Facilities that have the option to put weight on the roof have a few more choices for the equipment. The roof-mounted equipment will require ductwork to run within the space and provide heat and dehumidification. Each system could be equipped with reheat coils and low ambient controls to allow units to operate even in the winter. The systems provide some efficiency but are mainly used for commercial comfort cooling and heating. Manufacturers are trying to provide more controls and ways to have great rooftop-mounted cannabis systems, but the more precise temperature and humidity requirement needed, the more the units will cost upfront.
Variable Refrigerant Flow systems are just like Split systems but are much larger and can provide more heating and cooling at high efficiency. These systems could be ducted or wall-mounted. They can provide up to 30 tons of cooling on one unit to provide comfort cooling. These systems do not offer the on-demand dehumidification that is really needed in cannabis growth, but they could be a good starting point since they have variable control of cooling that helps regulate dehumidification better than traditional rooftop units that blow air around in the duct. This system could have multiple indoor heads in different zones and provide heating or cooling at the same time. The outdoor equipment would be a condenser that is not much louder than a traditional residential unit.