This research integrates both motivational and cognitive approaches to better understand consumers' purchase behaviour of energy efficient household appliances in emerging markets. A unique values, knowledge, attitudes and behaviour model was developed, and then validated by obtaining data from Vietnamese consumers which yielded 682 usable responses. The findings confirm that consumers with stronger adherence to egoistic values are more likely to develop negative attitudes towards environmental protection, and they tend to formulate positive attitudes towards individual inconvenience associated with the purchase of energy efficient appliances. In contrast, biospheric and altruistic values facilitate consumers' purchase behaviour by enhancing their attitudes towards environmental protection, and by also reducing their attitudes in relation to individual inconvenience. Interestingly, consumers with high knowledge about energy efficient appliances tend to believe that the purchase of such products is important for environmental protection, and they are likely to negate the perception of inconvenience associated with the purchase. Attitudes were found to be significant determinants of both purchase intention and behaviour. The implications for policymakers, marketers and other stakeholders are discussed and future research directions presented.