Panel heating systems are commonplace in new buildings and are increasingly being retrofitted in existing buildings. However, these systems can lead to a high level of radiation asymmetry, especially in insufficiently insulated old buildings. The influence of this radiation asymmetry on thermal comfort has not yet been extensively researched and can only be poorly described using the normative models for assessing thermal comfort. In the first step of a large series of tests described here, possible approaches for evaluating thermal comfort are presented. In order to assess the suitability of these evaluation approaches, initial experimental measurements and simulations were carried out with small heating panels. The results illustrate large deviations of the different comfort models and show that both a local and a global approach are useful when considering the influence of radiation asymmetry on thermal comfort.