In many developing countries, people rely on inefficient stoves fuelled by bio-mass, coal and manure for cooking. The fine particulates (PM2.5) emitted from these stoves not only harm human health, but they also disrupt climate systems. Un-fortunately, economic, technological, social and institutional barriers have often slowed the widespread adoption of cleaner stoves or fuels. Several studies have offered qualitative assessments of these barriers. However, for those assessments to be factored into modelling studies that governments increasingly use to in-form policy, quantitative evaluations of the impacts of different barriers are much needed. This paper uses the case of Thailand to offer a quantitative assessment of how much key barriers affect the diffusion of improved stoves and fuels. It shows that the combined effects of economic, technological, social and institutional bar-riers are significant—slowing diffusion rates by between 60 and 70 per cent. The paper further demonstrates that the social and institutional barriers—which are not typically included in modelling scenarios—are of comparable or greater size than the technological and economic barriers. The study concludes that countries such as Thailand would be well advised to focus more on creating enabling envi-ronments that support institutional coordination across relevant agencies; create consistency in policy objectives; and invest in awareness raising and encourage public comments on alternatives to traditional stoves or dirty fuels.