Although students are expected to finish school having a solid understanding of scientific concepts, they graduate from universities maintaining their former misconceptions in several fields, like physics. This study aims at validating the Thermal Concept Evaluation (TCE) test for university student's misconceptions of thermal concepts in everyday contexts. The test was administered to 643 first-year students from six different tertiary education departments in Greece. Item Response Theory (IRT) was used in order to validate and adjust the instrument to the Greek population of students and estimate the discriminating power of items. This assessment found that the majority of students held alternative conceptions about thermal concepts. Socio-demographic and academic variables have impact on students' performance.