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Comparison study

“What legislators define as ‘high-efficiency’ HVACD systems, are actually not the most efficient”

"HVACD systems are a high-cost aspect of any cannabis cultivation project and can be extremely costly if used incorrectly. In some states, legislators are defining a 'high efficiency' HVACD system, but those are not the most efficient and do not align with cultivators' needs." Anvil Agrinomincs, Anderson Porter Design, and Zartarian Engineering recently did a joint study, objectively comparing three different climate control systems for a cannabis flowering room. The research aimed to answer practical questions such as efficiency, installation cost, performance, and maintenance cost. 

In the comparison study, two 'VRF-style' HVAC systems (ducted and unducted) are included because some jurisdictions have explicitly called them out in their cannabis legislation as a high-efficiency option. The third option is an integrated HVACD system specifically designed for handling the sensible, latent, and dehumidification loads in the same horticultural application in a 'packaged' arrangement. The three systems were modeled under the same environmental conditions and room arrangements. 

According to the results, the system that uses the most energy is the VRF Split System at 626,836 kWh/year. The Integrated HVACD system uses the least amount of energy, at 14% less than the ductless split system and 16% less than the VRF Split system. 

When it comes to construction costs, the study compared the construction cost per HVACD system for one flower room. The Integrated HVACD system is the most affordable at $177 per square foot. The most expensive system is the VRF Split system at $236 per square foot, which is more than the ductless split system at $194 per square foot. The companies explain that while all systems have very similar costs of equipment, there are some significant contributors to the cost difference. For example, the higher cost for the ductless splits and the VRF is due to the need for dehumidifiers for moisture removal, which is not needed for the packaged purpose-built system.

The packaged purpose-built system also wins when it comes to maintenance and service costs. "They are made to run 24/7, and most have variable capacity compressors allowing them to more closely match the load in the space. These units typically can handle the entire sensible load and moisture removal without the need for additional dehumidifiers. These units will also accept a wide variety of different filter types. With fewer moving parts, this option is the least costly when it comes to maintenance and service cost."

But which one of the three actually performs the best? "The temperature and humidity ranges are much tighter and change more slowly with the purpose-built HVACD system. The stability conferred by an integrated HVAC system leads to greatly improved plant performance, health, yield, and ultimately, facility profitability. Furthermore, with an Integrated HVACD system, there are much fewer pieces of equipment to control and coordinate, leading to much easier control for the operator."

Overall, the comparison study clearly shows that the Integrated HVACD system performs best, costs less, and operates with less energy than the other two systems in the study. "This should result in a faster ROI. Importantly for the states administering and monitoring CEA in their jurisdictions, Integrated HVACD systems will be more energy efficient," the study concludes.

For the complete study, go to 

For more information:
Anderson Porter Design 

Anvil Agrinomincs
LinkedIn: Anvil Agrinomincs, LLC

Zartarian Engineering & Precision AG