A two-story semi-detached house in Ireland with poor thermal performance and energy rating has been identified for a deep energy retrofit. The project includes the installation of prefabricated 2D façade cladding upgrades to improve the thermal performance of the fabric and reduce thermal bridging. In addition, the building will benefit from further modularized solutions through the incorporation of a small 34 extension pod, which will be pre-fabricated and installed at speed. To complete the project, the energy systems will be upgraded and appropriate renewable technologies will be applied to achieve an A3 energy rating.