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.