This paper presents the results for the operating energy performance of the smart operation for a low carbon energy region (SOLCER) house. The house design is based on a ‘systems’ approach, which integrates the building technologies for electrical and thermal energy systems, together with the architectural design. It is based on the concept of ‘energy positive’ buildings, utilising renewable energy systems which form part of the building envelope construction. The paper describes how the building energy model HTB2, with a range of additional ‘plugins’, has been used to simulate specific elements of the design and the overall energy performance of the house. Measurement data have been used in combination with the energy simulation results to evaluate the performance of the building together with its systems, and identifying the energy performance of individual components of the building. The study has indicated that an energy-positive performance can be achieved through an integrative systems approach. The analysis has indicated that the house, under normal occupancy, needs to import about 26% of its energy from the grid, but over the year its potential export to import ratio can reach 1.3:1. The paper discusses the performance gap between design and operation. It also considers the contribution of a transpired solar air collector (TSC) to space heating. The results have been used to gain a detailed understanding of energy-positive performance.