Hi guys. I'm not there (Scarsdale,NY) but my wife says the upstairs vents are blowin hot and downstairs cool. It's so hot upstairs at nite she's opening the windows (duh?) but hey, like I siad I'm not there. Going home for Xmas and will give it all a good look and report back. Told her to close the upstairs vents and that should divert more heat downstairs. She can't, they're stuck open. Swell. Guess I'll put in new smooth working vents when I get there. It's a one zone system, about 20 years old, oil fired and combined with central AC. Any ideas why there's not equal heat from all vents? Could it be duct blockage? Appreciate any advice before I get there so I can make a more informed analysis. Cheers and best regards, Ric from the UN in Budapest.