No abstract

No abstract

Abstract:In order to fulfil the European Energy Performance of Buildings Directive (EPBD) requirements for the reduction of energy consumption, European national requirements have been created for building envelope thermal properties and calculation methodology to determine if building energy efficiency is created. This is however not true in all methodologies. The necessity of building air tightness appears only for new A class buildings, and there are no requirements for air tightness for other building classes. Therefore, the aim of this work is to improve the methodology for the calculation of energy efficiency of buildings, while taking into account the air tightness of the buildings. In order to achieve this aim, the sum energy consumption of investigated buildings was calculated, energy efficiency classes were determined, air tightness of the buildings was measured, and reasons for insufficient air tightness were analyzed. Investigation results show that the average value of air tightness of A energy efficiency class buildings is 0.6 h −1 . The results of other investigated buildings, corresponding to B and C energy efficiency classes, show insufficient air tightness (the average n 50 value is 6 h −1 ); herewith, energy consumption for heating is higher than calculated, according to the energy efficiency methodology. This paper provides an energy performance evaluation scheme, under which performed evaluation of energy performance of buildings ensures high quality construction work, building durability, and the reliability of heat-loss calculations. OPEN ACCESSEnergies 2014, 7 4973

thermal bridges make only 3 % of overall heat losses through envelopes, it is 122 kWh/m² per year. According to results of the analyse general specifications were made for designing building envelopes of "A" energy efficient class: _ The building of "A" class can be designed using ordinary solutions of linear thermal bridges, bigger heat losses through thermal bridges can be covered by increasing thickness of thermal insulating layers and using windows of better thermal behaviour but as a result the costs of building house increase too._ When effective solutions of linear thermal bridges are used, the same energy efficiency of the building can be reached using less thermal insulating layers, windows and doors of less thermal behaviour if the building of better energy characteristics is designed.

No abstract