# How do you calculate CFM for duct size?

## How do you calculate CFM for duct size?

Cubic Feet Per Minute Size Calculations Since the size of your ductwork can increase or lower this measurement, you’ll have to find the necessary CFM for each room before you can get the right duct size for each space. Cubic Feet Per Minute = (HVAC Unit Tons x 400) / total square footage of home.

What size ductwork do I need for a 3 ton unit?

If the actual airflow is unknown, use 400 CFM for each ton of cooling. A 3-ton heat pump has approximately 1200 CFM of air flow.

### How many CFM can a 6 duct handle?

A rectangular 6×6-inch duct has an airflow of 110 CFM. Bigger 6×12-inch ducts can handle 270 CFM airflow.

How do I choose duct size?

To calculate the required equipment size, divide the HVAC load for the entire building by 12,000. One ton equals 12,000 BTUs, so if a house or office needs 24,000 BTUs, it will take a 2-ton HVAC unit.

#### How many CFM does a 10 inch round duct have?

CFM Sizing Chart For Metal Round Ducts (50-2,000 CFM)

Duct Size (Inches) Metal Duct Airflow (CFM)
7 inches 125 CFM
8 inches 180 CFM
9 inches 240 CFM
10 inches 325 CFM

What size ducts should my return air be?

The total sum of air from all the returns should be at least 250 CFM/nominal ton (33 l/s per-kW). If the duct system is installed in an unconditioned area, such as an attic or crawlspace, you should use a duct with at least an R-4.2 thermal resistance1.

## How many CFM can a 10 duct handle?

CFM Sizing Chart For Flex Round Ducts (50-1,700 CFM)

Duct Size (Inches) Flex Duct Airflow (CFM)
7 inches 110 CFM
8 inches 160 CFM
9 inches 225 CFM
10 inches 300 CFM

How many CFM can a 12 round duct handle?

CFM Sizing Chart For Metal Round Ducts (50-2,000 CFM)

Duct Size (Inches) Metal Duct Airflow (CFM)
8 inches 180 CFM
9 inches 240 CFM
10 inches 325 CFM
12 inches 525 CFM

### What do you need to know about Trane TD1 ductulator?

Includes scales for friction loss per unit length, air volume, air velocity, round duct diameter, and rectangular duct diameters. One side uses English units, the other side uses Metric units. Includes a protective sleeve with ASHRAE recommended design air velocities for system components/applications.

What kind of calculator is used for duct sizing?

Ductulator – Hand held rotating calculator used for sizing supply and return duct systems using the equal friction design method. Includes scales for friction loss per unit length, air volume, air velocity, round duct diameter, and rectangular duct diameters.

#### Is there A Trane calculator for my PC?

Click to download this program to your PC. These charts focus on the range of temperatures most suitable for comfort-cooling HVAC applications, and include the Trane coil curves, which depict the condition of the air leaving a cooling coil. Also, printed psychrometric charts are available to order.

Do You need A Trane coil curve calculator?

These charts focus on the range of temperatures most suitable for comfort-cooling HVAC applications, and include the Trane coil curves, which depict the condition of the air leaving a cooling coil. Also, printed psychrometric charts are available to order.