Don't know what vehicle you have but, sounds like the duct work came apart for the middle vents.
the middle vents only supply air from the ac unit using a separate in dash fan. the floor and defrost vents come only from the heater
Yes vents can be in the floor instead of the wall.
Cold air return vents are the ones on the wall
The a/c - heater controller is out...........
The flap that directs sir to the selected vents is jammed or broken...or the switch that controls it is.
some thing is probley cloging the vents take it appart and ckeck.
Warm(er) air rises - if vents were high up there would be little circulation without fans.
The selector mechanism needs repair or the doors inside the vent are jammed.
The most likely cause would be a vacuum leak at the rear of the engine or a defective selector switch.
the vents work because of the heat which can make the hot air balloon go up
It should blow through the floor vents. Modern vehicles generally use movable baffles in there HVAC systems, to direct air flow where the controls indicate. If the controls allow airflow to the floor, but nothing flows out, there is a malfunction between the control switch and the actuator that directs the flow.
When there is a problem with the vent system it dfaults to the defrost setting. Sounds like you have a problem in the doors that direct the air flow.
Heating vents should be located near the floor since hot air rises. If the heating vents are located near the ceiling the heat would stay there and not warm the room.
Vents are uaually operated by vacuum. Chances are, you have a vacuum leak at the directional valve or at the back of the air controller itself. All of these are in or under the dash. Good luck.
No, floor vents will not help in cooling your house since they are only used when your air conditioner is on. Fans are the cheapest way to cool a home down.
This is a very common problem and you need to check for a vacuum leak, broken vacuum line or a loose vacuum line......
Forced air vents set flush in the floor? They generally just lift straight out.
Fuel level, heat or air conditioning up, both high and low, high only, floor only. Center vents are for air conditioning output only, no heat. Heat is designed to blow out side and floor vents only. NOT center. Center is only for air conditioning or summer vents.
At its most elemental, simple gravity, as colder air is heavier and from the ceiling falls through the space to the floor where it is then returned to the ac for recooling.
Because the air selector died.
Near The Floor
The sensors may be off you havento take it in to a machanic.