VRF systems are very similar to the traditional rooftop air conditioning units with even more challenges for an indoor grow climate environment.

VRF is a comfort cooling engineered solution. They are designed for offices, hotels, etc. and are installed and sized to handle the cooling load only. Like rooftops, they will remove a small portion of the necessary room moisture during the lights-on grow mode.

There will be a high number of VRF cassettes (The ceiling boxes with vents and fans) in the space delivering cold air to help offset the temperature load of the lights.


Dehumidifiers help with the work of the air conditioner in the lights-on mode. The portable dehumidifiers have a very large job that often gets missed as humidity levels are critical.


In lights-off mode, portable dehumidifier(s) are still used to remove the moisture.  The problem is the same as challenger 1 when the portable dehumidifiers are in operation, the air temperature leaving those units are 25°F warmer than the air entering. This causes the VRF air conditioners to turn on and try to remove that excess heat and then quickly turn off again when their task has been completed.


Frequent on/off of a VRF outdoor unit causes the expensive compressors within those units to break much sooner. The grower ends up with the same problems, this system causes massive temperature and humidity swings within your grow room space. Your plants will be susceptible to browning, mold, and a much smaller post-harvest yield than a finely controlled space. This is a huge headache for someone trying to grow profitable medical-grade Cannabis.

Pros and cons of VRF units with portable dehumidifiers in the grow space:


  • Marginally lower utility bills than rooftop units
  • “Off the shelf” equipment


  • No precise temperature/humidity control (units constantly fighting each other)
  • Very high utility bills compared to our premium options
  • Comfort cooling solution for people, not plants
  • Odor control and biological-contamination challenges
  • Lots of units delivering cold air onto the plants will cause condensation to form on the leaf, which can lead to mold
  • VERY HIGH levels of refrigerant being pumped around the space, which is extremely unhealthy if there is a leak
  • Lots of compressors and fans between the VRF systems and the portable dehumidifiers. This means there are even more failure points and expensive repairs to consider.
  • No trending data or ability to link everything together for a precise understanding of the space conditions
  • Changing the temperature in the VRF system will mean the dehumidifiers won’t operate the same and you’ll have to go adjust each one.

For more information read the blog, “The Ultimate Indoor Grow Room Climate Control Showdown

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