Water Chillers for Hydroponics (The Ultimate Guide)

As a hydroponics newbie back then, purchasing a water chiller came to mind. Of course, as a beginner, I was curious about exploring the best conditions for my deep water culture (DWC) veggies and herbs. I know you are too! Thus, this guide will teach you about my water chiller exploration takeaways.

In general, water chillers are best for commercial deep water culture hydroponic production. They are not required for home-based hydroponics gardening. The only case water chiller might be needed for a small system is in case of high ambient temperature that brings the solution above 75F.

Water chillers seem to be a great investment. But what should you consider before buying it? Are there any cheap or manual alternatives to regulate the temperature of your hydroponic solution? Buckle up, because I will provide answers!

What are Water Chillers Used for in Deep Water Culture?

Water chillers are used to control the temperature of the nutrient solution to aid proper plant growth in hydroponic systems, including, but not limited to, deep water culture (DWC) hydroponics.

Just like the standard industrial chillers, hydroponic water chillers also consist of cooling coils that chill the nutrient water that circulates through them.

If you are operating a commercial-scale hydroponic system, using water chillers might be the best option for you. Most models also operate using remote technology that monitors and regulates the temperature in your water reservoir.

At this point, you may be wondering. How about those who do hydroponics as a hobby? Of course, I’ve got you covered! I will reveal tips and tricks you can do before the end of this article!

When to Use Water Chillers in Deep Water Culture Hydroponics

Generally, water chillers are recommended for locations with hot climates. More specifically, they should be used when the surrounding and water temperatures consistently exceed the recommended 65-75⁰F.

Water chillers are not required for every hydroponic system. My advice for you is to first monitor your surrounding temperature and water temperature for a week to a month before purchasing a water chiller.

One of the best practices I do in my garden is to place thermometers. This practice will surely help you monitor whether or not you are giving your plants the right temperature.

Afterward, ask yourself all these questions:

1. Does the average surrounding and water temperature exceed the optimum for hydroponics for a long period of time? (If your answer is yes, buy a water chiller.)
2. Is the temperature reading within the best range for my specific veggie and/or herb? (If your answer is no, consider buying a water chiller.)
3. Are there still other possible ways to control the surrounding and water temperature? (At this point, if your answer is no, run to the store and buy a water chiller! But you may be asking: What are the alternative ways to control temperature? I will discuss this later.)

3 Types of Water Chillers for Hydroponics

The three types of water chillers are 1) drop-in, 2) in line, and 3) thermoelectric. Though all three can be used with deep water culture (DWC), some are best suited for specific hydroponic systems.

1. Drop-In Water Chiller

A drop-in hydroponic water chiller is a space-saving option as it can be hung. It works by using a thermostat that regulates temperature. Drop-in water chillers perform well in deep water culture (DWC) hydroponics, but they are also compatible with most systems. It is also a cheap option which is ideal, especially for beginners.

Drop-in water chillers are great for deep water culture because they are easy to use. You can just hang it above your hydroponic water reservoir, and then you are good to go!

Since a deep water culture system usually uses a bucket, moving it with this type of water chiller will be made easier.

Below is an example of an available drop-in water chiller on Amazon.

2. In-Line Water Chiller

In-line water chillers use filters that adjust the temperature while the nutrient water is circulating within the deep water culture (DWC) system. This type of water chiller is most compatible with nutrient film technique (NFT) compared to other hydroponic systems.

If you are a garden newbie, this type of water chiller might not be the best for you. This is because it requires plumbing experience, making it more appropriate for large hydroponic systems.

In-line water chillers are best for the nutrient film technique because they run specifically for complex hydroponic systems. They use a lot of horsepowers, making them practical for large systems only.

Below is an example of an available in-line water chiller on Amazon.

3. Thermoelectric Water Chiller

Thermoelectric water chillers do not consume much space and are also a quiet option for deep water culture (DWC) hydroponic systems. They work by transferring heat between two electrical junctions, thereby cooling the hydroponic water.

If you have a small hydroponic system like deep water culture (DWC), this one might work the best for you!

Aside from that, it is also relatively cheaper compared to the ones above. Below is an available thermoelectric water chiller on Amazon.

How to Hook Up a Water Chiller to Your Hydroponic System!

Importance of Water Temperature Control in Hydroponics

Temperature affects the metabolism and nutrient uptake of plants, thereby having the ability to change its composition. For instance, a study on hydroponic lettuce revealed that plants cultivated in a cold environment had 20% higher dry matter content than those produced in warm settings.

Your nutrient solution should be maintained at a steady temperature of 65-75⁰F.

Always remember that a hot nutrient solution breeds bad bacteria. Also, an increase in microorganisms will be bad for the tender roots of the plants.

On the other hand, the plants will grow slower if maintained at very low temperatures as the roots will begin to shut down. In this case, they will not be able to get enough oxygen in cold nutrient solutions.

By this time, I believe that you already know that each crop requires a certain surrounding temperature—some plants love hotter climates while some are the best fit for cool-climate areas.

