Heat recovery systems are highly preferred in today’s world for mitigating the heating and cooling demands of buildings. The main goal of any heat recovery technology utilised in the building sector can be assertd to reduce energy consumption due to heating, ventilation and air-conditioning (HVAC) systems. Several theoretical and simulation works have been done to date in literature. However, works dealing with performance assessment in real operating conditions are very limited. Therefore in this study, a comprehensive thermal comfort analysis of a test house integrated with a novel polycarbonate heat exchanger was carried out. Pre- and post-retrofit, temperature, relative humidity and CO2 measurements were conducted during a week in winter. The results from the pre-retrofit case clearly revealed that the internal CO2 concentration did not cover a desirable range due to a lack of ventilation in the test house. However, following the integration of the novel ventilation system, CO2 concentrations were found to vary notably from 350 to 400 ppm which was satisfactory and corresponded to the actual comfort conditions for indoor environments. Another achievement was that the average relative humidity in the post-retrofit case was found to be 57%, which was good as it was notably higher at the pre-retrofit stage.