## What size duct is needed for 2000 CFM?

Rectangular equivalent diameter for air flows between 100 – 50000 cfm.

Air flow – q – (Cubic Feet per Minute, cfm) (m3/s) | Rectangular Duct Sizes (inches) (mm) x (mm) |
---|---|

1700 (0.77) | 10 x 22 14 x 15 |

1900 (0.86) | 12 x 19 14 x 16 |

2000 (0.9) | 10 x 25 12 x 20 15 x 16 |

2500 (1.13) | 14 x 20 15 x 18 |

**What size duct do I need for 6000 CFM?**

USING THE CFM/FPM CHART:

Air Volume in Ducts in Cubic Feet per Minute (CFM) | ||
---|---|---|

2000 | 6000 | |

6 | 395 | 1180 |

7 | 535 | 1605 |

8 | 700 | 2095 |

### What size duct do I need for 1200 CFM?

10”

At 600 CFM, the minimum duct size is 6”. At 900 CFM, the minimum duct size is 8”. Finally, at 1200 CFM and above, consider a 10” diameter duct or larger.

**What size should my return air duct be?**

Generally, if you are using a Duct Sizing Chart or calculator (such as the Trane Ductulator), size the re- turn ducts for 0.05 inches/100 ft (0.40 Pa/m) based on the expected airflow through that return air duct. The total sum of air from all the returns should be at least 250 CFM/nominal ton (33 l/s per-kW).

#### Is it better to undersize or oversize ductwork?

Proper sizing. All the ducts must be sized to match the HVAC equipment capacity. Using oversized ducts will erode the system’s efficiency, while undersized ducts won’t carry the necessary volume of air.

**Can ducts be too large?**

The Ducts Are Too Large Not much. This is what happens when your air ducts are too big for your system. Your system pushes air into the ducts, but the ducts are too large for it to build up any sustained amount of air pressure, and thus a “forced air” system doesn’t have any force.

## Can you have too much return air?

Can an air return be too big? No, an air return cannot be too big, except in extreme cases where a closed room is temporarily under negative air pressure. Return vents maintain air pressure, filter out debris, and are critical to the efficient operation of any HVAC system.

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

CFM calculation requires the size of your HVAC unit in tons to be multiplied by 400 (the average output of an HVAC unit). The total must then be divided by the square footage of your house. The air flow from your system also depends on the rate of friction loss of ducts. 2000 cfm (0.94 m3/s) of air flows through a 10 x 12 inches rectangular duct.

### How do you calculate CFM for ductwork?

0.13 ACH per square foot at ACH = 1.

**How do you calculate duct size?**

Measure the square footage of each room in the house. This is done by multiplying the width by the length.

#### How to calculate residential duct size?

Velocity reduction method: (Residential or small commercial installations)