The role of income in energy consumption behaviour: Evidence from French households data Jean-Michel Cayla a,b,n , Nadia Maizi a , Christophe Marchand b a Mines ParisTech Centre de Mathe ´matiques Applique´es (CMA, Centre of Applied Mathematics), Sophia-Antipolis, France b Electricite´ de France (EDF R&D), Renardi  eres Site, Morˆ et sur Loing, France article info Article history: Received 17 August 2010 Accepted 20 September 2011 Keywords: Household energy consumption Investment choice Energy behaviour abstract The main purpose of this paper is to characterise quantitatively the impact of income on household energy consumption in the residential and transport sectors. Starting from the data collected in a paper survey, we analyse the extent of the constraint experienced by households in terms of equipment purchasing behaviour and daily energy consumption. This analysis shows that the least well-off households are particularly constrained since the share of their budget represented by these energy services is very large (15–25%), and this corresponds to a level of energy service well below that of the better-off households. The case of space-heating shows a factor of 2 in terms of level of comfort achieved between the extreme 10-percentiles. These households also face a strong capital constraint for equipment purchases. This leads either to a large increase in the required rate of return or to a reduction in the proportion of households that are prepared to replace their equipment earlier. The least well-off households are thus doubly constrained, since it is more difficult for them to invest. In our opinion, it is crucial to take into account this observation in the context of political measures aimed at reducing households’CO 2 emissions. & 2011 Elsevier Ltd. All rights reserved. 1. Introduction Households do not consume energy for itself but energy services, either at home or for travelling. This consumption of services is embedded in an extremely complex system involving elements of technical, economic, social and psycho-social origin. In the case of the residential sector, it has been shown that the level of energy consumption in a single dwelling may vary largely accord- ing to the household behaviour (Moussaoui, 2006). A previous study that we conducted on space heating energy consumption in France emphasises the significant impact of behaviour. Indeed, it seems that about 33% of consumption variations can be attributed to household characteristics (Cayla et al., 2010) which is fairly coherent with Sonderegger’s results (1977). Understanding the determinants that govern energy consumption behaviour has thus been the subject of abundant literature for more than 30 years. Amongst all these household variables, it is household income that seems to play the greatest role in energy consumption (Dillman et al., 1983; Black et al., 1985). From an economic point of view, on the one hand, income exerts a large influence on the implicit discount rate used by the household when purchasing equipment, as shown by Hausman’s pioneering work (1979) on air cooler devices or by Goett and McFadden (1982) on space heating systems. On the other hand, it also influences the level of energy consumption via the income elasticity parameter: the higher the income, the higher the energy consumption. In fact, income also plays a role in the type of reduction strategy likely to be adopted by households. Better-off households tend to invest in efficient equip- ment, whereas the least well-off households tend to curtail their daily energy consumption (Verhallen and Van Raaij, 1981; Black et al., 1985; Bartiaux et al., 2006). From a sociological point of view, a combination of socio-demographic attributes, such as age, type of family, urban/rural area or income constitute households’ social classes. These social classes define the ways people live, which in turn result in practices that affect energy consumption. However, amongst these variables, the most important is once again income, or rather the income class, as it remains the major constituent element of social class (Bigot, 2007). The main purpose of this paper is thus to attempt to char- acterise quantitatively the impact of income on household energy consumption in the residential and transport fields. In particular, we seek to show the constraint that income places on households relating to both purchasing efficient equipments and daily energy consumption. Section 2 presents the methodology and content of the survey that supports the analyses in this paper. Section 3 looks at the impact of income on daily energy consumption and its impact on the level of comfort. Section 4 deals with the impact Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/enpol Energy Policy 0301-4215/$ - see front matter & 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.enpol.2011.09.036 n Corresponding author at: Mines ParisTech Centre de Mathe ´ matiques Applique ´es (CMA, Centre of Applied Mathematics), Sophia-Antipolis, France. Tel.: þ33 686455427. E-mail address: jeanmichel.cayla@gmail.com (J.-M. Cayla). Please cite this article as: Cayla, J.-M., et al., The role of income in energy consumption behaviour: Evidence from French households data. Energy Policy (2011), doi:10.1016/j.enpol.2011.09.036 Energy Policy ] (]]]]) ]]]–]]]