The project Energy efficient construction in cold climate is a study of six newly produced low energy buildings in the region of Umeå. Four buildings are houses and two residential buildings which are located from Sikeå up north to Nordmaling down south.
The buildings have been equipped with wireless logger system for collecting data of energy performance for the entire building and for individual components of the energy system. Loggers for relative humidity and temperature have been placed in ventilation and the buildings construction shell. The later of the position of loggers have been placed in different depths of the constructions isolating shell.
The purpose of this study is to investigate these buildings energy performance and what risks constructing energy efficient buildings in cold climate due to humidity. The relative humidity and temperature sensors located in the construction shell show no signs of risk for rotting and mold. Moisture migration is a slow process and to be certain longer measurements are required.
With the method called energy signature the measured energy usage have been normal corrected by year and the average U-value calculated. Expected energy usage and average U-value is compared to our measured data in this report.
Two buildings in the study are equipped with a buried pipe for supply air which is 36m and 10 m long. The longest (36m) shows a big increase of air temperature (from -25°C outside to +°2 at the inlet connecting to the heat exchanger). This by means no extra heat is required for the inlet air to reach comfortable temperature.
The measurement of energy displays that constructing buildings with lower energy use then the Swedish Boverkets requirements are confirmed. The houses shows a specific energy usage as Boverkets definition (energy for heating and for domestic hot water per heated surface area) from 59.7 to 91.8 kWh/m2, year and the residential buildings from 68 to 75.5 kWh/m2, year which are lower than today regulations at 130 kWh/m2, year and 95 kWh/m2, year for electric heated.