The integration of unique polyethylene heat exchanger loop underneath PV modules, to form a “Sandwich” PV/Thermal Roof Collector, the PV modules could also be substituted by alternatively roof tiles (concrete, clay and asphalt shingle) is studied. The Sandwich is designed to act as a roof element and heat resources for solar assisted heating and cooling technologies. A detailed thermal model is developed to investigate the performance of the sandwich roof unit. Engineering Equation Solver (EES) software is used to simulate the thermal performance of the novel system under Nottingham’s climatic conditions. The preliminary results show that the system could produce up to 10.5 kW of average thermal power annually employing a 30 m² of poly exchanger underneath 30 PV modules aperture area of 49 m² and maximum 8.6 kW of useful heat gain annually for asphalt shingle roof tile case. Under a typical Nottingham (UK) operating condition, monthly maximum thermal efficiencies are attained in July for each case with 20% for PV sandwich and 14.1% of peak thermal efficiency for roof tile case. Overall year round thermal efficiencies are recorded as 11.9% for PV case, and 9.4% for roof tile case, respectively.