There have been posts about damaged and/or restricted heat ducts. The ducts would have to be inspected between the bedroom and the furnace to rule that out.
The widows are supposed to be sealed.
If your trailer is under warranty, you should probably have a talk with a dealer about fixing these issues.
Sherm & Terry w/rescues Steve (std Poodle) & Eydie (min Schnauzer)
2015 Jay Flight 27RLS (Camped: 102 nights 2015, 90 nights 2016)
2006 Ford F350 6.0 PSD, Lariat, 4WD, CC, LB, SRW, auto., Camper pkg.