The urgent demand for buildings due to the economic development has lead to some impressive and remarkable pieces of architecture. A large number of architects influenced by their domestic regional points of view designed and planned new projects. Doing this nobody paid attention neither to the different climatic boundary conditions in the different climatic regions of the world nor to the available and special building materials.


In addition it must be pointed out to the problem that very often buildings are planned without any functional important details of the construction. Details such as sufficient moisture proofing or an adequate drainage for the roof and the front are not considered. Furthermore people do without a heat insulation that would be necessary because of the weather or without a 100% airtight building envelope.


The negative consequences of a method of building done fast and under pressure show major weak points as far as the planning- and building quality are concerned. Furthermore, the scope of energy-saving heat insulation is not taken into consideration or it cannot be taken into consideration because of missing pragmatically used computer models.


However, the energy-saving heat insulation is tremendously important because it finally helps to reduce the usage-depending necessary expenditure of energy of the heating and cooling to an economically acceptable extent. An important condition for this is a planning of the envelope especially of the building façade according to the necessary requirements.


LEC as a planning- and controlling organization including a certification system is able to resolve these difficulties. The energy certificate for buildings enables both the architects and the approving authority with average knowledge and an economically acceptable expenditure to understand and to evaluate the energetic reactions of buildings. So it reflects the energetic quality referring to the heating and cooling relative simple but still relative exactly.

While doing this, it is important that the examination of the buildings exclusively results from the physical basis with regard to the regional climate conditions. The calculations are exclusively based on the results of the thermo-technical balance equation and the evaluation is carried out without any influence by political and lobbying parameter.


The Estimation Program LEC

LEC (Low energy Certificate) is a planning tool to evaluate the energetics of buildings. The programme was developed by the BBS INSTITUTE led by Prof. Dr.-Ing. Hans-Peter Leimer in cooperation with the Hefei University (Anhui/China) and the University of Applied Sciences and Arts, HAWK (Hildesheim/Germany). The development was completed by the support of and cooperation with econet (China) and PKPM (China).


Thanks to the evaluation programme it is possible to evaluate nearly all building types and parts of a building with regard to their energetic quality separately after the heating period and after the cooling period.

The examination of the buildings with regard to the regional climate conditions is based on a pure physical basis. In this context it is important to mention that the calculations are exclusively based on the results of the thermotechnical balance equation.


The basis for the evaluation of the heating period is a comparison with reference buildings that were in accordance with the method of building according to the standard of the 80ies paying attention to each climatic region.

As far as the cooling periods are concerned, the evaluation is based on comparisons with an optimal façade defined as "cooling-energy neutral".


The evaluation of the need of energy for cooling and heating are re-evaluated, classified and shown with regard to certain criteria. The result of the energetic verification is presented with a simple star system. An increase of stars clearly shows the energetic quality of the building, which means that the user can immediately recognize the energetic quality of the building thanks to a simple illustration.


Weitere Informationen unter www.lowenergycertificate/download