Located at 50 Mohács Liliom Street — 3408/233 Hrszú — the only residential institution in the city — including the district of Mohács with 35 thousand people — is connected with the tasks of a state secondary educational institution and is an integral part of it. Given the number of inhabitants of the district and the sole nature of the institution performing the function, capacity utilisation can be considered to be ensured in the long term, i.e. the cost savings resulting from the investment will have a positive impact on a long-term institution. Due to the demand for secondary education in the City of Mohács, there is a long-term demand for dormitories, and due to the future changes in the vocational training spectrum, the number of pupils coming from the countryside is expected to increase due to the emphasis on butchery training, so the need for dormitories will continue to increase. In order for the building to fulfil its long-term function, it is essential to rationalise and develop an obsolete and inefficient built infrastructure that is unfavourable for environmental sustainability. Since the institution is in an outdated state from a building energy point of view, its operation imposes a significant burden on the state institution’s budget. The human resources part of the operating costs can be understood as an asset, but the cost of heating and electricity are also a significant cost element, which can be significantly reduced by the development, thus contributing to the improvement of both economic and environmental aspects. Thanks to the investment, the cost of heating of HUF 10.057.000 per year will be reduced by 58.21 %, so the annual heating cost is expected to be HUF 4.202.820,-Ft, while electricity will decrease by 22.000 kWh per year, which, calculated with a net purchase price of 46,76,-Ft/kWh, represents HUF 1.028.720,-Ft per year, i.e. a net cost savings of HUF 6.882.900 per year can be achieved through modernisation. With the above savings, the financial margin of the state’s institution-maintenance will be expanded, thus opening up the possibility for further strong developments of its own. When planning the investment, we chose the most cost-effective solution among several alternatives. The following elements will be implemented during the implementation of the selected alternative: new facade polystyrene thermal insulation with a thickness of 15 cm equipped with rolling grain thin blinding system, new footing XPS polystyrene thermal insulation with 15 cm thickness frost-resistant plinth plinning system, and new rock wool attic floor insulation in 20 cm thickness with vapor barrier wrap under it. Part of the development is the replacement of outdated wooden facade windows with plastic structure, 3 rtg glazed windows and stone wool placed between wooden spacers on high roofs, which is equipped with drywall cover. The exterior solutions of the lower side of the consoled parts of the building are thermally insulated using 20 cm thick thermal insulation. The southern and western roof surface of the building is optimal for the construction of the solar system technology, so during the modernisation, 80 * 1559 x 1046 x 46 mm solar panel systems with a total capacity of 20 kW will be installed, which would supply a significant part of the building’s electricity consumption in the future. Thanks to the development, the operating and operating environment of the secondary school college is significantly improved in the long term, thus contributing to the fulfilment of both the call for proposals, the Environmental and Energy Efficiency Operational Programme and Hungary’s EU environmental commitments and requirements.