This paper presents a method for the estimation of potential impact of climate change on the heating energy use of existing houses. The proposed method is based on the house energy signature that is developed from historical energy use data. The method can be applied to any individual house, by using the utility bills from the owner, or can be used by utility companies, which have databases of recorded energy; use for large number of houses. The second case can lead to accurate estimates of potential impact of climate change within a city, a province or a country. A case study of a house in Montreal (Canada) is presented, and the results obtained with different sampling rates of data are discussed. The method is also applied to a sample of I I existing houses, and the results show the reduction of heating energy use between 7.9% and 16.9% due to climate change between the present period (1961-1990) and the future period (2040-2069). (C) 2007 Elsevier Ltd. All rights reserved.