The first thing is that you have to think about the least a year in advance.
If you build "passive", you must also be patient, because the construction times are very long.
Heating? Very clever is the one who can say what is the best energy for the future 30 years ...
But the most important thing is to have automatic heating in case of prolonged absence.
In addition, if a house is really passive, a simple 2kw electric heater is enough to keep a house at 18 ° c
coooolllll