Solar thermal systems

Of the 20 projects 14 have active solar thermal systems. Ten systems are for domestic water heating (dhw), four are combined systems also contributing space heating. On average, the houses with solar dhw heating have 5 m[18] of collector coupled to a 500 liter storage tank.

The four houses with combined dhw and space heating systems have an average of 12.5 m2 of collector coupled with 2200 liter of storage. Two of those buildings have high efficiency vacuum collectors, which explains the smaller collector area per storage tank volume.

Conclusions

In planning a high performance house for the first time it can be useful to observe which design characteristics occur frequently in successful projects. Of particular importance are the key parameters of compactness, wall and window U-values, window to facade ratio and air tightness. The resulting very low remaining space heating requirement makes the energy needed for domestic water heating also an important end-use. Three quarters of the houses reported here have a solar energy dhw or combined dhw and space heating system to further reduce the consumption of non-renewable energy.