I think this is the right thread so here goes... I just bought a 115,00 btu, 95% efficiency, 14 seer, variable speed Amana furnace and Amana outside central air unit. I previously had a 20 year old Lennox outside central air unit and a Goodman furnace. My problem is that the air flow coming out of my ducts is less (not cooling as well) with the new units than with the older units and the new furnace's coils are freezing up when we run our air conditioning. The XXXX Heating and Air tech told me it is freezing up because I'm closing off the duct openings in the basement (we have a two story house with a finished basement). I closed the basement vents so more air flow would reach the second floor where our bedrooms are. The model number of the furnace and blower unit is AMVC951155DXAB. My question is: Is the tech right? Would closing the basement vents cause the system to freeze up, and why isn't there strong air flow upstairs? If he is right it means that I will have a freezing basement and a hot second floor. Also shouldn't the brand new units be blowing my hair back in my bedroom? It is a 5 ton air conditioner for 2500 sq. ft. of space. I know there isn't a problem with the duct work because of the good performance of the older unit. I am at a loss after financing $XXXX and not staying cool. Sorry for the long thread and thank you for any input!