Nothing special, just 1,500 watt, 2 speed ones I picked up at WalMart. $18 each. I run them on a timer so they only come on during lights out. When the lights are on the heat from my LEDs is sufficient to keep the temps within range as long as I run that variable speed controller.
Is the hot air being blown out of it dry out your plants?? Or do you face them towards the bottom of your pot to keep just the soil warm?