What Are The Best Water Chillers For Hydroponics?

One of the common troubles Hydroponic growers face is the high temperature of the nutrient solution. The temperature is critically important, but most people overlooked.

Using a water chiller is the most efficient choice when it comes to bringing your system’s temperature down.

Gone are the days when water chiller possession is only limited in commercial production because of its high cost. Now many affordable but effective options are available on the market for indoor growers and hobbyists.

In this post, I will help you answer when you need a chiller, why you need it, and help you choose the best hydroponic water chillers on the market.

Quick Product Table

What is a water chiller?

A water chiller is an external unit whose purpose is to lower the temperature of the system you install it to.

It often has a thermostat that measures and lets you know the temperature of the water in the container.

In fact, the word “chiller” is quite a misnomer term. You must understand how it works to know how it is not really a “chiller” – it does not bring or blow any cool or cold air, but remove heat instead.

Why use a water chiller?

Controlling temperature is one of the most effective ways to control your crop’ yield and performance.

The water and the nutrient solution are the heart of your system.

And temperature is one of the most common issues that happen in the water system.

Warm water decreases its ability to hold oxygen, which means less dissolved oxygen in the nutrient solution. This severely affects the root growth. Also, there will be more chances of diseases and pathogens.

Cooling the nutrient solution can be as easy as throwing some iced bottles to reduce the system’s temperature temporarily, but it’s not efficient and hands-off.
Fortunately, the water chiller, if you can afford it, is no doubt the best solution and can also fit any hydroponic and aquarium size.

When should you get a water chiller?

If you, human beings, need an air conditioner, your hydroponic plants need a water chiller.

Many factors could bring in a high temp in your system – the weather in your city gets too hot, especially in the summer; the pump runs continuously, causing lots of heat.

Grow lights emit heat too. And in fact, in a closed grow room area, they are the factor that causes the most heat.

A CO2 burner, air handlers, dehumidifiers also add heat to your system.

Keep in mind that the ideal environment for growing is
air temperature at 75 – 80F, and root zone at 68oF or less

If the temp of your system, where the roots stay has drifted too far of 68F, it’s time to chill it.

Pros and Cons of using a water chiller

Pros

Dissolved oxygen in the nutrient solution. Warmer environment decreases oxygen level, which in hands reduce the chance of living of any inhabitant living inside. If chilling is the primary purpose of water chiller, it has done the job absolutely well.
Automate the process. When your system is still small, you can watch and chill it manually when the heat rises. But what happens when you have a larger one, or when the ambient temperature has got out of control? It’s better that you get a water chiller and let it automatically bring the heat away without any hassle of checking or worrying about plant roots’ death.

Cons

Heat. The water chiller is actually a mini refrigerator. It puts out heat. That’s why you should not place it near the growing area to keep energy efficient.
Expense. In fact, the biggest reason against water chiller is it’s a quite an investment even though it has become much affordable over the years. Unless you are a commercial grower, hobbyists, or someone who know exactly how a water chiller can bring high ROI (return on investment) to your system, other inexpensive chilling methods can be used instead.

How to accurately size the chillers for your hydroponic systems?

Determining the size of water chiller beforehand is very important as you cannot use the same size of the chiller for all systems.
Oversizing it will make the chiller cycle more often. This will consume more electricity.
Meanwhile, an undersized one will never properly cool your system.

Cooling/Chilling ability is measured in BTUs (British Thermal Units) or Tons (BTU per hour/12000). One BTU will increase 1 pound of water by 1oF.

The higher BTUs a unit has, the quicker it removes heat than the one with a lower BTU.

Often, on their website, each manufacturer will list out the important areas to fill to calculate the sizing approximately.
If they have, you should check to know immediately the size that fits you.

But in case you want to find out the BTH/h you need to know the size you want, I will also give a specific guide here.

Note:
The process of sizing an exact BTU needed is quite complicated and tricky, and the truth is it cannot be 100% correct because there are lots of factors involved like heats of ambient rooms, grow lights, dehumidifiers, etc.

