The second article doesn't mention no heating at all, from the little I know some heating is necessary. > Each of the Växjö highrises also has a ventilator in

The second article doesn't mention no heating at all, from the little I know some heating is necessary. > Each of the Växjö highrises also has a ventilator in the attic that transports the human-generated heat back into the apartments Heat recovery systems are very popular even in non-passive houses, combined with Ground source heat pumps and decent isolation you get excellent results and low costs for heating and as the article says the bigger problem is cooling in the summer as many houses are built facing sun-wards to catch more heat in the winter.