Early 2009 Sonderborg became the first city in Denmark to build a house that produces more energy than its family consumes in their everyday life.

The house has a positive annual energy costs and sells the excess power to the national grid at the market price – the same price the consumers pay when they buy the power from the grid. The meter simply runs backwards!

The success of the house is based on a combination of energy efficient insulation, ventilation, passive solar heat, geothermal heat pump, photovoltaic and an ultramodern energy management system constantly monitors and optimizes the use of energy.

The Danish Building Code for 2020 will be based on the same passive house construction with a renewable energy production.