But spend a little time as it’s essential to check the approximate BTU you need for your system. And it is not hard to do the calculations.

Let’s compute the BTU per hour.
Here’s the formula:

BTU per hour = Gallons per hr x 8.33 (weight of a water gallon) x Temperature Differential (in an hour)

We’ll break down each unit.

BTUs per hour. We are measuring the BTU increased in an hour.

Gallons per hour, or flow rate of the pump per hour.

The temperature differential is the change in the incoming water temperature and the water temperature you desire. This is to compute how much heat all equipment add to the system in 1 hour.

For incoming water temperature, you should get the hottest temperature your nutrient solution can have on the hottest day, including all the heat from everything that can give off (like grow lights, pumps).

The desired temperature is the optimal one you want for your system. Typically, it would be about 60 – 68oF.

Now, time to give an example with numbers for clearer clarifications.

Let’s say I have a system of 50 gallons of water.
On its hottest day with all equipment turned on and all heat emitted, the temperature recorded is at 75oF.
Then, I bring down the system temperature to my desired one at 60oF by throwing some frozen water bottles not to add more water to the system.
Now, take away all chilling frozen bottle, and record the temperature after one hour. The temperature I measure is 70oF.

Now I have had the change in temperature within 1 hour: 70 – 60 = 10oF

Therefore, the BTU/h = 50 (the gallon of water) x 8.33 x 10 = 4165
You will need to back up in case your system can be hotter. We’ll add 20% to the total BTU/h.
Total BTU/h= 4165 x 1.2= 4998

If you want to convert into ton unit, here is the conversion formula:
Because 1 ton of cooling = 12,000 BTH/h, then 4998 BTH/h = 0.4165 tons

What about Horsepower unit?

Measuring in terms of BTH/h and tons makes it easier for customers to choose as it lets them know how many refrigeration tons of ice a water chiller can make.

However, in reality, it’s not the case.

You will see that most chillers sold on the market are measured in horsepower (HP). But horsepower only shows you the compressor size/capacity of the chiller. It just gives you an overall idea of how strong the system. It doesn’t tell you the actual converted energy provided with the actual temperature and the desired temperature you want.

In a technical explanation, horsepower and BTH/h are two different measuring unit to convert.
Horsepower is a power unit, letting you know how much power a machine consumes.
Meanwhile, BTH/h is a refrigeration unit, telling you the refrigeration rate of the machine per hour.

So when you say 1 HP = 9000 BTH/h, it should be put correctly that with the refrigeration rate at 9000 BTH/h, the machine power of the chiller is 1 HP.

Because HP and BTU/h are different units, that explains why 1 HP can be converted to different BTU with different chiller machines. The higher each HP can be changed into BTU, the more energy efficient your chiller is.

For example, Some water chillers only have 9000 BTU/h for 1 HP.
Meanwhile, another can bring in up 12000BTU/h for 1 HP because it owns an efficient technology.

So if the manufacturers disclose BTH/h or ton, you can follow our guide above. They are a more accurate way to know how good a water chiller machine is.

If they only disclose the HP,  you can follow the manufacturer’s recommendations for the gallon sizes.

Or you can just guess how many BTUs for each HP. Commonly, 1 HP = 9000 -> 12000 BTU/h (depending on the technology and how efficient it is).

Let’s say if you calculate that you need 4998 BTH/h, you’ll need a 0.4 – 0.5 HP chiller machine.
To be safe in case my system is larger or hotter in reality. I’ll get a 0.5 HP water chiller.

Top 5 Water Chiller for Hydroponics

Wrapping up

Choosing a water chiller for your hydroponic system is not an easy choice with many options on the market. By spending lots of time for researching and talking to manufacturers, the JBJ Aquarium Arctica Titanium Chiller is our favorite chiller that is powerful, energy-efficient, long-lasting, and have a long warranty period.

If you are looking for a less expensive chiller but can produce excellent performance, the Active Aqua chiller is the perfect option.

The IceProbe is a perfect budget-picked chiller for hobbyists, and small hydroponic or aquarium growers.