A comparative life cycle assessment of a cascade heat pump and a natural gas furnace for residential heating purposes

A cascade heat pump is proposed as an environmentally friendly alternative to natural gas heating systems used for space heating in the residential sector. A comparative life cycle assessment of a natural gas furnace and a cascade heat pump was conducted to show the reductions in environmental impacts, such as global warming potential, energy used, and cost savings. The analysis used environmental data from 2020 for Toronto, Ontario, Engineering Equation Solver, and Sustainable Minds. The results of this comparative assessment demonstrate that implementing a cascade heat pump for heating purposes reduces the global warming potential by 85.4% when compared to a typical natural gas furnace. Moreover, the negative impacts on human health are reduced in every category. Specifically, the factors that can cause harm to human respiratory systems are decreased by almost 10 times when using the cascade heat pump as an alternative heating system. This is important since such systems are used in high density residential areas where the impact on human health can be far greater. Lastly, it is found that the highest CO₂ -equivalent emissions are released during the usage life cycle stage in both heating systems at 18 883 kg of CO₂ -equivalent, and 104 CO₂ -equivalent for the furnace and heat pump, respectively. The cascade heat pump releases approximately 1% of carbon emissions than the emissions released by currently used heating systems, which are natural gas furnaces. Integr Environ Assess Manag 2022;18:572-580. © 2021 SETAC.