Upstairs Is Hot

by Matt

I bought a house with a brand new ac unit and there is not enough cold air coming to the second floor. The main floor is great but the upstairs is not.

i have closed extra vents down stairs and in the basement but it still doesn't cool down. i can feel the air coming out of the vents and it is cold, but the rooms remain hot. And in the winter they are cold, is this an insulation issue,do i need more, or something else?