Phase change materials (PCM) are known as an effective technology to store larger amounts of thermal energy per unit mass than conventional thermal mass building materials such as concrete and stone. They add thermal stability to lightweight constructions without adding physical mass. This paper presents a method to assess the effect of PCMs on thermal comfort and energy consumption in UK dwellings in summer months. A methodology is presented to assess the impact of climate change temperature increases in the UK by considering current, 2020, 2050 and 2080 weather scenarios using the dynamic thermal simulation software DesignBuilder, which employs EnergyPlus as its calculation engine. The study used simulations of a high performance detached house model with a near Passivhaus standard in London, where the impact of climate change effect is predicted to be significant. It was shown that appropriate levels of PCM, with a suitable incorporation mechanism in to the building construction, has significant advantages for residential buildings in terms of reducing total discomfort hours and cooling energy loads. (C) 2015 Elsevier B.V. All rights reserved.