Investigating the potential of overheating in UK dwellings as a consequence of extant climate change A.D. Peacock n , D.P. Jenkins, D. Kane Urban Energy Group, School of the Built Environment, Heriot Watt University, Riccarton, Edinburgh, EH14 4AS article info Article history: Received 25 November 2008 Accepted 12 January 2010 Available online 10 April 2010 Keywords: Domestic Overheating Climate change Thermal mass Simulation abstract Dynamic simulation is used with defined domestic building variants to investigate internal temperatures of UK dwellings. Factors such as a warming climate and varying internal heat gains are estimated to examine whether UK domestic buildings are likely to be prone to overheating in the future, and therefore require mechanical air conditioning. The study suggests that the ability, or inability, of the occupant to adapt to bedroom temperature is paramount in the understanding of the conditions for overheating. While this is difficult to quantify (and a range of comfort temperatures are proposed), the effect of changing the building construction and geographical location can result in significantly different thermal conditions. As might be expected, the problem appears most noticeable for buildings in the south of the UK and with lightweight constructions. Even with a window-opening schedule applied to such a scenario, the average internal temperature is simulated as being over 28 1C for almost 12% of the year. A different metric, defined as ‘‘cooling nights’’, suggests that there might be a cooling problem in bedroom areas for approximately a third of the year. In the North of the UK, and also for solid wall dwellings, this problem diminishes significantly. & 2010 Elsevier Ltd. All rights reserved. 1. Introduction The UK Government has recently placed on a legislative footing the pledge to reduce CO 2 emissions by 80% by 2050 (DEFRA, 2008a). The extent to which these savings will be achieved will to some extent be predicated on the response of the domestic sector which currently is responsible for approxi- mately 27% of all UK CO 2 emissions (Shorrock et al., 2003). In addition, in successive IPCC Working Group reports (Levine et al., 2007) and UK Government Energy White Paper (DTI, 2006), it has been concluded that substantial reductions in CO 2 emissions from energy use in domestic buildings can be achieved using energy efficiency technologies that already exist widely and have been successfully deployed. A series of projects have indicated the technologies that could be deployed in the existing stock to achieve these cuts (Peacock et al., 2007; WWF-UK, 2008; Bell and Lowe, 2000). In the main, these do not include an assessment of how energy consumption (and commensurate CO 2 emissions) might grow in the domestic sector in future decades. Two factors that may cause CO 2 emissions to rise in the future are; (a) increased electricity consumption—for instance electricity consumption rose by an average of 1.3% per annum between 1990 and 2005 with this trend projected to continue or increase due to the growth of the consumer electronics and home entertainment market (BERR, 2008; EST, 2006) and (b) a warming UK climate (Jenkins et al., 2007). These two factors have a somewhat symbiotic relationship as the former leads to increased internal gains in housing, the latter to increased external gains and the combination of the two may herald a cooling season in the UK domestic sector. A cooling season may be viewed as a period of time where mechanical cooling is required to maintain some pre-defined thermal comfort condition. This will be a largely novel energy demand in the UK that will potentially have a detrimental effect on the ability of the domestic sector to contribute to the aforementioned targets. This investigation considers how the advent of a cooling season might be judged in the UK. Using this judgement it then explores, using a modelling approach, how three domestic building variants of differing constructions respond to both a possible change in electrical consumption and the forecasted, near term warming of the UK climate. This UK climate was represented using UK Climate Impacts Programme 2002 (UKCIP02) algorithms (Belcher et al., 2005) for 2010–2040 to morph CIBSE Test Reference Year (TRY) 2005 climates (CIBSE, 2005) using a medium high emissions scenario. 2. Domestic cooling requirement It is thought that early market growth in domestic air conditioning systems may be driven by distress purchasing ARTICLE IN PRESS Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/enpol Energy Policy 0301-4215/$ - see front matter & 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.enpol.2010.01.021 n Corresponding author. Tel.: + 44 131 451 4637; fax: + 44 131 451 3132. E-mail address: a.d.peacock@hw.ac.uk (A.D. Peacock). Energy Policy 38 (2010) 3277–3288