The Impact of Input Data on the Building Energy Performance Gap: A Case Study of Heating a Single-Family Building in Polish Conditions

This work deals with the performance gap between prognostic models of the energy needed for heating and actual energy consumption based on measurements. An in-depth case study is presented for a real single-family building, taking into account physical calculation models (monthly and simple hourly method according to the Polish methodology based on standard EN ISO 13790) and relevant input data. The hypothesis is confirmed in that it is possible to achieve high convergence between actual energy consumption and the calculated energy need when taking into account the high-quality input data obtained using relatively simple measurement methods. The results indicate the impact of key input data on the computational energy needed for heating. For the case study considered, the greatest influence is caused by the introduction of actual internal heat gains. Entering only some of the actual data may yield a result that is farther from the actual value than a result based only on standard data. This article provides knowledge that leads to the development of a “new consumption method” using physical models in combination with available high-quality input data, which helps change regulations and increase the significance of energy performance certificates in Poland.