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9 Ways to Cool Your Grow Lights

Grow lights are an innovative solution that helps simulate indoor plants’ climatic conditions by providing the right light spectrum for photosynthesis. However, these lights can sometimes become too hot, compromising grow room conditions by increasing the temperature to a point that is dangerous for your plants. Since you can’t remove the lights (because plants need light for photosynthesis), you’ll need to learn how to cool your grow lights or your grow room to maintain optimal temperatures.

Here are 9 tips on how to cool your grow lights:

  1. Use cooled reflectors.
  2. Reduce the number of lights.
  3. Improve the room’s insulation.
  4. Have a well-ventilated space.
  5. Open grow tent vents and doors.
  6. Increase air circulation with fans.
  7. Use air conditioners.
  8. Use the lights at night.
  9. Get an environment controller.

The rest of this post will cover these tips in greater detail and provide guidelines for choosing the right solution for your grow room or tent.

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Photo of grow lights hanging above pepper plants in a grow tent
Photo of my grow lights hanging over my pepper plants in a grow tent. Photo by Spicy Trio

Tips for Cooling Grow Lights

1. Use Cooled Reflectors

Light reflectors are among the most popular equipment in a grow room. They improve the efficiency of your non-LED grow lights by focusing the light energy on the plants, helping reduce your overall energy bill.

Additionally, cooled reflectors reduce the heat flowing through the grow room. They achieve this through the use of an air or water cooling system. Air-cooled reflectors are the more popular of the two.

With the air-cooled reflector, a glass barrier is introduced over the reflector hood holding back the heat from the bulbs within the hood. The cooled air that flows in from the air ducts cools the space while also pushing some hot air out of the expeller-end of the air duct.

This system can single-handedly reduce the heat from your non-LED grow lights by a significant margin.

2. Reduce the Number of Lights

This is more of a “common sense” approach to the problem. If the lights begin to make your grow room too hot, a simple solution can be to reduce the number of lights you have at any time.

The downside is that with fewer lights on, some of your plants may not get enough light exposure. You may then have to alternate the lights so every plant can have some time of exposure to the lights.

Another way to deal with making sure your plants are getting enough light with fewer lights is by installing grow light movers, like this one found on Rather than alternate the lights you put on, light movers will automatically move the lights around. This way, fewer lights will serve a more expansive space and significantly reduce the risk of hot spots.

3. Improve the Room’s Insulation

Sometimes, the heat in the room is not necessarily from the grow lights alone. If the grow room is poorly insulated, heat from outside can add to what the lights are already producing.

After properly insulating your grow room you may notice things cool down a bit inside as long as you made sure to properly ventilate your grow space.

4. Have a Well-Ventilated Space

A properly insulated room with grow lights can quickly get very hot. Improving heat exchange with an external source can help you manage the temperature in your grow room.

You can achieve this with the help of an air conditioning system controlled by an appropriate thermostat. While this will increase some of your costs, it is an efficient way of keeping the temperature of your grow room just where you need it to be.

Another way to improve ventilation in your grow room is by installing an efficient venting system with suitably powerful fans. These will suck in cool air and expel hot air. To make the system a lot more efficient, you can connect it to an automatic temperature control that will turn the fans on or off to maintain the required temperature.

Aside from regulating the temperature in your grow room, a proper ventilation system will help you manage relative humidity more efficiently. As your plants transpire, moisture is released into the room. In addition to any condensation that may occur because of the heat, this can cause moisture buildup, which is unhealthy for your plants.

With proper ventilation, moisture can be extracted from the room before it condenses, keeping the humidity in the room balanced.

Another reason why proper ventilation or air circulation is essential is that it ensures a constant supply of fresh CO2. This prevents stagnation of CO2 around the plants, helping keep the temperatures low.

Photo of a grow tent with pepper plants inside
This is my grow tent, I’m growing Shishito, Jalapeno, and Carolina Reaper peppers. Photo by Spicy Trio.

5. Open Grow Tent Windows and Doors

Another way to ensure proper ventilation is by keeping the windows and/or doors of your grow tent or room open. This simple action will immediately improve air movement, cooling the temperature within the grow space. This approach will be more efficient if the location of the windows and doors encourages cross-ventilation, and is especially important when grow lights are being used.

6. Use Fans to Increase Air Circulation Within the Room

Aside from increasing heat exchange with an external cooling source, it is also vital to improve air circulation within the grow room. A good approach will be installing fans (stationary or oscillating models). These will blow directly under the lights, improving circulation and redistributing the light’s heat.

7. Use Air Conditioners

Air conditioners come in handy in controlling indoor temperatures in various situations, and your grow room is no different. They can help maintain the temperature in your grow tent or room at the desired level. While air conditioners may be more expensive than fans, they are more effective at cooling indoor spaces in sweltering conditions. Having a cooler room will help keep your grow lights cool.

8. Use the Lights at Night

In many cases, temperatures are cooler at night than during the day. This being the case, using the lights at night when the general temperature is cooler can be a solution to consider. With the external temperature being cooler, it will take much more heat from the lights to heat up the grow room. You can set this up with a timer to help ensure that the plants get as much light as they require.

In addition to helping you manage the heat in your grow room, using the lights at night will reduce your spending on energy bills. You will not only reduce the number of hours you’ll have the lights on, but you will also have them on at night when energy providers usually charge less.

9. Get an Environment Controller

This is the most comprehensive solution you can incorporate into your grow room. With an integrated environment controller, you will not only take control of your grow lights but also have automated control over the CO2 levels, room temperature, relative humidity levels, and more.

This complex solution will also be expensive, so it will only make sense for some types of grow rooms, especially commercial ones. With this system in place, every variable is automatically managed to ensure that your plants get the best environment to flourish and yield optimally.

Choosing the Right Solution to Cool Your Grow Lights and Grow Room

The solutions we’ve looked at above are a mix of complex and simple steps. While some of these solutions directly address the reduction of the heat from the grow lights, others aim to reduce the room temperature so that the heat from the grow lights will no longer be as much of an issue in your grow tent or room.

The ideal solution for your grow room will depend on some factors. These include:

  • The Grow Room type is an essential factor that will influence your decision. You will require a different solution for an open grow room versus a closed room. The same also applies to a commercial grow room versus a private one. That’s why it’s important to consider the type of grow room you have when choosing the appropriate cooling solution.
  • Size of Grow Room – Another critical factor that will affect your choice is the size of your grow room. Massive commercial grow rooms will require more complex and comprehensive solutions than a smaller amateur set up.
  • Budget – This is easily the single most crucial factor determining the choice of a grow room cooling solution. How much you can spend, regardless of the type and size of the grow room, will dictate the type of cooling solutions at your disposal.

Closing Thoughts

We’ve taken the time to look at ways you can cool your grow lights and grow room. The solutions we have looked at are wide and varied, ranging from basic to complex.

Hopefully, reading this post has helped you find one or two ideal ways to cool your grow lights.