Which factor has a direct impact on a building's energy performance?

The size and location of fenestration significantly influence a building's energy performance because they are key components in controlling heat gain, heat loss, and daylighting within the indoor environment. Properly sized windows and their strategic placement can optimize natural light while minimizing unwanted solar heat gain during warmer months. Conversely, inadequate or poorly located fenestration can lead to excessive energy consumption for heating and cooling, as well as increased reliance on artificial lighting.

In addition, the selection of window glazing and the insulation properties around fenestration affect how much energy is transferred through the building envelope. For example, double-glazed windows provide better thermal performance than single-glazed ones, impacting the overall energy efficiency of the building. By enhancing the design of fenestration, architects can improve energy performance and contribute to sustainable building practices.

While factors like the number of floors, type of construction materials, and height of the building do influence energy performance in various ways, they do not have as direct an impact on thermal comfort and energy usage as the fenestration elements do.