In horticulture, a closed-loop system refers to a climate-controlled room where plants are conditioned without the use of outside air. The room's air is first cleaned, dehumidified, and brought to the desired temperature before being recirculated back into the grow room.

This method allows the artificial increase or maintenance of CO₂ levels in the room, which can have a significant impact on yield. 

To increase a plant's CO₂ absorption, it must transpire more through higher energy input, such as light and ambient temperature. Therefore, rooms enriched with CO₂ are operated at higher temperatures than those without it.

The AIRBEND split units are designed specifically for this task and are easy to install, allowing for quick operation. These air conditioning units come in two output classes: 14 kW and 28 kW.