Although technology readiness (TR) has been found to influence the acceptance and use of information systems (IS), little is known about how TR varies in terms of different demographic variables and how these demographic variables moderate the effects of TR on IS acceptance and use. In this study, we aim to address this gap in prior research by examining the potential age differences in the four technology readiness index (TRI) constructs as well as their effects on IS use intention and its two main antecedents hypothesised in the technology acceptance model (TAM): perceived usefulness and perceived ease of use. The examination is conducted in the context of online electricity services and based on 1,176 online survey responses collected from Finnish consumers and analysed through structural equation modelling (SEM). The findings of the study suggest age differences in the optimism, innovation, and discomfort constructs of TRI, but not in the effects of any of the TRI constructs on the TAM constructs. These findings and their implications are discussed in more detail especially from the perspective of the so-called “young elderly” segment consisting of individuals aged 60–75 years.