A comparison of the energy consumption in two passive houses, one with a solar heating system and one with an air-water heat pump

Detailed measurements of the auxiliary energy consumption for space heating and domestic hot water preparation in two detached passive houses south of Oslo are reported for the full year 2013. The study compares two equal, new built houses heated with different technologies, one by solar thermal heating and the other with an air-to-water heat pump. The houses are built by central actors from the building industry with high potential of being representative for a sizable, new-built housing stock rather than with focus on system optimisation. The results show that the need for additional energy, corrected for differences in domestic hot water consumption and indoor temperature, is 15-20% higher in the heat pump heated house than in the solar heated house. However the general energy consumption exceeds significantly the dimensioned figures for passive houses in Norway. The measurements demonstrate that solar thermal heating is competitive with heat pump technology even at high latitudes under Norwegian climate even in the case of a non-optimised system. With the available data potential heating system design improvements were pointed out. (C) 2015 Elsevier B.V. All rights reserved.