The document describes 18 different residential and commercial buildings in Greece that utilize various combinations of heating systems including heat pumps, gas or oil boilers, solar thermal panels, and fireplace boilers. The systems are described along with their installation details such as installed capacity, heated area, year built, and building type. Locations include Korinthos, Kinetta, Thessaloniki, Paros Island, Alexandroupoli, and Chalkidiki. Heating system combinations include heat pumps paired with boilers, solar thermal, or both.