The Mysterious Cold Air Return

Word Count: 150 approx

Type: Blog Post (Ghostwriting for HVAC company blog)


You know it’s there. That mysterious vented hole that lurks in the far reaches of your rooms—quietly doing it’s very important job. But what is it’s job… exactly?

The cold air return vent is for returning air to the furnace. Contrary to popular practice, it should not be used as a wiring highway for your latest surround sound or digital experience.

If you have a forced air furnace, an exchange of air is constantly taking place inside of it. The furnace takes in cold air, heats it up and then blows it out hot through your heater vents.  The cold air return lets the furnace breathe in the air of your home, in order to allow for proper air flow. If you let dust gather or cover your cold air return vents in the winter, you’re essentially starving your furnace of it’s intake. This can create an air vacuum in your home that is uncomfortable and potentially dangerous—think carbon monoxide. (In snowy weather, it’s important to ensure that fresh air intake pipes and gas meters are free of snow and ice.)

Not only does your house need cold air return vents, but it needs an appropriate number for the proper air exchange. There is a lot of math involved. But, essentially, the return area should—at the very least—be equal to the supply area. Some folks in the industry say that for every heat vent in a room, you should have a cold air exchange of equal size to keep your furnace healthy and provide the best air flow in your home. However, in a lot of older homes, there are no cold air return vents in the bedrooms. This means no air flow, and consequently these rooms can remain stagnant and chilly in the winter.

If you want to know if you’re getting the best air flow in your home, give us a call and we can have one of our experts do the math. 🙂