Which process is essential for improving the energy efficiency of older buildings?

Retrofitting is the process specifically focused on enhancing the energy efficiency of existing buildings, particularly older ones. This involves upgrading systems such as heating, ventilation, air conditioning (HVAC), insulation, windows, and lighting to more energy-efficient models and technologies. The goal is to reduce energy consumption, improve comfort, and often lower operational costs without the need for tearing down the existing structure.

Reconstruction and demolition imply significant alterations or removing structures entirely, which do not directly address improving energy efficiency in a cost-effective manner. While renovation can include energy-efficient upgrades, it is a broader term that encompasses various modifications and might not always focus specifically on energy improvements. Retrofitting, however, is the targeted approach specifically for improving the energy performance of existing buildings, making it the most relevant choice in this context.