Energy and Buildings 132 (2016) 74–90 Contents lists available at ScienceDirect Energy and Buildings j ourna l ho me pa g e: www.elsevier.com/locate/enbuild Modeling energy refurbishment scenarios for the Hellenic residential building stock towards the 2020 & 2030 targets Elena G. Dascalaki ∗ , Constantinos A. Balaras, Simon Kontoyiannidis, Kalliopi G. Droutsa Group Energy Conservation, Institute for Environmental Research & Sustainable Development, National Observatory of Athens, I. Metaxa & Vas. Pavlou, GR-15236 Palea Penteli, Greece a r t i c l e i n f o Article history: Received 30 November 2015 Received in revised form 29 March 2016 Accepted 1 June 2016 Available online 2 June 2016 Keywords: Residential buildings Building stock model Scenario analysis Energy efficiency strategies a b s t r a c t Residential buildings in Greece account for about 79% of the exclusive-use building stock and consume about a quarter of the total final energy consumption, with space heating and domestic hot water being the main energy end-uses. About 58% of the dwellings were constructed before the 80 s and the adop- tion of the first thermal insulation regulation. This paper presents the results from the Hellenic pilot action within EPISCOPE. The overall approach and analysis are based on the national TABULA residential building typology for single- and multi-family houses in order to estimate heating energy performance and savings. The work exploits Census and statistical data for defining the Hellenic building stock and empirical adaptation factors to make more realistic estimates from normative calculations. The analysis is supported by a detailed data disaggregation in terms of the number of dwellings and floor areas, based on envelope thermal characteristics, heat production units, energy carriers, use of renewables etc. The calculation results are adapted for the building types and then projected to the building stock. Numerous scenarios for different modernization rates are assessed for identifying the most promising refurbishment strategies in space heating and DHW for reaching the 2020 and 2030 national CO 2 emission targets. © 2016 Elsevier B.V. All rights reserved. 1. Introduction Over the past decades, the buildings sector has been at the cen- tre stage of European energy and environmental protection policy actions and regulatory measures. This is well justified since build- ings in the European Union Member States (EU-28) consume about 40% of the total final energy consumption and are responsible for 36% of the CO 2 emissions in the EU [1]. Specifically, residential buildings dominate the existing building stock, representing about 75% of the 25 billion m 2 in the EU [2]. The EU-28 final energy con- sumption in residential buildings reached 296 million tonnes of oil equivalent (Mtoe) in 2013 [1], decreasing in absolute terms since its historic peak at 311 Mtoe in 2010, although it slightly increased by 0.7% from 2012 to 2013. Space heating is the most important end- use in residential buildings (67%), but its share has been slightly declining since 2000 [2]. Domestic hot water (DHW) ranks second with a stable share at 13% of the total, electrical appliances have climbed to 11%, followed by cooking at 6%, lighting at 2% and cooling at only 0.5%. ∗ Corresponding author. E-mail address: edask@noa.gr (E.G. Dascalaki). In Greece, the total number of buildings approaches 4.1 million [3] of which 3.78 million are exclusive-use buildings, with 79.2% residential buildings. Mixed-use buildings reach ∼330,000 of which the majority has main use as residential dwellings (77.5%). The evo- lution of final energy consumption is illustrated in Fig. 1, including the latest officially-reported data for 2013 [1]. The total final energy consumption reached 15.3 Mtoe, relatively close to that of the 1990 levels (i.e. 14.7 Mtoe), following a drop by -11% from 2012 to 2013. Hellenic buildings accounted for 36.6% of the total final energy use and reached 5.6 Mtoe, with a notable decrease by -23% from the 7.3 Mtoe in 2012. Hellenic residential buildings used 3.8 Mtoe in 2013 or 24.8% of the total final energy consumption in Greece [1]. Space heating and DHW are the main energy end-uses, i.e. 63.7% is used for space heating, 17.3% for cooking, 10.2% for appliances and equipment, 5.7% for DHW, 1.7% for lighting and 1.3% for cooling [4]. The annual average thermal energy use averages 10,244 kWh per household, of which 85.9% for space heating and 4.4% for DHW [4]. Heating oil (63.8%) remains the main fuel source for space heating. The annual average electrical energy use per household is 3750 kWh, which is mainly used for cooking (38.4%), white appliances (28.9%), DHW (9.4%), lighting (6.4%), cooling (4.9%) and space heating (3.0%). As shown in Fig. 1, the observed variations of final energy use for the residential sector are partly due to the prevailing winter http://dx.doi.org/10.1016/j.enbuild.2016.06.003 0378-7788/© 2016 Elsevier B.V. All rights reserved.