Is your air conditioner not blowing air very hard? Is one room in your house hotter or cooler than the rest? You are not alone.

If you’ve noticed that some of the rooms in your home cool far more easily than others, chances are good that you’ve blamed it on a sub-par central air conditioner or your aging home. However, there’s a very good chance that it may all be tied to air distribution in your duct system.

Examining the Cause of Imbalanced Cooling

If it seems that some rooms in your home are just not cooling as well as others, many different things could be to blame. They include:

• Improper positioning of the air handler, meaning that the cooled air must travel too great a distance from the blower to the outlet;
• An HVAC system that is too small for the area being cooled;
• A blower motor that is not powerful enough to deliver the cooled air to all areas of the home;
• Air supply outlet placement;
• Closed or partially closed registers in the warmer rooms;
• Improper damper positioning, which means that dampers are not positioned in a manner that promotes balanced airflow; and
• Incorrect duct design, which includes ducts that are too long, ducts that have too many “branches”, or ducts that are not the correct size for the spaces to which they deliver air.

All of these issues can be remedied. Air handlers can be moved to new locations. Dampers and registers can be opened and/or adjusted to allow for proper air flow, and ducts can be changed and rerouted. If necessary, the HVAC system can be completely replaced, though right sizing is very important in this case.

Right Sizing is More than Just Choosing the Size of the Unit

If you’ve ever replaced your HVAC unit or chosen an HVAC unit to suit a new build, then you may be familiar with the term “right sizing”. You might think that this simply refers to the process of choosing the air conditioner that “fits” your home in terms of square footage, but there’s far more to it than that. Right sizing also includes the positioning of the air handler in relation to the rooms throughout the home. The way the ducts are designed and arranged is also important to right sizing.

Handling Air Distribution through Design

When it comes to designing the layout and size of ducts for proper air distribution, there are some steps you can follow to make sure your design allows enough cool air to reach each area of the home.

• Step 1: Choose the location of the return air duct on the floor plan. This is very important. If the return air duct pulls in air that has just come out of a register, this impacts the efficiency of the HVAC unit as a whole. It means that the warmest air in the home is not being pulled through the air handler, which causes cooling challenges.
• Step 2: Choose the right number, type, and size of air outlets. A large room often needs more than one large register, whereas a smaller room might need only one very small register.
• Step 3: Determine the duct layout. Knowing where your ducts will run in relation to the air handler is crucial to delivering just the right amount of cooled air. The farther the air outlet is from the air handler, the harder the air handler has to work to deliver that air to that outlet – and vice versa. What’s more, air outlets closer to the air handler will deliver air that is much cooler since the air travels a shorter distance and has less time to accumulate heat.
• Step 4: Choose the right duct size. Not all of the ducts in your home need to be the same size, and choosing a duct that is too large or too small for a particular branch or room will impact the system’s ability to deliver just the right amount of cooled air. Choosing the right size duct is also important for the pressure of the air. If the duct is too small, the air will be under a great deal of pressure, which can impact its temperature and cause uncomfortable drafts.

Proper Placement of Air Supply Outlets

The air supply outlet in a room is the point at which a register will be installed and where the cooled air is forced into the room. If the register is not placed carefully, it can impact the temperature of the room’s living space. When it comes to determining the proper placement, it’s important to remember that the space in which you will “feel” the temperature is two feet off the walls and six feet above the floors. This will allow cooled air to properly settle, but it will also help reduce the way people in these spaces perceive drafts, which can feel too cold and uncomfortable. As such, the air supply must be placed in such a way that it mixes the cooled air with the existing air in the room with precision.

If some rooms in your home feel warm, even when others feel comfortable, it may not have anything to do with your air conditioner itself. In fact, it may all come down to the placement and size of your ducts as well as the placement of air supply outlets throughout the home. Although it’s easier to address these issues with a new build, it is possible to relocate the air handler, reroute ducts, and reposition air supply outlets in existing structures, too.