This paper presents the energy performance evaluation of a marketable net-zero-energy house (NZEH): Solark I at Solar Decathlon China 2013. The assessment methodologies are based on EnergyPlus simulations and measured data. The paper also discusses the reasons for the differences between the results of the simulations and the measurements, analyzes the investment cost, summarizes the lessons learned from the competition, and presents the potential for replicability and transposition from Solark I to implementation in a practical NZEH. The conclusions are that Solark I's investment cost is reasonable, its systems for building-integrated photovoltaics, hot water and heating, and ventilation and air conditioning demonstrated excellent performance based on the results of the energy performance evaluations using EnergyPlus simulations and measured data. Thus, Solark I is a marketable NZEH. (C) 2015 Elsevier Ltd. All rights reserved.