can anybody tell me how the heat which comes off the spydrs compares to hps and cdm
If the entire light of any type is contained entirely (including any ballast/power supply) within the grow area, one can simply convert wattage hours to btu (3.41 btu / wh).
a Gavita Pro 1000e produces 3,614 btu per hour (1060w X 3.41)
a SPYDRx Plus produces 2,250 btu per hour (660w X 3.41)
If you place the ballast/ power supply outside the grow area, then you must separate out the watt hours consumed by that equipment (I don't have that data handy, but it's available I'm sure)