Nowadays, household refrigeration appliances belong to the standard equipment of most homes. Since refrigerators, freezers and refrigerator-freezer combinations generally operate continuously throughout their service life, they range among the largest energy users in the residential sector. As a consequence, policies were established and revised over time to improve refrigeration appliance’s efficiency and decrease their environmental impacts. However, certain characteristics, such as the efficiency loss over time were largely disregarded by previous research and, consequently, its impact on appliance’s energy consumption is yet unknown. Although operational features, i.e. the daily consumer interactions with refrigeration appliances, were monitored in the past their influence was similarly neglected. Therefore, this thesis followed two main objectives in order to close this research gap.