Geothermal Energy (the energy extracted from heat stored in the earth) is one of the most environmental-friendly and cost-effective energy resources in use and has the potential to help mitigate global warming if widely deployed in place of fossil fuel. Technological advances have dramatically expanded the range of viable resources, especially for applications such as home heating & cooling, opening a potential for widespread exploitation. This is particularly true for the LOW-ENTHALPY power generation utilizing GCHP (Ground Coupled Heat Pumps). Despite the EU - through the RES Directive (2009/28/EC) and Directive on the Energy Performance of Buildings (2010/31/EU) - tackles directly this issue of promoting the use of renewable energy sources (to reduce environmental pollution coming from fossil fuels and to boost near-zero CO2 energy demand and carbon neutrality principle among the Member States and EU Candidate Countries), some endogenous factors and market barriers – that are present also in the Adriatic area - hamper the deployment of low-enthalpy geothermal energy, such as the lack of harmonized regulations at the national / regional level regarding heating & cooling permissions and insufficient information (among policy and decision makers, stakeholders) on applicability prerequisites, cost-benefit calculation, lack of demonstrative successful examples and reliable statistics on the RES H/C applications. Upon these premises, the overall objective of LEGEND, coordinated by the Province of Ferrara (a key-actor in the geothermal energy in Europe), is the promotion of energy efficiency concepts and low-enthalpy geothermal energy benefits in the Adriatic area through the development of demonstration cases all over the cooperation space in public & residential buildings utilizing GCHP (Ground Coupled Heat Pumps) as well as the development of cost/benefit monitoring activities and policy & financial supporting schemes. Therefore, the project carries out an assessment of the technological, environmental and economic key-factors (supported by a Life Cycle Assessment analysis) to address practical applications with high transferability potential in 7 countries & 11 regions of the IPA Adriatic area and public - private partnership models to facilitate the diffusion and use of geothermal technologies. Since one of the challenge tackled by LEGEND is to show the potentialities of GCHP technologies & convince policy makers and stakeholders on the geothermal energy positive trade-off to push invest in this renewable energy sector, the rehabilitation of 10 public buildings sizing 300-500 square meters (school wing , such as the gym or public offices), frequently visited by people (tot: 5 in Italy, 2 in Croatia, 1 in Albania, 1 in Montenegro, 1 in Bosnia Herzegovina) is developed. Additionally, 3 pre-investments analysis that refer cost/benefit for the introduction of massive GCHP investments are developed in highly populated and CO2 high emission areas fitting with GCHP purposes. The immediate results of the energy-rehabilitations, to be achieved during the project, is the reduction of 295tons of CO2 per year; 144 toe/year renewable energy production triggered; 132 toe/year primary energy saved. At governance level, the main results are 1 final political memorandum addressing a roadmap to boost the diffusion of the low enthalpy geothermal energy in the Adriatic and one Recommendation Papers per every concerned area to simplify and clarify the normative regional platform for GCHP deployment. Target groups (targeted by a strong dissemination campaign and trained through capacity building seminars) are (a) regional and local authorities concerned in the energy management of residential districts & industrial sectors; (b) stakeholders, energy managers operating in RES sectors and technicians of energy provider companies (c) builders/property owners and house yard, architects and engineers associations. LEGEND duration is 24 months