In this paper, we investigate the energy usage and emission efficiency of radiator and underfloor heating systems coupled with ON/OFF and PI controls, by performing annual simulations with the IDA ICE software package. Results from measurements carried out in early 2018 at the nZEB test facility near the Tallinn University of Technology are used to calibrate validated emitter and controller models. The calibrated models are then used to assess the energy performance of the systems in a simulation spanning the whole year, using climate data for Strasbourg in the European reference room. The annual simulation is conducted in a specific room with fixed geometry and boundary conditions. As a novelty value of the present study, we impose a non-standard control strategy based on maintaining a specified operative temperature within the room. A single-valued performance indicator, in the form of an increased air temperature set-point, is accordingly obtained for each emitter configuration to be used in further calculations of hourly, monthly or annual heating energy usage. Such a temperature increment accounts for imperfect control, air stratification within the room and the additional temperature increase that is required for achieving a desired operative temperature.