Yes. They are there to draw the air back into the furnace that blows out of your heat/cooling vents. They help create air circulation and clean the air that is "returned" to the furnace and passes thru the furnace filter.
Only the low air returns have dampers, and they should be open in winter, so they can suck in the lower cold air (cold air sinks), and in summer the dampers should be closed, so the high air returns suck the hot air near the ceiling (hot air raises)
Floors in heating season, ceilings in Air Conditioning season
Open, that`s where the cold air is.
You do not need cold air returns in every room. Normally your warm air registers are close to your outside walls, your cold air returns which are much larger are placed in the center of your house . There may be one or more cold air return depending on the size and layout of your home.
Cold air returns are typically located near the ceiling in a room because cold air is denser and heavier than warm air. Placing the returns near the ceiling allows the colder air to be efficiently drawn back into the heating system for re-circulation, helping to maintain a comfortable temperature in the room.
500
I would think both. Cold air from the room goes in the bottom and warmer air comes out the top.
Approximately 7-10% of cold air escapes from the refrigerator each time you open it. The amount of cold air loss can vary based on factors like the duration of the door being open and the efficiency of the refrigerator seal.
A cold air intake should be blocked from engine compartment heat and a large supply of outside air. Mine has the air cleaner mounted outside the engine compartment in a void inside the fender with a open bottom twice the area of the air cleaner.
chance but for and ,the air was cold and the sun was hot?
Moisture in the air condenses on the cold bottle. If the air is dry, there will be no dew on the bottle.
It depends on how cold you want the area that your using the air conditioner on.