With so many dehumidification and HVAC offerings on the market for cannabis cultivators, it may be difficult for growers to select the system that is right for their specific situation.
For Geoff Brown, VP of Technical Solutions for Quest, learning as much as possible about what happens in a client’s grow room and how the cultivator expects to operate that room is critical when guiding growers in equipment selection.
Quest’s IQ Series of dehumidifiers, for example, each represent a different offering to the market that is largely based on what a specific cultivator or facility requires.
“In order to determine that accurately, we really need to become partners with the growers,” Brown says. “[We must] learn everything they’re going to do with that system, how they’re going to do it [and] how they anticipate operating their facility.”
In order to determine what equipment might be best, Brown encourages growers to consider these factors:
1. Size of the Operation
The size of a cultivation operation is a key factor when choosing a dehumidification and HVAC system, Brown says. The Quest Evolution, for example, is an indoor split unit, with an air handling piece located inside the facility and a Dry Cooler placed outside as heat protection.
“It’s kind of like the air conditioner that would be on your house, where you have your furnace or your air handler inside and then you’ve got a condensing unit outside,” Brown says.
The Dry Cooler operates on a food-grade water-glycol mix, which is available on all of Quest’s IQ systems that offer cooling. This eliminates the need for refrigerant lines, so if there’s ever a leak in the system, it will leak the food-grade glycol or water onto the facility’s roof or inside the grow room, rather than refrigerant, which could harm the infrastructure or the plants.
These types of systems can operate in any environmental condition, Brown adds, with the capacity to manage a 300- to 2,500-square-foot grow room.
2. Lighting
According to Brown, lighting should be a key consideration when determining HVAC and dehumidification needs in a cultivation space.
“The primary driver of system demand is lighting—what kind of lighting, what intensity of lighting and how many [lights there are],” he says.
Lighting represents the energy that goes into the system, he says, and the lights produce heat that needs to be removed through air conditioning. Although, he adds, some of the light also gets converted by the plants to drive transpiration processes, which creates the need for some level of dehumidification.
3. Irrigation
A grower’s plan for watering their plants is another critical piece of the dehumidification puzzle, Brown says. Hydroponic and open-tray systems create different dehumidification needs, for example, by creating different levels of evaporation in the room.
4. New Build vs. Retrofit
New facility buildouts often fare better with an all-in-one dehumidification and HVAC solution, Brown says, while split systems are often the better fit for retrofitted facilities.
“In general, new-build facilities are typically better off with the all-in-one solution if for no other reason than simplicity,” he says. “You’re only running controls through [one] or maybe two units in a space instead of potentially dozens, so the control side is much easier.”
In addition, the installation cost on the all-in-one solutions is often lower, as electric and plumbing is only required for one or two units instead of several.
“Then, on the maintenance side, you’ve got one or two units maintained, not dozens,” Brown says. “The maintenance items in a grow room—even just things like replacing filters—can be quite a lengthy task, and there’s quite a lot of them, so reducing maintenance burden is important.”
The IQ Series’ Compressor Wall units, for example, are primarily placed on rooftops as a more traditional air handler.
“They’re more suited typically to larger, new-build operations, primarily in the U.S.,” Brown says, adding that the units are ideal for rooms with more than 1,000 square feet of canopy per room and facilities with more than 10,000 square feet of total canopy area. “We do see some regional differences here. Canada on the whole prefers indoor split equipment because it’s cold and it [is difficult] to maintain units that are on the roof in the middle of winter, whereas the U.S. generally doesn’t have as much of that cold season.”
Split systems—a standalone dehumidification unit plus cooling—is often used in retrofit applications, where there is an existing building that already has cooling available.
“A lot of retrofitted units, particularly in the southern U.S., don’t have the roof [space] available or enough structural load available to put equipment on the roof,” Brown adds. “So, maybe for structural reasons, you go to a split.”
5. Facility Layout
Growers will want to evaluate their facility layout and space considerations, Brown says, particularly in a retrofitted facility, where plans for a dehumidification and HVAC system were not built into the blueprint from the start.
“Particularly in the retrofit world, [placing Quest’s] IQ products indoors takes a lot of space,” Brown says. “If you’ve got a new building where you’ve got the ability to build that infrastructure from day one, that makes a lot of sense. If you’ve got an existing building already divided and you’re sacrificing an area for equipment, that probably doesn’t make sense.”
6. Cost
Cost is certainly a key consideration for growers as they embark on their journey to select dehumidification and HVAC equipment, Brown says.
While the up-front cost of a split system is typically lower, it may not be as efficient or cost-effective to run in the long-term, he adds.
“If you’ve got a facility or a new licensed producer that’s just starting up, capital costs might be more of a concern than operating costs,” Brown says. “It may be something that they retrofit after the fact.”
7. Speed to Market
In some states, there are time restrictions between when a cultivator’s final license is issued and when a first crop must be harvested, or growers may just want to be quicker to market on their own accord, Brown says. In these instances, it may make more sense to go with an off-the-shelf solution rather than a custom-built product like Quest’s IQ Series.
“Although we do have some stock of certain models, most of it is built to order, which can take 8 to 12 weeks,” he says.
8. HVAC Control Systems
Cultivators should also be thinking about how the dehumidification and HVAC systems are going to be controlled or integrated into the rest of the building’s fertigation and lighting controls, Brown says.
“Certainly, from my perspective, it’s probably the thing that we spend the most amount of time on, trying to get the control system understood by all parties involved,” he says. “Sizing equipment is relatively easy, but getting that room to function as a system can be a bit more challenging.”
The grow room should be designed as a system, Brown adds, rather than as a collection of parts, and adding or changing equipment after the fact can be extremely challenging, so planning ahead is key.
“This is more of a mindset than a checklist, and is really advice to the grower,” he says. “You don’t want to have a bunch of disparate systems slapped together in an ad hoc way, but rather an approach to designing a room that looks at all aspects from the beginning—lighting, HVAC, humidification, CO2 control, ventilation, cleanliness, access control and building design. Each one of those things can make or break a grow and need to be considered together during the design phase."
