No one I have talked to pays attention to the 120kwh/m2 only to the 15kw/m2 and if you can get to this level, the biggest load in the house becomes DHW.
I brought this up because I am working on a 3 floor, 380m2 passivHaus and we are struggling to select the heating system. The owners are leaning towards radiant tubing and 40mm of thermal over pour (gypcrete) even though it is a high cost for very little heat output. It does, however, make the heat very even and has other benefits (sound and fire).
The option to this is at least 6 heads of ductless (although we have gas on the street, we are not having gas in the house) and an ERV made by Air Pahoda, currently the most efficient one on the market. The ERV was delivered a couple days ago.
As we know multi head units are not as efficient as single head units so if we went this route, there would be a lot of infrastructure. so the option is to have one larger heat pump heating a water tank for both DHW and the floors. Total heat and cooling loss is estimated at 7kw (24Mbtu).
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