I should think there are several approaches to measuring any individual’s carbon footprint e.g. http://carbontrust.co.uk and http://actonco2.direct.gov.uk (and they will probably all produce different results). In my original post I was more concerned with the overheads companies could save rather than the cost of remote working per se. What you are looking for is the differences between travelling to work compared to working from home or a local office. Car travel being the major one. Remote workers still use some energy to heat, light and power equipment but in most cases I suggest they will be heating homes anyway and the power requirements for the computer and lighting are certainly no more in a domestic environment compared to central office.