Some final random thoughts about Germany, from a German-descended Australian who's visiting his German wife's family.
Housing
Every German home I've visited is essentially airtight.
The doors aren't just a rectangular slab like ours, they have a proper lip around the edge and they seal very well against the frame.
The windows are the same. They also have two ways of opening, depending on how you turn the handle.
If it points up, the window hinges on the bottom, opening along the top - this allows some air through without allowing rain or thieves into the house.
If the handle points down, the window hinges along one side, opening like a door.
It gives you total control of the airflow through the house. And in the cold winter, it keeps the warm air trapped very effectively inside.
Germans also make better use of their suburban space, as virtually every house is multi-storey with a basement underneath.
There's just something very cool about having a basement! It's the shed you don't have to leave the house for.