Recent research has indicated a significant potential for providing demand response using Economic Model Predictive Control (E-MPC) of radiators in residential space heating systems. Previous studies indicate the need for distinct temperatures in different rooms, which would require an E-MPC with different temperature constraints across the dwelling. Studies on E-MPC concepts for this purpose often assume that it is possible to measure the heating power delivered to each room separately. However, this assumption is not valid in typical existing residential buildings heated by hydronic radiators; they only have one heat meter measuring the heating use of the entire housing unit. This study presents a simulation-based study of a novel dual-zone E-MPC scheme that relies on indoor air temperature measurements in individual rooms of the housing unit, and only one heat meter measuring the total heating use for space heating and domestic hot water. The results indicate that the proposed scheme has the same load shifting potential as an E-MPC using room-level heat metering. The proposed scheme thus reduces the additional hardware and data infrastructure needed for the practical realization of E-MPC of residential space heating systems for demand response purposes.