Climate makes a big difference in the health and productivity of your cannabis plants. The good news is if you’re growing indoors, you get to create that climate! The key to a good grow room climate control is proper ventilation. Keep reading to learn why grow room ventilation is so important, and also to discover the key components of grow room ventilation systems.

Why Ventilation Is Important

Ventilation means “moving air.” In a grow room, you want to move old air out and new air in. There are four core things good ventilation allows for in a grow room.

Humidity Control

As plants photosynthesize, they create water. The water passes out through the leaves in a process called transpiration. This is why grow rooms become so humid if there’s not enough airflow. Proper ventilation circulates the air to keep humidity levels in check. Too much humidity can cause plants to suffocate or rot.

Pest Control

Pests, like spider mites and fungus gnats, thrive in humid zones. A good ventilation system is therefore important for grow room pest control.


Grow room lights are necessary, but they do give off a lot of heat. Ventilation ensures this heat dissipates, ideally keeping your grow room temperature between 75 and 85 degrees F.

Carbon Dioxide Levels

Plants give off oxygen, and they take in carbon dioxide. A good ventilation system makes sure fresh carbon dioxide is always coming in for the plants to use. It also pushes out the oxygen.

Components of Grow Roof Ventilation Systems

Every grow room setup is a bit different. Some grow rooms only need one or two of these ventilation components. Other grow rooms need them all.

Oscillating Fans

These large fans circulate air throughout the space. This helps keep the temperature and humidity even throughout the grow room.

Air Intake

The air intake brings fresh air into the grow room. There are two types of air intakes commercial HVAC mechanical contractors can install. Passive intakes use negative pressure to bring air into the room. Active intakes use a fan to essentially pull air into the grow room.

Exhaust Fan

The exhaust fan exhausts stale air from the grow room. Exhaust fans should be placed on the opposite wall from the air intake so air is continually moving through the space.


In more humid climates or large grow rooms, you may need your commercial HVAC service company to add a dehumidifier to the system. It removes moisture from the air, condensing it into water.

CO2 Injector

If your plants are not getting enough CO2, then you can add a CO2 injector to your ventilation system. It adds extra carbon dioxide to the intake air.Perfect your ventilation system and your plants will thank you with better health. If you’re looking for a commercial HVAC repair and service company, contact H&H Commercial Services, Inc. We offer grow room ventilation services and more.