I have a sixty year old home with an three year old forced hot air oil heat system. I added AC this year to the unit with a 4 ton unit. (which is way oversized) My home is small 1400 s.f. and I am having problems getting the hot air/cold air to the second floor. The duct work is in place and really cannot get altered. Is there somethng that I can add to my heating system to force more air upstairs? What options do I have?

Thank you for your assistance.

You can try shuting down the downstairs registers a little at a time to see if it will help move more heat or air to the upstairs.

If you did not allow some height for the A coil in that oil furnace it might be restricting the air flow especially if it has a drum heat exchanger.

We found over the years that on a oil furnace which most have a drum heat exchanger you have to raise the A coil about 12 to 18 inches minimum off the top of the furnace. The drum heat X does not allow the air to flow properly through the A coil and causes a major restriction. Been there done that over 40 years ago..