The best time to install a decentralized heat recovery system is during the initial construction or remodel of a building or space. This is because installing the system during the construction or remodel phase allows for the proper ductwork and infrastructure to be installed and integrated into the building, making the installation process more efficient and cost-effective. It also allows for the system to be customized to the specific needs of the building or space.
However, it is also possible to retrofit an existing building or space with a decentralized heat recovery system. This would require a professional assessment of the existing HVAC and ductwork system, and the installation process might be more complex and costly than installing during the initial construction or remodel.
It is also recommended to schedule the installation of a decentralized heat recovery system during the milder seasons, to avoid any possible discomfort to the occupants due to temperature variations while the installation is on progress.