Abstract Estimating heat emission losses of heating systems is an important task of energy efficiency assessments in buildings. However, the present international standards do not specify how emission losses should be calculated or measured for different emitter and control system configurations. Aiming to fill this gap, here we propose a method for computing the temperature setpoint variations by addressing the heat distribution throughout a room with space heat emitters. This general and exact procedure enables the calculation of product category-specific setpoint variations for different types of heat emitters, accounting for the overall heat balance in the enclosure and including the cross-correlations of each component. Our method complements the procedure presented in the Standard EN15316-2, making it possible to compute emission losses as product-specific values of setpoint variations instead of tabulated values. As the main finding of the study, the calculation process is defined for a European Reference Room that allows an accurate and transparent evaluation of total setpoint variations. These are computed for specific products from measured vertical stratification and control parameters, by means of an annual IDA ICE simulation model of the reference enclosure. Applying the method to an annual energy performance simulation for an old and a new building in Strasbourg shows that emission losses are compensated by a total setpoint variation of respectively up to 2.00 °C and 1.20 °C, corresponding to an increase in total heating energy usage of up to 22% and 20%.