Is it normal for there to be a high-pitched whining sound when heater is activated. Also, it seems I have to set it at around 80-85 to keep the heat on for any significant period. Lower settings it just comes on and then goes off. Thanks for your help.

I assume that you are referring to a ducted central split system. If so, if the whining sound is coming from the return air grille that is an indication that the ducting may be undersized, or you have a restriction to flow back to the furnace or air handler, that could also contribute to the temperature setting not amtching the indoor temperature and allowing for improper run times and requiring a higher setting on the stat to allow for a long enough runt ime to stisfy the temperature setting. Check your return ducting to verify it is not collapesed or if it is insulated internally that the insulation has not come loose and is blocking the airflow. Hope this helps!

Dan