Passive house in Lithuania: long-term monitoring results analysis

Abstract

The Passive House (PH) algorithm, developed in Germany, is the world’s leading standard for energy-efficient construction and is the basis for the design of Passive Houses. The Passive House Planning Package (PHPP) models and certifies them. According to the Lithuanian national certification system, Passive Houses certified in Lithuania are A+ or A++. In Lithuania, NRG Pro is used for the design process, and NRG-sert is used for the energy performance assessment of the designed building and the certification of the constructed house. This study focuses on the data collected since 2015 on ambient air and indoor temperature changes, measured by the weather station, monitoring of ventilation, heating, and hot water energy consumption, measured by electricity meters, for the first single-family residential building in Lithuania, built in Vilnius and certified by the German Passive House Institute. A comparison is also made between the actual performance of the building and the results obtained by the modelling software PHPP and NRG-sert. The study shows that a building certified to the PN standard has excellent long-term performance, which is close to the results predicted by the PHPP certification. In contrast, the data reported in the national certification differs from the monitoring results obtained sometimes. One reason could be that the PHPP algorithms are continuously improved and are based on active monitoring and analysis of monitoring data since 1990. In Lithuania, NRG-pro and NRG-sert are updated only to comply with legal requirements. To date, no building has been formally tested to confirm that its calculations correspond to the actual energy performance of buildings. Passive Houses, which started to be built in Lithuania more than ten years ago, are still keeping pace with, and often significantly outperforming, most of the houses built in the country today in terms of energy efficiency and comfort. It is necessary to establish the consistency of the modelling and certification programs used in the national certification system with actual performance. To this end, it is necessary to start audited long-term monitoring of buildings of different energy performance classes and for different purposes, to establish the relevance of the modelling and certification tools used in the national certification system to the actual performance, and to improve these tools continuously.