Yep, D terms are needed in systems where there isn't a natural dampening or reversing force that will naturally bring the value away from what your output tries

Yep, D terms are needed in systems where there isn't a natural dampening or reversing force that will naturally bring the value away from what your output tries to do. With a heater,once you get to zero error, any overshoot will reduce back the opposite way because heat is always lost.