Impacts on Indoor Thermal Comfort and Heating Energy Use in Hellenic Dwellings from Occupant Behavioral Reactions

Abstract

In an effort to reduce the operational cost of their dwellings, occupants may even have to sacrifice their indoor thermal comfort conditions. Following the economic recession in Greece over recent years, homeowners have been forced to adapt their practices by shortening heating hours, lowering the indoor thermostat settings, isolating spaces that are not heated or even turning off their central heating system and using alternative local heating systems. This paper presents the results from over 100 occupant surveys using questionnaires and walk-through energy audits in Hellenic households that documented how occupants operated the heating systems in their dwellings and the resulting indoor thermal comfort conditions and actual energy use. The results indicate that the perceived winter thermal comfort conditions were satisfactory in only half of the dwellings, since the actual operating space heating periods averaged only 5 h (compared with the assumed 18 h in standard conditions), while less than half heated their entire dwellings and only a fifth maintained an indoor setpoint temperature of 20 °C, corresponding to standard comfort conditions. Mainstream energy conservation measures include system maintenance, switching to more efficient systems, reducing heat losses and installing controls. This information is then used to derive empirical adaptation factors for bridging the gap between the calculated and actual energy use, making more realistic estimates of the expected energy savings following building renovations, setting prudent targets for energy efficiency and developing effective plans toward a decarbonized building stock.

The impact of building occupant habits on heating energy consumption: a case study

“…Whether it is a temperature higher or lower than the standard temperature, the large variability between users is also noted by researchers from Greece [3], England [5] or China [9]. Therefore, for professionals involved in identifying solutions to increase the energy performance of buildings, the variation of indoor temperatures within such extensive limits becomes an uncertainty in determining the actual energy consumption for heating.…”

“…Increasing the energy efficiency of buildings is a key point in reducing global warming, and to achieve this, efforts must be made by all professionals involved in the building sector, but at the same time, building occupants have an important role to play. Several authors [1][2][3][4][5] note that the behaviour of occupants directly influences the energy consumption in buildings. Considering this influence and that in European Union, in 2019, 64% of final energy consumption in the residential sector was generated by heating of the spaces [6] it can be said that, some significant reductions in consumption can be made with a better understanding from the occupants, on how they can participate in reducing the total energy consumption.…”

The Impact of Energy Renovation on Continuously and Intermittently Heated Residential Buildings in Southern Europe

“…Either intermittent heating habits or the absence of heating are common in Portugal due to warm climate conditions, low incomes and expensive energy costs, as well as some cultural contexts and rooted habits [29]. In Greece as well, to reduce the operational costs, most of the residential building owners use their space-heating systems for only 3-4 h per day [30]. Correspondingly, the lower limit of acceptable indoor temperatures during the heating season in southern European countries is lower than that in Nordic countries.…”