The challenge of achieving low-carbon communities cannot be underestimated. While government policies set ambitious targets for carbon-reduction over the next 40 years, there remains an urgent need for tools and initiatives to deliver these reductions through behaviour-change among individuals, households and communities. This chapter sets out a 'New Economics' agenda for sustainable consumption which addresses the need for low-carbon communities. It then applies these criteria in a critical examination of complementary currencies in the UK (time banking and local money). These are alternative mechanisms for exchanging goods and services within a community, which do not use money, and which aim instead to build local economic resilience and social capital. The potential of these initiatives as carbon-reduction tools has not previously been considered. Time banking appears to offer the greatest potential for carbon-reduction through offering a supportive social network which meets some of the participants' social and psychological needs for recognition, esteem and belongingness - needs which might otherwise be met through material consumption. In contrast, local money systems aim to strengthen and build resilience in local economies, and their principal impact on consumption is through localisation and import-substitution - which brings carbon-reductions from avoiding transport costs. What the two initiatives share is a commitment to building new systems of exchange which meet sustainability criteria, and express a wider set of values than mainstream money. The research and policy implications of these findings are discussed.