Energy-efficient biomass cookstoves and small solar systems play an important role in the transition to clean energy. Despite their affordability and scalability, uptake remains low among households in sub-Saharan Africa. This paper examines whether household-level behavioural factors help explain this under-adoption. Drawing on data from real-purchase offers in rural Rwanda and Senegal, we analyse how willingness to pay for the technologies varies with risk aversion, innovation resistance, time preferences and beliefs. These traits explain part of the variation in purchase decisions, though effects are generally moderate. The findings improve our understanding of consumer behaviour with regard to innovative consumer goods at the base of the pyramid and inform policy and market strategies of suppliers entering these markets. We conclude by recommending that behavioural approaches be applied conservatively and only in conjunction with efforts to improve affordability and access.