How to Measure Floor Registers

If your home has a downflow furnace, meaning the ducts are below the floor, you have floor registers or vents that may need to be replaced over time. Floor registers may be damaged by foot traffic, moving furniture, or accidental impact. They may become rusted or corroded, especially in humid regions. Or you may simply be looking for an aesthetic upgrade. Whatever the reason, it's important to know how to accurately measure so your replacement register fits the opening snugly and allows sufficient airflow. 

We often hear from customers that the register being replaced is "standard." The truth is, there really are no "standard" registers. However, there are four most common sizes that cover the majority of applications:

• 4 x 10"
• 4 x 8"
• 4 x 12"
• 6 x 6"

How do you make sure you've got the right size for your home? 

Method 1: Measure the Rough Opening

The rough opening of the duct is the hole in the floor where the vent will be installed. Remove the current vent and carefully measure the width and length of the hole to identify the right floor register for you.

Method 2: Measure the Back of the Register

This method also requires removing the current register. It's a common mistake to measure the top of the register - remember that the top includes a lip that goes on top of the floor and holds the unit in place, so using that as your measurement will result in a register that is too big for the opening. The photo below shows a correct measurement of width for a 4 x 10" register.

As shown below, measuring the top of the same 4 x 10" unit results in a measurement greater than 4 x 10":

Summary

Floor registers are an important but often forgotten part of your home's comfort. Check registers periodically for airflow and corrosion. Also remember that in homes with pets or children, registers can be a common spot for hair or small toys to collect. If you're ready to update, we offer floor registers in white, brown, and a range of sizes.