I have the heat tape and fan plugged into a power strip, which is then plugged into one Herpstat outlet. That way, the fan is on when the heat tape is one, and vice versa. I mainly found that this helped in warmer months when my house gets hot during the day and the heat tape isn't needing to turn on much at all.
That's a good idea. I'll pick up another power strip and try this out as well.