The Wonderful World of Vent Cover Shapes

Have you noticed that there are different register shapes? Ever wondered if you could switch to a different shape? Read on to find out about all things vent cover shapes.  

Is choosing a vent cover shape an option?  

The shape of a vent cover is likely a reflection of the shape of the ductwork behind it. The best heating and air conditioning air flow will match the vent cover shape to the ducting shape.  

There are three shapes of ductwork: round, rectangular, and oval. The shape used in your home or building was determined by the space you had available, the age of your structure, compatibility, and efficiency factors. Let’s take a closer look at each. 


Saving Space 

Square and rectangular ducting is the easiest to install and fits into a structure’s architecture far better than other shapes. It is one of the most popular shapes for ductwork today.  

If space is at a premium, oval is another option. Its lower profile means less real estate vertically, which makes a big difference. 


Older home with unusual sized vent covers. 

Age Considerations 

The type of ductwork in a structure may be entirely a question of when it was built and what was available at the time. Many older buildings have large square or round ducting and vent covers. Sometimes a particular shape of ducting and vent covers is chosen to look like it came from a different era.  



Some duct shapes are more compatible with some HVAC systems than others. The shape could be selected to optimize the connection between the underlying duct system and the heating or cooling unit.  


Close up of a round vent cover in a square pattern.
Round vent covers available to order by phone. COMING SOON to for online ordering!



Round ducting is the most efficient for moving air with less heat/cool loss and without airflow loss. Round and oval ducting requires less metal for construction and is a more efficient use of steel resources.  

Consider using louvers and dampers to control airflow for even better efficiency. 


Vent Cover Shapes 

It isn’t necessary to replicate the shape of the ductwork in the vent cover, but it is the ideal set up. Oval ducting can easily be paired with rectangular vent covers. There are also many duct pieces that convert one shape to another, such as a duct that transitions from round to square, or pieces that reduce a large circle to a smaller circle.  

While it’s important to match your vent cover shape to your duct shape, it’s even more important to get the right size. Our vent covers come in a variety of standard sizes, but you can also order custom sizes.  


Custom Sizes


Square and rectangular vent covers in a variety of colors laying on a gray surface. 

Rectangular & Square 

Standard registers available in various sizes, six colors, and dozens of patterns. Mounting holes optional. 


Round vent covers in various colors on a white background. 


8, 10, or 12 inch sizes in six colors and one pattern. Comes with mounting holes. 


Close up of a baseboard heater vent cover in a Scroll pattern. 

Baseboard Vents 

4.75 x 15, 18 or 24 inches iwth angled construction to point airflow out into the room. Available in Black, Scroll pattern. 


High velocity vent covers in gold with Reggio logo. 

High Velocity – Round 

One size available in 9 colors. Can be an open vent or have a grille. 

Shop Vent Shapes

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