Why is my living room always cold?

We have the same insulation throughout the house, yet the living room is very cold. This home has an upstairs as well. We have Anderson windows double paned, and no air is getting in anywhere that I know of. I went along the walls and windows top to bottom checking for drafts, but nothing. We do have a gas fireplace, but no cold air is coming in there. We have three heating vents in that room as well and are opened. Most of our winter winds come from the other direction not hitting the living room. Am I missing something here? This is a new home.