The energy impact of envelope leakage. The chilean case

Improving the airtightness of housing is an issue that concerns the Chilean state. Building ordinances do not currently include any requirement to limit infiltration and its associated energy loads. This situation affects the energy and environmental performance of housing, and has economic and social consequences of great importance for inhabitants and the State. This text presents part of a research project commissioned by the Chilean Ministry of Housing and Public Works, with the aim of defining acceptable airtightness standards for buildings by territorial zone in Chile. The results are presented of a baseline study intended to measure the impact of infiltration on the energy demand for the thermal conditioning of dwellings in Chile. Using pressurization techniques, air tightness was measured in a sample of 185 dwellings built in 2007 and 2010, which is representative of more than 95% of the construction carried out in those years in the 54 provincial capitals of Chile. The LBL model was used to link airtightness properties of dwellings with climate variables in each of the provinces to obtain standardized coefficients of infiltration. Finally, with the dynamic simulation software TAS, energy loads due to infiltration and total energy demand were measured by building type and province. It was concluded that the energy loads caused by infiltration in Chile vary significantly and have different effects depending on the type of energy demand. In particular, in the sectors with predominant heating needs, air infiltration generates demands of between 23 and 203 kWh/m².year, and can represent between 20 and 50% of the total energy demand for thermal conditioning. Also, it was confirmed that in the country's current state of development, an important step in the energy improvement of the building stock necessarily lies in the improvement of its airtightness characteristics.