EXT’air is a greenhouse dehumidification system that uses outside air combined with heat recovery via a dual-flow heat exchanger.

Greenhouses are traditionally dehumidified by heating and ventilation: warm, humid air is expelled through roof vents and replaced by cooler, drier outside air. This method is highly energy-consuming and, from a climate-management perspective, imprecise. It can create cold draughts over crops, reduce climate uniformity and encourage the entry of insects.

EXT’air was developed to achieve major heating-energy savings while improving the greenhouse climate.
How it works: EXT’air is equipped with two variable-speed fans, allowing it to draw in warm, humid greenhouse air on one side and colder, drier outdoor air on the other. Inside the unit, two separate air circuits allow the airstreams to exchange energy through a dual-flow heat exchanger. There is no mixing: the dry outside air is warmed to a temperature very close to that of the greenhouse before being blown back inside.

For example, with a greenhouse climate at 20°C / 80% RH and outdoor conditions at 0°C / 80% RH, the air supplied back into the greenhouse will be at 18°C / 23% RH.

Nearly 90% of the heat is saved, since the heat from the extracted greenhouse air is recovered, and dehumidification no longer requires opening the vents. Thermal screens can remain closed without risking excessive humidity.

With EXT’air: keep the heat, not the humidity!