Significant uncertainties regarding the evaluation of environmental impact from the use ofenergy motivates the need for a unified evaluation approach. In this paper a marginalapproach for general evaluation of CO2 equivalent emissions from the use of district heat inSweden is proposed. A predefined national marginal heat production mix is used to define amarginal heat evaluation approach to calculate the greenhouse gas emissions from the use ofdistrict heating. The novel approach offers a method for justified comparisons of differenttypes of energy use. By using the marginal heat evaluation approach it was shown that theevaluation of the electricity used in heat production for district heating is significant for theCO2 equivalent emissions. A survey of general district heating CO2 emission evaluationexamples is also included in the paper. The marginal heat use approach generates high CO2equivalent emission values in comparison with earlier studies. The overall conclusion of thepaper is that there is a need for further research and discussion regarding development ofmethods for energy use evaluation. The general marginal heat use approach is part of thesolution to this problem.