Internet of Things (IOT) services provide new security and privacy challenges in our everyday life. But no empirical instrument has been developed for the class of IOT services that identifies privacy factors that predict usage intentions and individuals' willingness to provide personal information. The contribution of this paper is to address this lack of research. The proposed research model integrates the Extended Privacy Calculus Model and the Technology Acceptance Model and is pre-tested with 30 IOT experts. Results indicate that intentions to use IOT services are influenced by various factors such as perceived privacy risks and personal interest. It is further assumed that factors such as legislation, data security or transparency of information use influence the adoption of IOT services. Accordingly, further research must focus on a better understanding of these factors to increase the adoption of both useful and secure IOT services.