Smart readiness upgrades and economic assessment in existing public buildings: a case study from Greece

Abstract

This paper investigates the combined effect of energy efficiency renovations and smart readiness upgrades on an existing public building in Greece. Using a three-scenario approach—baseline (Scenario 1), energy upgrade (Scenario 2), and smart upgrade (Scenario 3)—the study evaluates the building’s energy performance, Smart Readiness Indicator (SRI), CO₂ emissions, and financial feasibility. Energy simulations were conducted using the national Energy Performance Certificate (EPC) software (TEE-KENAK), while smart capabilities were assessed via the European Union (EU) Method B for SRI evaluation. Economic viability was determined through Net Present Value (NPV), Internal Rate of Return (IRR), Return on Investment (ROI), and Discounted Payback Period (DPP) calculations. Results indicate that energy efficiency interventions in Scenario 2 reduce energy consumption by over 50% and improve the EPC class from E to B, with a favorable 15-year ROI of 111.95%, though it yields only a marginal increase in the SRI (9.2%). Scenario 3, which integrates smart technologies such as zonal thermostats, automated lighting, and a Building Management System (BMS), further boosts performance—achieving EPC Class A and increasing the SRI to 52.1%—but entails higher upfront costs and a longer payback period. The findings highlight the need for integrated renovation strategies that combine passive and smart interventions to enhance building functionality, reduce emissions, and align with EU climate goals.

Keywords

Buildings / Smart readiness indicator / Energy retrofitting / Techno-economic analysis / Renovation scenarios / Energy efficiency

References

[1] Apostolopoulos V, Giourka P, Martinopoulos G, Angelakoglou K, Kourtzanidis K, Nikolopoulos N. Smart readiness indicator evaluation and cost estimation of smart retrofitting scenarios—a comparative case-study in European residential buildings. Sustain Cities Soc. 2022, 82. 103921

[2] Chatzikonstantinidis K, Giama E, Fokaides PA, Papadopoulos AM. Smart readiness indicator (SRI) as a decision-making tool for low carbon buildings. Energies. 2024, 17. 1406

[3] Chatzikonstantinidis K, Afxentiou N, Giama E, Fokaides PA, Papadopoulos AM. Energy management of smart buildings during crises and digital twins as an optimisation tool for sustainable urban environment. Int J Sustain Energy. 2025.

[4] European Commission (2022) Smart Readiness Indicator. https://energy.ec.europa.eu/topics/energy-efficiency/energy-efficient-buildings/smart-readiness-indicator_en#sri-actions-and-tools

[5] European Commission (2024) Energy and smart cities. https://energy.ec.europa.eu/topics/clean-energy-transition/energy-and-smart-cities_en

[6] European Parliament and Council of the European Union (2024) Directive (EU) 2024/1275 of the European Parliament and of the Council of 24 April 2024 on the energy performance of buildings (recast). Offi J European Union

[7] European Commission (2024) Delivering the European Green Deal. https://commission.europa.eu/strategy-and-policy/priorities-2019-2024/european-green-deal/delivering-european-green-deal_en

[8] European Commission (2025) Smart cities and communities. https://digital-strategy.ec.europa.eu/el/policies/smart-cities-and-communities

[9] European Commission (2025) Climate change. European Climate Pact. https://climate-pact.europa.eu/about/climate-change_en

[10] Fokaides PA, Panteli C, Panayidou A. How are the smart readiness indicators expected to affect the energy performance of buildings: first evidence and perspectives. Sustainability. 2020, 12. 9496

[11] Giama E, Kyriaki E, Fokaides P, Papadopoulos AM. Energy policy towards nZEB: the Hellenic and Cypriot case. Energy Sources Part A Recover Util Environ Eff. 2021, 47: 5282-5295.

[12] Giffinger R, Fertner C, Kramar H, Kalasek R, Pichler-Milanović N, Meijers E (2007) Smart cities: ranking of European medium-sized cities. Vienna University of Technology. https://doi.org/10.34726/3565

[13] Hellenic Statistical Authority (ELSTAT) (2015) Building census: final results (2011). https://www.statistics.gr/en/census-buildings-2011

[14] Lagarde C, Robillart A, Bigaud D, Pannier ML. Assessing and comparing the environmental impact of smart residential buildings: A life cycle approach with uncertainty analysis. J Clean Prod. 2024, 467: 143004.

[15] Martínez I, Zalba B, Trillo-Lado R, Blanco T, Cambra D, Casas R. Internet of things (IoT) as sustainable development goals (SDG) enabling technology towards smart readiness indicators (SRI) for university buildings. Sustainability. 2021, 13. 7647

[16] Ministry of Environment and Energy (Greece) (2019) Energy efficiency in buildings. https://ypen.gov.gr/energeia/energeiaki-exoikonomisi/ktiria/

[17] Mirpadiab SK, Bagheri S. Identifying intelligent building management systems (BMS) in sustainable housing. J Fundam Appl Sci. 2016, 831175-1190.

[18] Papadopoulos P, Koukaras P, Giama E, Ioannidis D, Papadopoulos AM, Fokaides PA (2024) Enhancing smart readiness through simplified financial indicators. In 2024 9th Int Conf Smart and Sustain Tech (SpliTech) (pp 1–5). IEEE. https://doi.org/10.23919/SpliTech61897.2024.10612317

[19] Plienaitis G, Daukšys M, Demetriou E, Ioannou B, Fokaides PA, Seduikyte L. Evaluation of the smart readiness indicator for educational buildings. Buildings. 2023, 13. 888

[20] Ramezani B, Silva MGD, Simões N. Application of smart readiness indicator for mediterranean buildings in retrofitting actions. Energy Build. 2021, 249. 111173

[21] Zamanidou A, Kothona D, Fokaides P, Christoforidis GC (2024) Enhancing the Smart Readiness Indicator scheme: Methodology assessment through 20 use cases. In 2024 3rd Int Conf Energy Trans in the Medit Area (SyNERGY MED) (pp 1–5). IEEE. https://doi.org/10.1109/SyNERGYMED62435.2024.10799302

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