Paper ID: ID079 First Name: Barbara Last Name: Pause Organization: Textile Testing & Innovation, LLc. E-mail: email@example.com Keywords (up to six): phase change material, textile composite, energy efficiency, thermal comfort Abstract (500 words or less) Title: Taking the heat! Introduction of new energy efficient building materials based on the application of phase change material (PCM) The thermal performance of building materials and, hence, buildings can be significantly improved by the application of phase change material (PCM). PCM is a highly-productive thermal storage medium. Applied to a building’s envelope the PCM controls the heat flux into and out of the building. Preliminary investigations have shown that the roof of the structure provides the most efficient location for the PCM. In order to integrate the PCM in a roof structure non-woven composite materials have been developed. The non-woven composite materials consist of a polymer matrix with PCM attached to a non-woven carrier material. The newly-developed non-woven composite materials shall replace the underlay or the moisture barrier currently used in roof structures. Tests, carried out in a model building and computer simulations have shown that the temperature in a living space underneath the roof is reduced significantly on hot summer days by the PCM application in the roof. Furthermore, a substantial decrease in the annual heating demand of a building is obtained by the PCM application.