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Category: Project

Description: Lab experiments and modelling have confirmed that lowering a boiler’s flow temperature (the temperature to which the boiler heats water that flows through a home’s radiators) results in a reduction of total household gas use. This is important both for reducing household energy costs and emissions. However, this research found that the gas savings weren’t just a result of an increase in boiler efficiency (the expected mechanism), but also from cooler room temperatures. The possibility that rooms may be cooler than before may mean the savings found in lab experiments and modelling may not occur to the same extent in the field; as households may notice the difference in temperature and take compensatory behaviours that could reduce, remove, or even reverse the gas savings. It is therefore necessary to test this intervention in the real world to better understand whether households notice a change in room temperature or comfort, and if they accept the change or try to take suboptimal compensatory behaviours that remove the gas saving. Another key purpose of this research is to better understand how giving flow temperature guidance tailored to the time of year impacts gas savings and thermal comfort, particularly in the spring and autumn. The majority of advice on this measure currently gives a generic recommendation to lower flow temperatures to 60°C. However, in warmer months further savings could be made if households were encouraged to lower their flow temperature to 55°C or lower. However, the same questions relating to household comfort, behaviour in response to changes in comfort, and gas use discussed above still arise and need to be investigated. To understand these questions Nesta will run a randomised controlled trial to investigate the impact of giving boiler flow temperature advice on household gas use and self-reported thermal comfort. In developing a better understanding of the impacts of flow temperature advice on household gas use and thermal comfort, recommendations that are currently given on this measure could be improved. For example, extra guidance could be given alongside the advice, or different flow temperature recommendations could be given at different times of year.