Don’t Undersize Your Return Air Openings

A duct is a duct, right? It’s just an opening, usually covered by a decorative or utilitarian grill of some sort, that allows air to travel from a source — such as a furnace or central air conditioning system – to wherever the treated air is needed: Living areas, group-use spaces, even indoor stadiums.

Not quite.

While it’s true that certain kinds of ducts deliver air, there are also other ducts – known as return-air ducts – that collect air and return it to the system to be either re-heated or re-cooled. Just as it’s critical to have enough air moving into the treated areas, it’s just as important to have the right amount of air returning to the system.

The presence of even one under-sized air return opening often means that there are other under-sized openings throughout the structure. Some experts say that undersized openings, when modified to a correct size, can improve airflow by as much as the increase in size: Doubling the opening, in other words, can double the amount of airflow.

Air return problems can even happen at the door to your utility room, which in most cases should be vented to allow enough fresh air to power the machinery. This is an easier concept to grasp when discussing hating systems, as it is common knowledge that fires burn better when there is ample access to oxygen. It’s just as important, however, to maintain adequate airflow when the central A/C unit is in use. Local building inspectors typically will not sign off on HVAC installations if the return ducts are not adequate – which includes any venting that brings fresh air into the utility room.

Consumers also need to ensure that door undercuts allow for proper air flow. If a door to a room is shut, for example, and there is not enough space under the door for air to move, the system may have significant problems cooling the room. To see this for yourself, try running your air conditioning system for about ten minutes with the door shut. Then, open the door, even just slightly, and observe what happens.

When installing or upgrading any air conditioning system, it pays to have an expert inspect your ducts, including those for return air, to ensure that you get the most out of your cooling improvements. Give AC World a call today!