Dehumidification Explained

The number one reason for climate control failures in an indoor grow facility is inadequately planned dehumidification. To ensure your humidity control system is selected with enough capacity, we need to take a deeper dive into your desired milestones for each stage of growth.

The key to getting this right is to understand the fundamentals of the relationship between temperature and humidity. As temperature increases, humidity decreases, and vice versa.

A critical climate control measurement and possibly the most important metric in a grow room is VPD, Vapor Pressure Deficit. VPD is the difference between how much moisture is in the air vs. how much moisture the air can hold.

Having equipment specialized for efficient temperature control, combined with an independent dehumidification system optimized for growing conditions, is the most efficient way to achieve an optimal VPD for maximum yields.

As it relates to dehumidification, the two primary technologies currently used in cannabis cultivation are Refrigerant and Desiccant. Each has its strengths and weaknesses depending on the climate a grower is trying to keep.

How Can I Choose the Best Grow Room Dehumidifier?

When researching the market, there is an excellent selection of different options which you can choose from.

However, due to the overwhelmingly increased choices that are available in the market, it is easy to choose an inefficient option, but there are some factors that can help you choose the best grow room dehumidifier.

Specialized Dehumidifiers

One crucial factor to consider is what purpose the dehumidifier is tailored to. If you are looking for one for cannabis cultivation, then it is essential to choose a dehumidifier that is designed to perform the best for cultivation purposes. The primary criteria are units that do not consume valuable floor space, with a method to be hung over head.

These types of dehumidifiers are designed to remove water from the air and provide the cannabis plants with the best conditions, which will guarantee optimal plant growth. For some, this means maintaining humidity setpoints in the 50 – 60% range, while keeping temperatures between 65F – 75F. For these lower set points, desiccant type dehumidifiers are more efficient than refrigerant models.

Furthermore, the reduction in humidity under these specific conditions is also optimized to be energy efficient and is designed to ensure the best crop yield due to the optimal environment it sets for the grow room cultivation. Refrigerant based units will operate more efficiently at their stated capacity of 80F and 60% Relative Humidity.

Number of Plants in the Facility

In addition to that, the number of plants that are present in your grow room is also essential to factor in when looking for a dehumidifier.

This is because the amount of cannabis that is being grown in your grow room will affect the power required and the capacity which is required from the dehumidifiers.

What this means is that the more cannabis plants you have, the more water will be dispersed into the atmosphere through the plants, which will increase the work the dehumidifiers must do in order to manage the moisture in the atmosphere.

Your Method of Cannabis Cultivation

Due to the advancements and innovations in technology in current times, there are many different methods and techniques for cannabis cultivation that have varying results.

These different methodologies include Low-Stress Training (LST) and other techniques that will also need to be kept into account, primarily due to the varying humidity each of these methods requires in order to perform with maximum efficiency.

Size of Grow Room

It is not necessary for each grow room to be of the same size. There are many rooms out there that are different sizes, and the scale of their dehumidification systems also varies accordingly.

Refrigerant Based Dehumidifier

Refrigerant-based dehumidifiers have been the standard in the cannabis industry for years. When broken down to their base operating principles, they are an Air Conditioning unit in a box.

The compressor lowers heat from the refrigerant and flows the refrigerant through an evaporator. An evaporator condenses water due to the low temperature of the refrigerant, and the water is drained away. A fan consistently pushes air with high humidity across the evaporator.

The condensate can be collected and drained to a collection tank for reuse while the air returns to the grow room dry and slightly warmer with the waste heat from the power consumed during this process.

Dehumidifier Rating

Refrigerant dehumidifiers are rated to perform around 80°F and 60% relative humidity. The PPD, pints per day, and ratings on most available refrigerant-based dehumidifiers are based on those numbers.

If the temperature or humidity goes below the rated specification, the amount of water removed can drop dramatically. For example, when the temperature drops from 80F and 60% RH to 70F and 50% RH, you will realize a reduction in the capacity of about 40% on average.
Some flower and veg spaces are kept near the 80/60 level, so the reduction in capacity might not be an issue. If you, as a grower, want improvement in your humidity levels, we recommend increasing the temperature to lower humidity and improve the performance of your dehumidifier.

Desiccant Based Dehumidifier

Desiccant pouches are commonly used in packaged food to aid in preservation. A desiccant dehumidifier has a similar medium that collects water from the air as dry air comes out the other side. The desiccant is then transferred to another air stream where the moisture is rejected outside.

The best use for desiccant dehumidifiers is in spaces that require lower temperatures. While refrigerant dehumidifiers drop by roughly 40% when temps drop from 80F to 70F and humidity from 60% to 50% RH, Desiccant-based units will typically only drop by about 15% to 20%.
That makes this ideal for dry rooms, which typically have temperatures and humidities in the lower 60s. Also, many growers prefer lower temperatures later in the flowering process, making desiccant dehumidifiers a serious consideration.

Until the release of the new EasyDry dehumidifiers, desiccant dehumidifiers have been overpriced and often too dimensionally large to fit a grow room.

EasyDry dehumidifiers are compact to fit any space a more traditional refrigerant-based model would fit and can be ceiling suspended, all within a reasonable price range.

Conclusion

Every commercial cannabis facility has unique needs and challenges to create the preferred climate for the grower.
Easy Root is a team of engineers that are able to help design a facility to take on those challenges and deliver a unique solution. Reach out to us to provide a complete climate control solution for your upcoming growth.

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