Don't know what the best dehumidifier to install in your grow room? Look no further! Here is a dehumidifier Calculator and sizing guide for your Grow room or grow Tent – Gro Indoor
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Dehumidifier Sizing Calculator for your grow room

by Kunal Khatri 09 Apr 2023

Dehumidifier Sizing Calculator for your grow room

Don't know what the best dehumidifier to install in your grow room? Look no further! This article is going to help you determine the ideal dehumidifier for your grow room. While setting up a grow room, people often do not account for the moisture buildup occurring from your plants transpiring. It's a common enough mistake, albeit one that can prove to be costly.

On average, plants transpire 97% of the water that they absorb. It gives us a basic answer to how much water removal is essential from the room. Your dehumidifier should have the capacity to remove the amount of water you daily give your plants.

Getting a dehumidifier of the correct size is essential to the health of your garden. If you choose a smaller dehumidifier, you could face serious issues, including but not limited to powdery mildew, mold, and pests.

Sizing Your Dehumidifier Things to Consider

There are two essential things to take into consideration when you are determining the size of your dehumidifier:

  • Pints removed per day
  • BTUs produced

You need to be aware of both measures to choose a dehumidifier that works for you.

Pints removed per day

It is an essential thing to consider when you choose a dehumidifier for your grow room. You need to know how many pints of water the dehumidifier can remove from the place where you're growing your plants. We'll explore this in detail below, but it's important to recognize this because you'll see this a lot when you start looking for dehumidifiers.

BTUs produced

The next important thing to keep in mind is the BTUs that your dehumidifier will produce and whether it is suitable for your growth room.

BTU is an abbreviation for British Thermal Units, which is a unit of measurement of heat. BTUs produced refers to the amount of heat that is produced by any equipment.

If your dehumidifier is producing too much heat for your grow room, that could lead to creating adverse conditions in which your plants could die.

What would be the ideal size of my dehumidifier

While determining the ideal size, there are some necessary calculations that you need to do. First, you need to estimate the amount of water that you're giving plants daily. For instance, if there are 30 plants in your garden and require a gallon of water each day -- you'll need a dehumidifier that can remove 30x1=30 gallons of moisture from your room.

Dehumidifiers have ratings in terms of pints. Therefore, you'll need to multiply the total gallon amount by 8 to get a figure in pints. In this example, this translates into 240 pints. So, you'll need a dehumidifier that can remove 240 pints of water.

If your plants grow in soil and provide water every alternate day, you need half the total amount of pints to get an average for a single day.

What if I have a hydroponic system?

If you are using a hydroponic system, you'll still need to do the same calculations as given above. Just consider the water capacity of your system and any reservoirs that don't have a lid. You'll need to divide the number you get by 7 (number of days in a week). Your plants will not consume all the reservoir water, so don't make the mistake of assuming that they will.

The chances are that you'll be topping off your reservoir or changing it out every 7-9 days. Therefore, you need to do the division given above to get a more accurate measure of the ideal size. We've found that using the calculation shown above yields a size that's better suited for hydroponic systems.

We also strongly suggest that you cover your reservoirs. It will prevent your plants from getting contaminated and any possible excess of humidity in your room.

Other Factors to Keep in Mind

We've covered the essential factors to consider when buying a dehumidifier, but there are other things to consider as well. For example, if you have an air-conditioner and your room is sealed, keep in mind that the a/c will remove moisture. In this case, you need to check the specifications of you're a/c and find out how many pints it removes. Once you know that, you can simply subtract that number from your calculations.

Using carbon dioxide in your room will serve to increase the level of humidity. Also, if you have an air exhaust in your room, your dehumidifier will be less effective. Either way, consider increasing dehumidification performance.

How do I size a dehumidifier for a drying room?

Before getting into the calculations, you need to know right off the bat that a standard unit will not be useful here. In this situation, desiccant units are far more useful as they can withstand the stress of high levels of atmospheric moisture. Suppose you are looking for a dehumidifier for a drying room. In that case, you may be thinking that a bigger dehumidifier can make the drying process faster. A bigger dehumidifier will dry out your buds faster for sure. But that isn't the best thing for your flower! You need to go low and go slow at all times, especially when you're drying your cannabis. If you dry out the buds in haste, they'll lose their potency, their flavor, and most importantly, the high! However, suppose you have a big, enough drying room. In that case, the chances are that you will need to dehumidify to a certain level. You have to know the weight of the cannabis while it's wet to get an accurate number for how much you need to dehumidify your grow room.

For example, if you have 100 pounds of wet cannabis, it'll lose approximately 80 pounds. Usually, 80% of the fresh flower's weight is water, which will evaporate while being dried. It's safe to assume that the surroundings will absorb around 60-70% of that water during the initial days of drying. On average, this means that 7 gallons of water will be evaporating. Convert this into pints, and you get 56 pints. So, you'll have to get a dehumidifier that has a rating of at least 60 pints per day. This article assumes that you're operating in ideal drying conditions: 60 degrees Fahrenheit and 60% humidity. To learn more about this, check out our guide on drying and curing.

Last thoughts

Keep in mind that getting the ideal dehumidifier is determined by how much water you bring in to your room daily. The amount of water that comes in is the amount that needs to go out, and you need a dehumidifier that can do just that. If you're still confused, reach out! We can help you determine the ideal size for your dehumidification needs so that your grow room can thrive. Be sure to go to our complete guide on grow room atmosphere and ventilation. It'll help you determine if you even need a dehumidifier.

May 4th 2021
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