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The paper presents significant aspects regarding the concept and details of constructive solutions used to design and implement an energy efficient school building in Romania. Although the site is in a moderate seismic zone, the structural needs of the building impose specific insulation solutions for making the passive house concept applicable. Renewable energy sources are also applied to optimize the maintenance cost and to reduce the payback period to a feasible level. In order to prove the benefits of the solutions, to justify the higher initial investment, to improve the real-time energy consumption of the building, as well as to keep track of the internal climate parameters, a complex monitoring system was planned and implemented. Details and correlation between specific details and temperature sensors distribution are also presented.

The European Union set ambitious targets to achieve climate neutrality by 2050, and one of the measures taken towards this goal was the implementation of nearly Zero-Energy Buildings. Despite the commitments of the EU member states, many householders and investors had a disposition to incredulity regarding the energy efficiency of the buildings due to the higher cost of the investment and the relatively long payback time. However, at the end of 2021, the energy crisis significantly rewrote the circumstances, and energy prices and the costs of construction materials began to rise. In this situation, it was necessary to reconsider the importance of energy efficiency for buildings due to the maintenance costs. This article aims to assess changes in payback periods over the past 13 years and conduct life cycle cost evaluations by comparing energy-efficient residential buildings with traditional houses. The analysis considers variations in construction materials and labor costs in Romania, as well as energy price changes during the building’s operational phase. Through these methodologies, it has been demonstrated that the implementation of energy-efficient buildings offers a cost-effective solution already in the medium term, providing incentives for investors and future houseowners to reduce their dependence on energy and pursue long-term decarbonization.

This paper presents the design and monitoring scheme of an energy efficient high school building with emphasis on the analysis of constructive and geometric thermal bridges that can affect the overall energy consumption and thermal comfort. The ANTHERM software is used to accurately assess the specific details and determine isotherms, heat flux distribution and the Psi-values (Ψ value) of the sections where different types of materials connect. A monitoring system with temperature sensors installed in the layers of the building envelope elements has been designed in order to compare the obtained values with the real time thermal performances of the envelope elements. The study highlights the influence of the type and thickness of the insulation materials used in the specific constructive details on the overall thermal performance of buildings.

The paper presents details regarding the implemented monitoring system of heat loss, interior comfort and energy consumption particularities of an energy efficient school building in Romania. Despite the fact that there is an emphasis on energy saving and sustainability in the building industry legislation and policies, there are still too few examples of good practice at local level. Recent trends have brought changes in how designers solve specific details like thermal insulation thicknesses and use of renewable energy but further improvement is required for a more detailed understanding of the entire building's energy balance behaviour both on overall and specific details level. Therefore, a complex monitoring system was built in a carefully designed and constructed school building in order to collect relevant real-time data of every specific part of the thermal envelope, the HVAC systems and interior comfort parameters. The main purpose of the system is to highlight the order of magnitude of the differences between the design and the real-time values of the most significant parameters, the importance of each detail and also the need of further research development in this field.