# What size should my ductwork be?

## What size should my ductwork be?

The size of your duct work depends not just on the size of your entire house but also on the size of each individual room. Thus, one needs to gauge the square footage of the entire house as well as that of all the different rooms in order to decide duct work sizing.

### How many CFM does a 6 inch duct?

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

Duct Size (Inches) | Metal Duct Airflow (CFM) |
---|---|

5 inches | 50 CFM |

6 inches | 85 CFM |

7 inches | 125 CFM |

8 inches | 180 CFM |

**How do you calculate square duct?**

How to Calculate Round Duct Area to Square Feet

- Measure the diameter of the round duct across its widest point.
- Divide the diameter by 2 to get the radius of the duct.
- Multiply the radius by itself to get the square of the radius.
- Multiply the square of the radius by 3.14 to get the area of the duct in square inches.

**How do you calculate the size of a duct?**

Sizing Ducts. Sizes of ducts are then given by the continuity equation like: A = q / v (1) where. A = duct cross sectional area (m 2) q = air flow rate (m 3 /s) v= air speed (m/s) Alternatively in Imperial units . A i = 144 q i / v i (1b) where. A = duct cross sectional area (sq.in.)

## What are the default air flow and friction values for ducts?

The default values are for air flow 400 cfm (680 m 3/h), duct size 8 in (200 mm) and friction loss 0.28 inH2O/100ft (2.3 Pa/m).

### Is your duct size affecting your HVAC system?

Ducts that are small in size make your HVAC system work harder to keep your home at the desired temperature. If your duct size is big, the velocity of air gets compromised. It means you will not be able to feel the air flowing through the air vents.

**What size air ducts do I need for my home?**

Your best option is to use an online calculator for figuring out the duct size for your home. Ideally, every room which is 100 square feet or less needs at least one vent and two or three vents for a room size bigger than that. Even professionals use online calculators or programmed calculators to figure out the duct size.