Since there have been built thousands of zero energy buildings around the world based on different technologies we can talk about their real advantages and compare their efficiency to standard buildings.
In terms of future legislative restrictions and very strict energy requirements beginning from 2019, it is important to say that it is far less expensive to improve energy efficiency during initial design than it is to do so through a reconstruction. The resale value of ZEB is also connected to energy costs increase. Once the costs increase, the value of house increase too.
Another big advantage is that net zero energy buildings are more comfortable due to more uniform temperature (base on isotherm maps).
Also, reduction of heating costs, depending on the geographic location, can dramatically decrease the total costs of living in a family house.