He offers such a setup but I didn't choose it. I don't mind flipping it on/off as needed since the switch is so convenient. I don't have a heatroller for the vest either.
I got in 300 miles with temps in the 20s last weekend and another 350 yesterday with temps in the 60s. The heater works and I only needed to stop for gas and food. Not once did I need to restore feeling in my butt.