I had a 'pro' install 2 new hvac systems for me a couple of days ago and I am unsure of his work. First off, he quoted me a Armstrong unit and I got a Concord. Are these comparable units? Second can you tell the size from the model number? Model= CG80TB075D12A-1A. Finally, I really don't feel much air movement from the vents; however, when I go up in the attic to look at the unit, I feel quiet a bit of cool air coming from the seam between the air handler and the coil. Is this normal? Thanks in advance.