Deliverable 5.1 developed reduced order and transient dynamic models for three GEOFIT demonstration sites, i.e. San Cugat in Spain (Section 1), Bordeaux in France (Section 2) and Galway in Ireland (Section 3). The development of these models is part of the approach to select, design and integrate the GEOFIT Enhanced Geothermal Systems / Ground-Source Heat Pumps into the building according to its characteristics. The work presented here shows the capabilities of reduced order and transient models in building performance prediction and optimisation, as well as their flexibility to be used in building retrofit.