We have an old rooftop Gettl (sp?) unit that died this week. The old unit has an over-under ductwork setup on the elbow into the house, with the return air duct on bottom and duct pushing air into the house on top.

There are very few over-under setup units available on the market today. If we go with a side-by-side elbow setup, they would have to use a twisted elbow to change the configuration to match our over-under ductwork in the house? Will this adversely affect the airflow and thus the efficiency since the unit has to run longer to push more air through the house?

We have had conflicting answers from the 5 dealers we've had out for bids. 2 of them did not recommend doing a twisted elbow. We definitely do not want to spend $6,000 on a new unit and have it not perform effectively.

Thanks in advance,