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The standard unit for the rate of heat transferred is the watt

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    The standard unit for the rate of heat transferred is the watt

    If LED and HID lights are powered at the same watt, but you have the ability to air cool the HID then will that keep the grow tent cooler than hanging an LED in the tent?

    #2
    My tent is 3ftx3ft. I quote "The average LED grow light draws about 32 watts to cover 1 sq ft". 315w CMH is made for 3'x3' space. that is 35 watts per sqft. An LED @ 32 watts per sqft for the 3'x3' tent is 288watts. A difference of 27 watts which is 92.13 Btu/h. So, with that, will an air-cooled reflector remove more than 92.13 Btu/h of heat out of the grow tent?

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      #3
      This is a close call. Using an air cooled fitting means running more power to get the same light output. A sheet of glass, like any obstacle, can be 10% for finger maths. About 20% of an HIDs power leaves through convection. You can catch a bit more as hot air as radiated heat warms the alloy and glass, offering another route for your consumed power to become hot air. An insulated shade would increase how much of that you could capture. It's about here somewhere that we see air-cooled shades run out of technical ability. Nobody has bothered to go that extra mile with insulation and double glazing. The basic gain is about 20% of your heat but you loose 10% of the light. I can't remember the last time I saw them used. If we think commercially, a 10% power increase sent to refrigeration gear would offer more cooling. The best gain seems to come from leaving the fitting open, so you can get that warm air straight from the lamp. While not loosing 10% of your light.

      Your question seems to revolve around total heat loading, like you want a sealed space. In most situations, even if you match the heat input between lighting types, the result is very different. The HID will still radiate half it's power down onto your plants as heat. The LED will release heat mostly through convection currents.

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        #4
        Temperature swings:

        Lights Off:
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        Top is my room temp and #3 is inside the tent:
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        Lights On:
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        Top is my room temp and #3 is inside the tent:
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        Light is HLG QB648 Diablo Double

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          #5
          You don't like the temperature?
          It's a bit foreign to me, but seem reasonable. Like 25-30 perhaps.

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            #6
            I just wondering if LEDs are efficient with heat in a grow tent if it heats it up 10 degree F vs room temp

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