This paper looks at the ways in which discomfort from summer overheating can be avoided in European office buildings. Starting with the results from field surveys and applying adaptive comfort theory the paper defines comfortable conditions and the range of acceptable temperature around these, in buildings in both free running mode and those being heated or cooled. Data from the EU project SCATs are used to explore how an upper envelope of acceptable temperatures might be defined. Upper limits for temperatures in buildings with and without heating and cooling are suggested in terms of the running mean of the outdoor temperature. (c) 2006 Elsevier Ltd. All rights reserved.