Disclosed is a breathable heater element for a garment or for the lining of a garment such as an outdoor jacket, e.g. a waterproof jacket. The heater element is formed from porous metallised fabric such a nickel plated woven polyester fabric by photochemical etching of a suitable track pattern onto the metallised fabric. The formed heater element is then laminated into a lining. The material of the lining may be impregnated with microencapsulated functional chemicals such as fragrances, perfumes, antimicrobials or insect repellents. The microcapsules release their contents on activation due to heat generated by the heater element.