A. A heat pump pulls heat out of your home in the summer, just like an air conditioning system.  In the winter, the heat pump captures heat from the outside air and transfers it to your home.  (Yes, even cold air has heat energy in it.)  A blower fan then pushes this heat through your ductwork and your vents.

A. You can close some vents in unused areas of the home but be aware that your insulation is the exterior walls, if you let the room get too warm or cool you will still need to overcome that in the adjoining rooms. Closing off too many vents may also cause issues with the furnace or air conditioner.