What is the free area of a duct measuring 38" x 22" with a 1' liner?

To calculate the free area of a duct, you need to consider both the dimensions of the duct and any liner that is applied. In this case, the duct measures 38 inches by 22 inches. When thinking about the liner, it's important to know that it will reduce the internal dimensions of the duct.

First, convert the measurements from inches to feet, which is essential for calculating square footage. The dimensions translate to:

• 38 inches = 38 / 12 feet = 3.167 feet

• 22 inches = 22 / 12 feet = 1.833 feet

Now, to find the area of the duct, multiply these dimensions together:

Area = Length x Width = 3.167 ft x 1.833 ft = 5.8 square feet.

However, with a 1-foot liner, we have to adjust the internal dimensions to account for the liner. The liner reduces each dimension by 1 foot.

The new dimensions will be:

• Length: 3.167 ft - 1 ft (for one side) = 2.167 ft

• Width: 1.833 ft - 1 ft (for one side) = 0.833 ft

Now calculating