This paper attempts to demonstrate how the internal heat gains influence the energy performance of industrial buildings. In order to achieve this, the paper considers a concrete case of a production hall. The energy performance of this buiding is calculated by taken into account three variants: the first one – a reference variant, the second one- a version that does not account for heat gains related to the production process and the third one - normal operating conditions. The calculation methodology is the one related to Romanian regulations in force, using the simplifying assumptions of these regulations.
