Abstract: A heating system is provided for an inhaler device, such as an e-cigarette or a personal vaporizer device, for generating an aerosol or a vapour from a liquid to be heated. The system comprises: at least one supply channel for conveying a liquid to be heated from a supply reservoir under capillary action or surface tension forces within the at least one channel; and heating means arranged at an outlet of the at least one supply channel and configured to heat the substance as it emerges from the outlet of the at least one channel. The heating means preferably comprises at least one heating element which extends across a width or an outlet opening of the supply channel and is typically confined to the outlet of the supply channel.