Pro Tip: Lettuce thrives in a flexible temperature range of 7℃ to 21℃. Spinach and chives grow best at 18℃ to 21℃; kale and basil at 15℃ to 25℃; strawberries at 13℃ to 21℃; tomatoes at 22℃ to 26℃; peppers at 23℃ to 26℃; and cucumbers at 22℃ to 24℃.

3 Cheap Alternatives for Water Chillers

Other cheap alternatives to control surrounding and hydroponic water temperature include 1) using a fan in the growing room, 2) putting ice packs or cold water every 10-15 minutes, and 3) painting the water reservoir white.

1. Use a Fan

Using a fan can ensure the flow of cooler air by providing the hydroponic plants with ventilation.

Maybe you are wondering: What type of fan? Do not worry! You can use a normal electric fan for this.

This option will ensure that the temperature in your growing room is cool, thereby also decreasing the tendency of having hot nutrient water.

But if you really want to improve the temperature regulation in your grow room, you have the choice to install an inline extractor fan.

An inline extractor fan takes hot air and ducts it out of the growing room. Because heat rises, your extractor fan should be placed at the top of your room.

2. Put Ice Packs or Cold Water

Keeping 10-15 ice packs on hand and adding one to the water reservoir of a hydroponic system every 15 minutes until the appropriate temperature is attained is a simple and affordable option.

However, when temperatures are particularly high, this approach may become time-consuming. It is also unlikely to be a feasible solution for bigger gardens.

Adding cold water to the hydroponic solution is another simple remedy.

But this step comes with another responsibility. Keep in mind that every time you add water, the nutrients will be diluted; thus, check and adjust your electric conductivity (EC) as needed.

   Learn more about managing nutrients in our article about hydroponic nutrients. 

3. Paint Your Water Reservoir White

Coating the hydroponic system’s reservoir with white paint can stop the increase of nutrient water temperature because white surfaces do not absorb heat.

This is the reason why polystyrene or styrofoam boxes are used as deep water culture hydroponic systems. Using them takes advantage of their white color and their property as an insulator.

Are Water Chillers Worth It?

Using water chillers in a commercial hydroponic farm is worth it because it lessens the additional workload of regularly monitoring temperatures in every water reservoir. However, for home gardening, it is not practical to use water chillers.

If you are just doing home hydroponics gardening, it is more practical to try the cheaper alternatives I mentioned before.

But if after all of those steps, you still find it difficult to control your temperature, that is the time you may consider purchasing a water chiller.

As a reminder, you can use drop-in or thermoelectric water chillers for deep water culture (DWC) hydroponics. But these two options can also work for other small hydroponic systems.

FAQs

What should the water temperature be in deep water culture (DWC)?

In deep water culture, the nutrient water temperature must be maintained from 65 to 80°F. Temperature higher than that could cause the proliferation of bad microorganisms. Meanwhile, cooler temperatures would result in slower growth and development. Learn more about this in our article on the best temperature for deep water culture.

How cold is too cold for hydroponic water?

The ideal low-temperature range for hydroponic water is 65 to 68°F. If your hydroponic solution goes lower than that, it would cause the shut down of root function. When this happens, the roots will not be able to deliver water and nutrients to the different plant parts, causing slower growth and further death.

When should I change my deep water culture (DWC) hydroponic water?

Hydroponic water in DWC can be changed every 1 to 2 weeks. This is necessary because your veggies and herbs use a portion of the nutrient water daily. Thus, refreshing your hydroponic solution will ensure that your plants are getting enough nutrients and water supply. Learn more about this in our article how often should I change my hydroponics water.

Summary of Water Chillers in DWC Hydroponics

Water chillers are used to regulate the temperature in a hydroponic reservoir. They are usually used in large-scale hydroponic systems such as deep water culture (DWC). However, when temperature becomes difficult to control in areas with hot climates, they could be helpful for small-scale hydroponic gardeners as well.

There are three types of water chillers: 1) drop-in, 2) in-line, and 3) thermoelectric. Drop-in and thermoelectric water chillers are compatible with most hydroponic systems, especially deep water culture. Meanwhile, in-line water chillers are best for commercial hydroponic farms with nutrient film technique (NFT) systems.

Cheap alternatives such as 1) using a fan, 2) putting ice packs or cold water, and 3) painting the reservoir white can also help in regulating nutrient water temperature.

Sources

• “Development of Hydroponic Root Zone Cooling System for Selected Vegetables Cultivation Under Crop Protection Structures” by Sulaiman, A.S.S. et al. in Precision Agricultural Programme, Engineering Research Centre, Malaysia
• “Effect of temperature on composition of hydroponic lettuce” by Gent, M.P.N. in Acta Horticulturae
• “Heating requirements for winter hydroponic lettuce production” by Miller, A. et al. in Purdue University Extension
• “Nutrient Solution Temperature Affects Growth and ◦Brix Parameters of Seventeen Lettuce Cultivars Grown in an NFT Hydroponic System” by Thakulla, D. et al. in Horticulturae
• “Quickchill: Thermoelectric Water Cooler” by Chua, F.L. et al. in Santa Clara University