The goal of this research is the derivation of the theoretical approximation tool for evaluation of efficiency improvement potential applying the proportional pressure control for variable speed pumps in heating systems. The proportional pressure control was compared with the constant differential pressure control. For this reason, energy calculation analyses were realized for centrifugal pumps. The interaction was found between the energy consumption, heating water leakage, and declination of pump proportional pressure control curve at the specific load profile. The results show that the reduction of annual energy consumption can be achieved up to 48% and the reduction of annual heating water leakage – up to 24% of the existing pipe leakage rate, if the proportional pressure control is applied and the declination of pump proportional pressure control curve is up to 90%.