Appreciate all the replies I'm digesting. Ok in exchange for a burger anytime you're in suburban Philly:
6000+sqft. Windows always have been leaky - fine, I get that. Sealing helped a smidge. The following I' *don't* know if it's HVAC related, but here goes.
2 years ago - 100% new furnace and HVAC due to flood. All good. However cold air comes before it gets warm. Noticeable. Company adjusted differential - improved. NOW here's the mystery:
Basement- gets REALLY cold. As in -as cold as outside. I'll watch a game down there - just fine then all of a sudden I need 2 sweaters and a winter hat. I FEEL some breeze. Infrared toy shows cold spots - but not where the air might be coming from. When heater isn't going I feel TINY trickle from vents. - tiny - -NOT enough to freeze a 1500 sq ft basement so fast. In the basement I hung streams of toilet paper....and when the room is still, no heat flowing - I notice the toilet paper swaying a little bit. I just can't imagine where the heck the air comes from because when I. see that I check the vents - nothing.
Main level - A lot of the cold is bad windows. BUT same thing. I'll walk the foyer now - it'll be ok. But within 1 hour, wouldn't surprise me if it's really cold.
ANY ideas? Heater dude claims furnace fine though I dont think he understood problem. He says it can't be a leaking duct in basement because then we'd get no heat on main level.
This is like the Loch Ness monster. If you sat in the basement or even main level I swear, within 60 minutes - with heater set at same temp (74).....you'd go from feeling warm, to really feeling cold. Luckily I have an attached gazebo with simple baseboard heat - lol that and the outdoor pool are the two places the temp is consistent. Any ideas what this could be? I don't know where to begin.
So my 1st world problem is a 6000{sq ft home on perfect lot - $20k per year in prop taxes. And I can't even watch a movie in the basement during winter. (I hope this doesn't keep going in summer)