The WFP was initiated to combat fuel poverty and the related excess winter mortality and morbidity among older households in the UK. This winter morbidity is associated with cold indoor climates generally believed to be caused by insufficient heating of the home. The WFP provides households that include a member over the age of 60 years (in the qualifying week of a given year) with a lump sum annual payment in November, with the goal that it will be put towards increased energy use and lead to warmer indoor temperatures. Recent research (Beatty et al., 2011) suggests that recipients spend 41% of the transfer on fuel, much higher than the 3% expected increase if the payment were treated as cash. Although the WFP has the objective of enhancing the health and well-being of the fuel poor, research has not yet evaluated this possibility. The proposed programme of work will treat the WFP as a natural experiment and employ a regression discontinuity design to estimate the potential causal effect of the WFP on household temperature, circulatory (e.g. blood pressure, coronary symptoms) and respiratory (e.g. lung function) health and the presence of infection (e.g. raised C-reactive protein levels.). We also capitalize on the sharp eligibility criteria for the WFP to test whether the payment improves perceptions of physical health and mental health and well-being ratings. The proposed programme of research brings together an interdisciplinary team working in areas of behavioural economics, environmental economics, epidemiology and behavioural medicine who together will build an evidence base for assessing the potential health benefits of the WFP and whether these are located principally amongst those on low incomes.