Need to check that ducting is properly attached to furnace discharge plenum
Then need to check air flow at each register.
Find any that are low/lacking air flow...then you need to check for obstruction in duct. Could be clogged, crushed or to tight of a bend in duct.
Short of sticking a camera down thru duct.......you can disconnect duct at furnace and then use blower (wet/dry vac hose connected vac discharge, leaf blower etc.) to blow air thru duct and check air flow coming out register.
High air flow in....low/lacking air flow out......problem with duct.
New TT..........warranty issue
Is it time for your medication or mine?
2007 DODGE 3500 QC SRW 5.9L CTD In-Bed 'quiet gen'
2007 HitchHiker II 32.5 UKTG 2000W Xantex Inverter
US NAVY------USS Decatur DDG31