Operating costs comparison of heat pump vs condensing gas boiler for the residential heating service: an Italian case study
The determination of the running costs of a heat pump is essential to communicate the convenience of its use in place of fossil fuel systems. Such a calculation is the topic of many studies and analyses, usually based on projections of the trend of final tariffs without any subsequent checks. This work proposes a case study in which this gap is filled, presenting a study to calculate the expenditure incurred for heating a residential home in an average climatic zone in Italy during the last seven heating seasons and comparing it with the expenditure that would have resulted for the same service using a commercial heat pump. The methodology for calculating operating costs is illustrated, starting from those sustained with a condensing gas boiler and calculating, with a simplified model and suited assumptions, those that would have occurred with a commercial air-water heat pump operating in the actual climatic conditions during the same heating seasons. The results show a strong dependence of expenditure on the ratio between the two commodities, gas and electricity, with differences in single seasonal expenditure spanning a range between -51% and +12%, due to the occurrence of unpredictable phenomena such as those that occurred with the pandemic and energy crises. As a whole, in the seven years analyzed, a global saving in operating costs of approximately 32% was calculated, which must be taken into account in the analyses for the convenience of a heat pump compared to a fossil fuel system.