In this paper, dynamic simulation was used to compare the energy performance of three innovative HVACsystems: (A) mechanical ventilation with heat recovery (MVHR) and micro heat pump, (B) exhaust ventilation with exhaust air-to-water heat pump and ventilation radiators, and (C) exhaust ventilation with air-to-water heat pump and ventilation radiators, to a reference system: (D) exhaust ventilation with air-to-water heat pump and panel radiators. System A was modelled in MATLAB Simulink and systems B and C in TRNSYS 17. The reference system was modelled in both tools, for comparison between the two. All systems were tested with a model of a renovated single family house for varying U-values, climates, infiltration and ventilation rates. It was found that A was the best system for lower heating demand, while for higher heating demand system B would be preferable. System C was better than the reference system, but not as good as A or B. The difference in energy consumption of the reference system was less than 2 kWh/(m(2) a) between Simulink and TRNSYS. This could be explained by the different ways of handling solar gains, but also by the fact that the TRNSYS systems supplied slightly more than the ideal heating demand. (C) 2014 Elsevier B.V. All rights reserved.