Quest Dehumidifiers’ Clif Tomasini says that many cultivators typically lean on knowledge from other applications to build out their grow rooms, but that knowledge doesn’t always transfer in terms of dehumidification.
“Our homes typically have a cooling and heating system. Logically we apply what we know from that environment, to the cannabis environment,” Tomasini says. “The key is to remain open minded. Some things we do in our homes may not work so well in a grow room. Being open minded is the first step."
Below, Tomasini discusses some of the major considerations cultivators must keep in mind concerning humidity and humidity control as they build out their cannabis grows.
1. Don’t Rush Your Plans.
“For some people, there’s so much excitement, that they tend to want to hurry to get to the finish line, and often, that’s coming at a compromise of making some mistakes,” Tomasini says. “Let’s say you had a 100,000-square-foot facility, or even a 20,000-square-foot facility, you spend all your money trying to fill it up. Maybe if you only built out a quarter of that, but you did it right, you’d be much better off, and therefore, you generate the revenue to fund the completion very quickly.
“Obviously, we know profits in this industry are pretty good—in most cases, you can sell everything you grow, so that’s why people tend to want to build out the full facility,” he continues. “And often, they don’t have the money, so they make compromises. Humidity control is one of the things they often compromise. In the end, many growers end up with a large harvest of unclean or unpure cannabis.”
2. Find the Right Consultants.
Sometimes finding the people who can best advise you can be a challenge. “Who are the right people? That’s a tough one because what is the definition of the right person?” Tomasini says. “Is it an engineer, an architect? Is it a closet grower? I believe that talking to the right people is paramount. If you’re talking about lights, you’re going to talk to the company that’s an expert in lights; if you’re talking about building insulation, you might talk to somebody who’s an expert on insulation. When it comes to humidity, there’s only a few experts, and we consider ourselves to be the company who’s done it the most. We never charge for explaining humidity and humidity control and have factory reps across the country who can provide onsite consulting. Again, we don’t charge for our time or knowledge and want to make sure growers are successful from the start.”
When you’re vetting someone to advise you on your grow room build-out, it’s best to look for substance in their sales pitch. “A lot of people are very charismatic, and there are some very smart people, but when it comes down to it, [you must ask yourself] ‘Are they talking about philosophy, or are they talking about the details?’ A lot of the companies only talk about philosophy,” he says.
“For example, everyone knows you need to be energy efficient. No one would argue that at this point,” he continues. “So every booth [at a trade show] is going to say, ‘We build efficient products.’ Well, that’s meaningless information. What is your definition of efficient? It’s like going to buy a car … You need to give me the miles per gallon.”
For HVAC, that efficiency definition includes a SEER rating (Seasonal Energy Efficiency Ratio). Humidifiers are measured in pints per kilowatt hour, which Tomasini explains as: How many pints of water do we take out of the air for every kilowatt-hour we use?
“I would ask for the efficiency rating,” he says. “If it’s the cooling system, they’re going to pull out the spec sheet; they’re going to tell you what their SEER rating is. If you can’t find the SEER rating for a cooling system or pints per kilowatt for a dehumidification system, be skeptical.”
3. Understand the Difference Between Indoor and Greenhouse.
“This applies to all HVAC, not just dehumidification. But the region you’re growing in is the single most important detail,” Tomasini says.
“In an indoor grow, it doesn’t matter if we’re in Canada, in the middle of winter, or Arizona in the middle of summer. The architects and engineers have put in the insulation and equipment so that we always feel the same. We’re always comfortable. In a grow room indoors, same thing. If you’ve got the equipment right, and the insulation and the building details right, which you probably do, they’re just probably already present, and it’s a given. You can replicate things very easily because it’s all insulated from the outside environment. So indoor is very similar from place to place.
“But in a greenhouse,” he continues, “you don’t have any of that. … The whole building science part is missing. So if you try to take a greenhouse that works very well in Arizona and put it north of the Mason-Dixon line, it’ll probably perform terribly.”
He gives the example of the dry climate of Arizona, where a cultivator needs humidifiers to put some humidity into the air. In contrast, a grower in a more humid climate will need a stronger dehumidification system to suit their region’s grow atmosphere.
4. Know Your HVAC Terminology.
You want to walk into an HVAC consultation equipped with the basics so that you know you’re having a quality conversation with your potential supplier. Here are a few examples to get you started:
Pints per kilowatt hour. “It’s like miles per gallon,” Tomasini says. “The higher the number, the more efficient. Look for this when evaluating you dehumidification solution.”
SEER rating. A Seasonal Energy Efficiency Ratio (SEER) rating is the cooling output during a typical cooling season, divided by energy input during the same period. The higher the SEER rating, the more energy efficient a unit is.
Heat load. This is measured in BTUs, British Thermal Units, which sounds odd, but it’s simple, he says. One BTU is enough heat to raise the temperature of one pint of water by 1°F. At least know that the higher the number, the more heat is involved, so you definitely want to account for that in your cooling needs.
Latent heat. This is the energy absorbed by or released from a substance during its change of phase; for example, from a liquid to a vapor (or vapor to liquid).
Sensible heat. This is the energy needed to change the temperature of a substance with no phase change. The temperature change can come from infrared light hitting the soil or from warm air. Sensible heat is heat that you can feel (that you can sense).
Vapor Pressure Deficit. VPD is the difference between the amount of moisture in the air and how much moisture the air could potentially hold when it is saturated, typically measured in pounds per square inch (psi) or kilopascal (kPa).
Image courtesy of Aloha Green
