I have had some issues with renovators, the question being, placement of the cold air return in a finished basement. What is acceptable, ceiling height or floor height, not common practice.
Opposite of supply vent.
You want the cold air coming back to the furnace if you can do it, that is near the floor or if you can’t follow what Christopher said.
Kevin I am going to pick on you if ya don’t mind and if you do mind I am going to anyway:D
The title of this thread was aimed at cold air return would someone define the word cold air why not the word warm air return In the world I worked in it was always referred to as simply return air. Where in the world would a return come back to if not the furnace do yous have a separate blower circulating air this makes no sense to me explain please
Cold air return or air return. The biggest mistake people make when it comes to the air return is putting it on the ceiling in the basement. I know it is a challenge to get the air return near the floor but this is wear the cold air resides. You want the coldest air going back to the furnace and not the heated air. If you take back the heated air you are left with the cold air still at floor level. This is why in a cold climate it is next to impossible to keep a floor warm unless it is heated or well insulated. To combat the loss of warm air many put a door to the basement at the top of the stairs. This is no good because the heat will escape up to the door. If the door is installed on the bottom of the stairs the heat is maintained in the basement area and it prevents the stack effect.
Now the opposite is needed for cooling conditions but that is a new topic for discussion.
We use the same principle in installation of a HRV, have all the warm air possible at the highest point pass across the cold air coming into the unit and extract the warm air from the exhaust. Not doing these simple tricks will make either your furnace or HRV not perform to its maximum potential.
I was just wondering why the word cold is always attached to the words return air in the home inspecting world to me its like having an elevator in a out house;-)
The same reason as using the term “hot water heater”.
Get with the program Charlie. 
I wuz about 18 years of age when I quit using the term (Hot water heater) that wuz immediately following the smack up side of my head with a pipe wrench by and old plumber
So are you suggesting putting both the supply and return at floor level at opposite ends of the room?
Cold air falls down the stairs to the basement, that’s where the return air inlet belongs, on the floor at the foot of the stairs. If you have natural draft furnace, do not have the return air inlet too close to the furnace as back drafting can result.
Agreed
It would depend on the lay out of where the stairs is and If the stairs had a door at the bottom and other considerations. Finding the coldest area for the return is best.