“Your central HVAC system is designed for your particular house. It is made to heat/cool the whole house with proper air return. It’s best to let it do its job without interfering with it. That is how you even things out.”
They put adjustable louvers on the vents to allow you to “interfere”. with the system.
Nothing wrong with shutting down a couple of rooms. Or do you require all doors in your house to be fully open at all times?
Well, that is the problem. The least-used area is the furnace room and the 2 adjoining rooms. We close the louvers but it still gets really cool in that area; thus, the magnetic covers in the attempt to shoot more cool air upstairs, where it gets really hot!
We keep those doors open in the hope that some of that cool air will move out into the other room.
The problem is that the main public rooms are not closable—they run into each other and are linked by an open stairway.