Just got a townhouse with a new AC/ Furnace (duncan) in the basement. This heats 3 floors. The basement has all ducts closed and is still the warmest floor. The heat is barely reaching the third floor is will be 10-15 degrees colder than the basement. Is there anything that can be added to correct this? Different blower blade or motor? It is almost like the air isnt getting pushed to the top floor.. Anything made that can help draw air to the 3rd floor?