The goal of this research is the derivation of method for evaluation of efficiency im-provement potential for district heating systems with focus on variable speed centrifugal pump. The effectiveness of the usage of the proportional pressure control is compared with the constant pressure control. This is why, energy calculation analyses have been realized for variable speed centrifugal pumps, and the theoretical tool of estimation of the effectiveness improvement potential has been derived using the correlation research method. The conclusions are: the 11.2 GWh in total or 58.3% of the annually consumed electrical energy by variable speed centrifugal pumps can be saved up in low scale district heating systems in Latvia, if proportional pressure control is used with the deviation of 80%.