This paper reports on a project to construct and test an instrument that, for the first time, enables the accurate measurement of convective heat transfer coefficients (chtcs) in real buildings. Computer simulation models for the prediction of heat and airflow in buildings commonly rely on such empirically derived values. However, there are large uncertainties associated with their evaluation and use. The instrument described in this paper has been tested by measuring the chtcs on a heated plate mounted in a test room. The experimental work reported here was made up of two parts: (1) A 'proof of concept' with both platinum resistance (PRT) and thermocouple temperature sensors mounted on a moveable 'tracker'. (2) Measurements made on a reference surface with a final 'fixed' instrument. The results are encouraging. Comparisons of the chtcs determined by the new instrument and the chtcs determined by the 'traditional' heated plate method have shown close agreement. It seems that the new instrument has great potential for use in real buildings. (C) 2004 Elsevier B.V. All rights reserved.