To Ventilate, or Not?

Whatever the size and layout of your grow room may be, there are some things that are necessary for every grow room to ensure a healthy and successful indoor harvest with the maximum possible yields. These must-have elements that are needed in every cannabis grow room include a specialized HVAC system, a sufficient lighting system, dehumidification, automated controls, and last but not the least, a functioning ventilation system.

Whether required by your local building code or to simply add another tool to your proverbial climate control toolbox, a ventilation system should be considered when planning HVAC for your cultivation facility.

With that information in mind, let us discuss why ventilation is such an important element of the growth and cultivation of cannabis in grow room as we introduce the two primary methods: ventilation and HVAC integration.

Importance of Ventilation When Growing Cannabis
Ventilation is needed for all grow room HVAC-D systems because of the utility they bring to the grow room and for life safety building code reasons.

Every living thing in this world requires an air of sufficient quality for survival, and this applies to plants as well. In order for cannabis plants to thrive and grow to the best of their ability, they need air with a proper amount of carbon dioxide, and the air must also be free from any sort of pollution.

Air quality that fulfills these conditions may be difficult to provide to the plants using a traditional HVAC system, which is why dedicated ventilation systems might be beneficial to influence healthy cannabis plant growth.

Furthermore, another reason a ventilation system is such a great addition to any grow room HVAC design is because of its heat removal capabilities. Cannabis plants require a balanced environment in order to optimize yields, and that means that it must not be too cold, but it must not be too hot as well. Setting up a system that can do both is critical.

CFM and CMM: What Are They?
When researching the market for a suitable ventilation system, terms like fan CFM and CMM are thrown around to describe certain pieces of equipment for the grow room, so what do they mean? CFM and CMM are actually terms that are short for Cubic Feet per Minute or Cubic Meters per Minute, respectively, and these units are used to describe the rate at which air is exchanged in a grow room. This is important because a normal rate of air exchange in the grow room helps with the regulation of the temperature, which ensures efficient heat exchange in the environment as well.

Due to the closed-up nature of a grow room, the entire room requires the complete air volume to be circulated throughout the enclosure, and this rate of air exchange is the minimum requirement needed to maintain a suitable grow environment.

HVAC Integrated System
Traditionally an integrated system uses an economizer to increase efficiency when outside weather allows. Mixing the fresh and conditioned air increases the efficiency of the system. This is due to less run time on your cooling system to meet desired indoor temperatures. This is particularly effective for schools, offices, and human-occupied areas due to the inherent need for fresh air.

In a grow space, this method is implemented in an engineered way to safely bring in the fresh air as needed. Electrically controlled dampers bring in fresh, filtered air to clear the room in a CO2 emergency or to bring in cold air to lower electric bills.

Proper filtration on the way in is required to minimize the threats of bacteria, mold, and pollen. Carbon filters are used on the exhaust to prevent the smell from spreading outside the building. The downside to this type of system is the requirement for ducting from outside and throughout the grow space. Further, the controls behind such a system might not be best suited a cannabis grow operation.

Ducting can increase the cost of installation as well as increase the amount of cleaning needed in a room between harvests. Further, these systems are typically sized at a fraction of a standalone ventilation system, leaving airflow to be desired.

Ventilation as a Tool
Standalone ventilation uses an electronically controlled filtered air intake and an exhaust fan(s) strategically placed in a room to provide ventilation. This system runs independently of the HVAC. This approach is designed specifically with a grow space in mind; to stop outside airflow unless required by the room conditions. The air intake is fitted with an integrated filter rack. A MERV 15 filter is rated to stop pollen, mold, dust, bacteria, pollen, and insecticides.

When fresh air is brought in to use outside air to supplement cooling or when CO2 necessitates it, the filter will keep anything that should stay outside. The exhaust fan is fitted with a carbon filter to meet city and county regulations on odor control. The entire system is custom designed to bring in the right amount of airflow based on the size of the space. The system can be set to activate slightly above or below the set point of the main HVAC, depending on
the ambient temperature.

Conclusion
Ventilation can help increase the efficiency and effectiveness of a grow room environment as well as provide a safety system for CO2. Carbon dioxide is one of the main requirements which every plant needs in order to grow healthy, and
this is what ventilation systems and pieces of equipment such as the inline fan provide for the grow room.

Many growers will prefer to run a sealed growing environment, which is a solid primary method of environmental management. However, having system-level redundancy with backup ventilation has provided more tools for effective grow room HVAC, while satisfying building code requirements.