Cold air vents, also called return vents, are an integral part of many heating systems, especially various types of furnaces. The idea is to pull or suction cold air from various rooms in a building or home and bring it to the furnace to be heated. This warmed air is then redistributed through the building through the furnace vents. This system operates very efficiently by both removing the cold air and adding the warmer air. 

Location Of Air Vents

Most cold air vents will be located on or near the floor. Since warmer air rises, the coolest air in most rooms will be at the floor level. If vents are put too high, it can leave pockets of cold air down low, making it difficult to heat the room thoroughly. The hot air vents can be located at any level, although many will be on the floor as well. The hot and cold vents may even look identical, but you can tell the difference when a furnace turns on. Some vents will blow air (hot), while others suck air in (cold).  

Number Of Vents

The amount of vents in a building or home depends on the design of the system. Many homes will have both cold and hot air vents in all rooms. However, depending on the building, sometimes there are only limited numbers of cold air vents that are situated throughout, maybe only one or two per floor. 

Using cold air vents make heating systems more efficient. Removing the cold air and adding warmed air means the furnace needs less fuel for heating, saving both energy and money for the building or home owner.  If your home suffers from warm spots or cold spots, talk to your your HVAC contractor.  They can conduct a system efficiency analysis and recomment improvements to your HVAC system such as sealing leaky ductwork or installing a modern, efficient duct system.