small variations of the U-value, which is low, doesn’t have a very big impact on the result.