I am converting an electric hest system to a FAG system. I have had a few companies come by and all their products are "the best" I need an unbiased opinion on furnaces/ central air units. I have had Trane, Bryant, Keeprite, Gibson and Carrier all tell me that they are the best... any info would be great. Also, does there have to be a cold air return in every bedroom or is thet over-kill?