The promotion of low-carbon home retrofit among UK homeowners is widely recognised as an important strategy to reduce operational energy use in dwellings and mitigate climate change. The related predominant UK policy approach is to address various market failures and develop the market for low-carbon retrofit and innovation. The current low uptake rate of low-carbon home retrofit suggests that a complementary policy approach is necessary to increase it and support households in their change towards low-carbon living. This paper uses an innovation framework to analyse retrofit as an innovation-decision process of several stages. Low-carbon technology is conceptualised at three nested levels: product, design option and technological system. A multiple-case study approach is used to analyse eight home retrofit cases from the SuperHomes network, that achieved significant carbon emission reductions through retrofit activities. Case analysis shows that: (i) homeowners collect information for each technology level through different communication channels, which are not interchangeable; (ii) homeowners develop a certain capacity to transform their environmental concerns into substantial retrofit activities; (iii) the positive retrofit experience of homeowners is crucial to develop such capacity and to convince others to retrofit their homes. These findings have important implications for energy policy on retrofit uptake in UK to support household transition to low-carbon living.