Interest in energy efficiency has increased significantly in recent years. Regardless of the application area, there is discussion of how the same function can be obtained but with considerably less energy used. These ideas are also applicable to the housing sector and there has been talk of reducing energy needs created by electrical devices, hot water generation and heating. For all three functions, there are technical alternatives for reducing energy needs.

The idea behind the passive house concept is that no distributed energy whatsoever should be needed. Buildings instead are heated passively by energy from occupants, electrical appliances and sunshine, in short, a building without a heating system. Passive houses can be nearly self-heating.

Utilising passively supplied energy instead of actively distributed energy via radiators, for example, is a concept that has become increasingly common in Europe. In Germany, thousands of passive houses have been built. In Sweden, the most noteworthy example is the Lindås area, south of Gothenburg. In these terraced houses, only a small source of heat is required for heating. The installed power output is less than 10 W/m2, which is also the current definition for passive building construction in Sweden.

To achieve heating with passive heat sources of heat, heat leakage from dwellings must be minimised. For the Lindås area, heat leakage is minimised with especially well-insulated structural construction. Windows and doors are optimally insulated and nearly all heat is reclaimed in the efficient ventilation system.

What is a plus-energy house?

A plus-energy house combines a series of energy efficient components. A plus-energy house is self-supporting when it comes to heating, warm water and electricity. Electricity is produced with solar-cell panels, which minimizes the costs for the household.