Should I use a 3 watt or 7 watt heating pad for a terrarium that is 12x12x12?

Question

I think the 7 watt may be too large I'm not sure. Will the 3 watt be powerful enough?

Answer 1

i'd go with 7

Answer 2

I would get the 7 watt heat pad. You should also control the pad with a  rheostat or thermostat because heat pads can heat to around 110 degrees.