LEDs might emit much more energy as light compared to incandescent lights, but that light will get absorbed by plants and surrounding and will eventually end up mostly as heat, no matter what light you have. This rack has 24x18W = 432W worth of lights, which is equivalent of a small space heater running on low.
2 of those racks in a small room in the basement is enough for me to have 24C (75F) in that room while the rest of the basement is closer to 12C (45F). The fanciest of growlights may have saved me 1-2C, or not.
LEDs might emit much more energy as light compared to incandescent lights, but that light will get absorbed by plants and surrounding and will eventually end up mostly as heat, no matter what light you have. This rack has 24x18W = 432W worth of lights, which is equivalent of a small space heater running on low.
2 of those racks in a small room in the basement is enough for me to have 24C (75F) in that room while the rest of the basement is closer to 12C (45F). The fanciest of growlights may have saved me 1-2C, or not.