In addition, since the start of 2009, new builds – and in some instances also larger extensions and renovations – have had to cover a part of their energy demand for heating, hot water and cooling from renewable sources. This requirement is enshrined in the Heat Act (Erneuerbare-Energien-Wärmegesetz, or EEWärmeG), Germany´s implementation of the corresponding EU Directive.
With the introduction of EnEV 2009, the maximum permitted upper limit for consumption of primary energy on heating, ventilation and cooling (in non-residential buildings also for built-in lighting) has been brought down by 30 per cent. Parallel to this the requirement for thermal insulation for the building envelope has risen by around fifteen per cent. Stricter requirements regarding thermal insulation also now apply to renovation and modernisation projects. The lower threshold has also changed: anyone replacing or renovating the outer envelope of a building (external walls, windows, roof) must observe EnEV 2009 if the area affected by the measure in question exceeds ten per cent of the entire area of that particular component in the building. Previously, under EnEV 2007, this lower limit had been twenty per cent, and it had referred to the total area for that particular component with the same orientation in the building as a whole. To illustrate this change, up until the start of 2009 anyone renovating less than one fifth of the wall area of a north facade was not obliged to meet the requirements of EnEV 2007. But now, however, any renovation project that involves over one tenth of the entire external wall area, regardless of orientation, has to observe the stricter requirements of EnEV 2009.
The requirements of EEWärmeG 2009, in force since the start of the year, are not entirely new. But what has changed is the EnEV standard to which EEWärmeG refers developers who do not wish to use energy from renewable sources. In this case their alternative is to achieve fifteen per cent more efficiency than that set out in the EnEV requirements.
In the case of new residential buildings, the methodology behind EnEV has changed: The annual primary energy needs of the planned house, as calculated in advance, may not exceed the values calculated for what is known as the “reference house”. This reference house has the same geometry, usable floor area and orientation as the planned house. The technical details regarding the finished result, i.e. thermal transmittance of the individual components in the building envelope and values for air-tightness and building installations in the reference house, are to be found in Annexe 1 to EnEV 2009 (Requirements for residential buildings).
The subject of renewable energy now has to be addressed by architects and developers of all buildings, whatever the size. EnEV 2007 only stipulated that renewable energy sources should be investigated for large buildings, with over 1,000 m2 of usable floor area. This limit has now been dropped and in EnEV 2009 the use of renewable energy is now taken into account in the reference building.
In its energy efficiency legislation, the German government is pursuing a policy of both tightening requirements while also offering financial support and incentives. In the context of EnEV 2009 the programmes offered by the KfW banking group are relevant. In April 2009 the KfW Förderbank reorganised its promotional programmes to align with the tighter EnEV standard for 2009. In the new KfW “Energy-Efficient Construction” programme, for example, the standard in future is the “KfW Efficiency House 55/70”. Here, special low-interest loans are available for new houses that are targeted to achieve only 55 or 70 per cent of the level of energy consumption permitted for new builds under EnEV 2009.
