IT artefacts are steadily permeating everyday life, promising to play an increasing role in the management of the domestic environment, just as they have colonised the business domain. The cognitive design of such information systems requires careful attention if their full potential is to be realised and the problems besetting their use in other domains abated. The present study focuses on the design of domestic heating management systems, specifically on the feedback support required to achieve energy savings and therefore contribute to the wider ecological agenda. A PC-based “microworld” simulation called CHESS was developed to model the critical features of a generic central heating system. After receiving training on the simulation task, 45 participants worked on a series of operational scenarios under different levels of system feedback. As hypothesised, the results showed that well-designed feedback resulted in enhanced learning and environmentally-friendly performance. Results are interpreted in terms of goal setting theory: the enhanced feedback provided both an implicit performance goal as well as information directly relating to energy efficiency. It is concluded that designers need to pay careful attention to goal setting mechanisms as well as providing appropriate feedback channels in designing for the home. This is especially important given the distinctive circumstances of the domestic as compared to the business environment, e.g. limited training and support, self-set goals etc. It is also concluded that the microworld approach has a useful heuristic role in IS research both as a theoretical test-bed and source of practical design knowledge.