This rapid review identified two results extracted from the eight studies (published between 2013 and 2018) that fulfilled our inclusion criteria. Firstly, our analysis identified five common themes across the included studies which provide tentative information for what would be needed to make low carbon residential retrofit/renovation policy work. Secondly, we make an overall observation that the included studies did not provide sufficient evidence or establish conclusive results about the effectiveness of specific low carbon policies compared to other policies.

Cost savings from efficiency gains are at the core of the green building business case. Significantly lower energy bills are said to be a major factor in the green rent premium observed in earlier studies. Our study tests this relationship by inferring energy costs from operating expenses for a large dataset of U.S. office buildings and relating them to rental rates. We find that eco-certification is associated with a higher than anticipated total energy expenditure, which is the opposite of its expected effect.

Heat pumps are relatively simple appliances. They share similar components to refrigerators and air conditioners and effectively move an external source of heat to where it is needed, such as in buildings for heating or the production of hot water. Their key value is efficiency; for each unit of electricity consumed to operate them, they produce multiple units of usable heat. Because of this, they require much less energy input for a similar heating outcome compared to combustion technologies, making them naturally cleaner and generally cost effective to run.