With the purpose of meeting the set targets for 2020, the European Union (EU) has steered its policy towards the reduction of building’s energy consumption, which currently represents 40% of the EU total energy consumption. Nevertheless, the residential sector cannot disregard the
thermal comfort, which is interconnected with people’s health, welfare and ability to function. The effect of changes to buildings’ structure, materials used or appliances, should always take into account the maintenance of the indoor thermal comfort (Peeters et al., 2008). In EU, due to poor building construction, low household income and the rise in energy costs, between
50 and 125 million people are not able to ensure thermal comfort in their households (WHO, 2012). Chronic exposure to low ambient temperatures results in an adverse impact to the physiological condition of humans (Healyand Clinch, 2002).
In this work we use Portugal as case study due to its location in Southern Europe, targeted as one of the most likely climate impacted regions (Santos and Miranda, 2006). The achievement of thermal comfort is a relevant issue to be addressed, as about 24% of the population are unable to keep their house warm during the winter, the highest 5th highest percentage among the EU28 (Eurostat, 2017).
During the summer, an estimated 36% of the general population cannot keep their house cool (Eurostat, 2017), ranking second in all EU28 countries, as most residential buildings rely on natural ventilation for cooling (Barbosa et al, 2015). Simoes et al. (2016) analysed 29 Portuguese municipalities and estimated that 22% and 29% of the inhabitants are potentially fuel poor, regarding the heating and cooling needs of their homes.
The aim of this study is to determine heating and cooling energy needs and assess the energy performance gap on thermal comfort of households, as in Wilde (2014) and Callì (2016), both in heating and cooling seasons. The approach was applied throughout the five climatic zones of Portugal, ranging from the coldest, with more than 1800 heating degrees-day per year and a summer outside temperature between 20º and 22ºC, and the warmest zone with less than 1300 heating degrees-day/year and an outside summer temperature above 22ºC. All the 3092 civil parishes and near 3.8 million dwellings, occupied and of usual residence, were considered, while capturing specific details of construction, climate, average households areas for each region to support the definition of local dedicated energy efficiency policies and instruments. Current average country consumption for heating is 1.51GJ/capita and for cooling is 0.35 GJ/capita in the residential sector (INE and DGEG, 2011 and DGEG, 2017).