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The best grow room dehumidifier for your setup

Cannabis grow room with dehumidifier hanging in canopy

Here’s the thing about humidity: It doesn’t care if you’re a basement hobbyist or the biggest, commercial cultivator on the block. It will demand to be managed if you want to have a great indoor grow. So how do you take control?

A number of factors play a role in controlling humidity: room temperature, the number of plants, and how much you water. But, ultimately, nearly every indoor grower is going to need a dehumidifier – or a dozen.

So, how do you know what’s the best grow room dehumidifier for your setup? Is efficiency a top priority? Or what about capacity? Maybe it’s ensuring you have the most reliable system possible.

To help break down the best grow room dehumidifier for hobbyists, caregivers, boutique and commercial growers, we talked with two industry veterans: Gary Howard, owner of Urban Garden Center and managing director of Safe Alternatives Dispensary; and Clif Tomasini from Quest Dehumidifiers.


Transform an unstable growing environment into one that allows you to achieve and maintain precise environmental control.

Hobbyists and humidity

A hobbyist is anyone growing a few plants in their home, perhaps in the basement or a small grow tent.

When it comes to humidity, there is a high likelihood you don’t need additional control if your house or basement is well insulated, equipped with proper HVAC, and free of pre-existing moisture issues, Tomasini said.

“Most hobbyists growing a small number of plants in their home won’t need a dehumidifier. If they do, a small residential unit is likely sufficient,” Tomasini said. “We do recommend these growers monitor humidity as plants mature and water intake increases because a humidity problem can pop up quickly.”

One way to keep humidity down is to avoid overwatering, Tomasini said. Small, residential dehumidifiers can also help but they’re inefficient and unreliable, he said.

Howard added that anyone with about 8 grow lights, which could fall into the hobbyist category, will want to consider a commercial dehumidifier. That’s because the plant canopy begins to significantly increase and will trap moisture.

Often, a unit that pulls 150 pints of water from the air will do the trick for this size grow, but it’s best to size your room based on how much water you’re giving your plants daily.

While it may be difficult to pull the trigger on a commercial dehumidifier, it will pay for itself in money saved on electric bills, he said.

Caregivers – coming to terms with dehumidification

The caregiver category is a broad cross-section of the growing community that often has at least one 10-light room, if not more.

Given the size of the rooms, Howard said humidity control for caregivers is a must. Along with lights and air conditioning, it’s one of the key areas where Howard, a longtime caregiver, would never cut corners, he said.

Humidity control is critical because in this size grow, the plant canopy is much larger than anything a hobbyist is handling. Those plant canopies trap moisture, creating a haven for crop killers like powdery mildew and bud rot, Howard said.

The challenge for caregivers is coming to terms with the fact they need commercial dehumidification.

“We commonly hear this group tell us that they didn’t have a humidity problem as hobbyists, so why would things be significantly different now?” Tomasini said. “Naturally, these customers worry they’re being sold something they might not need. In the end, most growers decide to start with the cheap units to address a humidity problem. It isn’t until those units fail that they look for something more efficient and reliable.”

Howard said a 10-12 light caregiver room usually requires about 300 pints of dehumidification. For that reason, he almost always recommends using two 225-pint units to build in redundancy and to protect against any “worst-case scenarios.”

“I always ask, ‘What are the room dehumidification needs without anything in it, meaning no plants,” Howard said. “Once we know that number, we can add in how much humidity control we need for an active grow. Consistently, we find about 400 pints of dehumidification is perfect.”

Only the best for boutique

For boutique growers, precision is the name of the game, as growers push for the highest-quality product, dialing in terpenes and THC levels.

At this level of growing – usually between 1,000 to 5,000 square feet of grow space – quality and redundancy become the most critical focal points when it comes to environmental controls, Tomasini said.

They’re looking for reliability and performance in every aspect of the grow and that includes dehumidifiers. That’s because one outbreak of mold or mildew, each of which can ruin a grow and cost thousands of dollars, can be prevented by managing humidity.

“For a boutique grower, similar to a craft beer brewer, their reputation and business hinges on the quality of each crop,” Tomasini said. “For that reason, they’re going to want to ensure they have enough dehumidification power to keep their minds at ease.” This is why choosing the best grow room dehumidifier is important.

Because redundancy is critical, Tomasini recommends a modular setup, using multiple units in each room. Often, he sees the best growers using a couple of 225-pint dehumidifiers per room. This provides enough humidity control for all stages of the grow and allows for adequate backup if one unit needs service.

dehumidifier for Commercial growers

Efficiency and layout

For anyone operating with more than 50 lights or more than 5,000 square feet of grow space, managing humidity is a must. The focus for commercial growers is on layout and efficiency, Tomasini said.

“These businesses have chief financial officers and are looking critically at things like electricity usage and depreciation of capital assets,” he said. “They want dehumidifiers built to last and units that deliver a return on investment in no more than one year after purchase.”

As commercial grows have increased in size, many growers are looking for units that pull anywhere from 500 to 1,000 pints of water from the air daily, Tomasini said. Units in this range allow growers to still have the redundancy and customization smaller units provide but with the capacity they need, he said.

“We found a lot of growers want midsized dehumidifiers they can still hang overhead in their rooms, so they can control each microclimate independently,” Tomasini said. “That’s what ultimately led our engineers to design the Quest 506, a unit that meets growers’ needs for a larger-capacity unit that’s still highly efficient.”

The best grow room dehumidifier is an efficient one

Because power consumption is a huge concern for nearly every indoor grower, Howard spends time with each grower he helps to determine the best grow room dehumidifier for their setup. They look at which unit is the most efficient and how to lay out a grow room to maximize performance.

For instance, Howard always makes sure there is proper air movement every eight feet in a room, so dehumidifiers and air conditioners aren’t blowing air on each other, which can make units work harder, costing more money and making them less efficient.

“On a commercial grow, power consumption is huge,” Howard said. “They have to figure it out.

Nobody has unlimited power and nobody wants to spend tons of money.” That’s why the best grow room dehumidifier will always be an energy-efficient one.

Originally published in High Times.



Quest 876

QUest 506