So I'm watching the HVAC guys put in a new Air Handler for our electric Heat Pump. Merry Christmas to the savings account! It includes a Variable Speed Fan and this will be the first one for me. They're telling me it's best to leave it in the ON position (instead of the AUTO) all the time. The little bit of energy it uses knowing how to push air around is less than if it were on AUTO and the heat pump had to kick on more. They say with the wood stove it will especially help to keep it ON all the time? Is that the case? I'm trying to wrap my head around the "variable" part and how it is smart enough to know which fan speed to use? Especially with heat coming from my stove and not the Heat Pump. Thoughts? Advice? Help me understand? Thanks.