# Ductulator

Easily calculate duct sizes, pressure drops and velocities with our free online Ductulator.

Get accurate results with this simple, yet powerful tool.

## h2x for Ductulator Calculations

• Calculate the pressure drop through every duct (CIBSE-verified)
• Calculate the velocity through every duct (CIBSE-verified)
• Size all of the duct based on your design layout

h2x is CIBSE-verified design software built to improve the efficiency and quality of your design process. Read more.

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Variables:

## Factors Affecting Ductulator

Flow Rate

Determining the flow rate is crucial in duct sizing as it dictates the volume of air that moves through the system per unit of time, ultimately impacting comfort and efficiency.

Duct Details

The duct roughness and duct length (duct l) will result in a higher pressure drop, while the opposite will result in a lower pressure drop.

## Ductulator Formula

As the calculation can be measured in terms of ft/second and m/second, there are four different calculation methods to establish pressure drop and velocity:

### Pressure Drop Equation:

#### Imperial Equation

The following formula can be used to calculate the pressure drop:

Hf = f L v2/ 2gD

#### Components

• = Head loss in a duct (ft)
• = Duct length (ft)
• = Velocity of the air flow rate inside the duct (ft/second)
• = Internal duct diameter (ft)
• = Duct roughness / Duct friction factor {f = [1.14 + 2 log10(D/e)]-2} and then iteratively f = {-2*log10[((e/D)/3.7)+(2.51/(Re*(f1/2))]}-2
• = Gravity (ft/second2) , which has a constant value of approximately 32.2 ft/s2.

#### Metric Equation

The following formula can be used to calculate the pressure drop:

Hf = f L v²/ 2gD

Components

• = Head loss in a duct (m)
• = Duct length (m)
• = Velocity of the air flow rate inside the duct (m/second)
• = Internal duct diameter (m)
• = Duct roughness / Duct friction factor {f = [1.14 + 2 log10(D/e)]-2} and then iteratively f = {-2*log10[((e/D)/3.7)+(2.51/(Re*(f1/2))]}-2
• = Gravity (m/second2) , which has a constant value of approximately 9.8 m/s2.

### Velocity Equation:

#### Imperial Formula

Following the equation below, you can calculate the air duct velocity:

V = 0.408 Q/D2

#### Components

• = Air velocity inside the duct (feet/s)
• = Air flow rate inside the duct (GPM)
• = Diameter of duct (inches)

#### Metric Formula

Following the equation below, you can calculate the air duct velocity:

V = 1.274 Q/D2

#### Components

• = Air velocity inside the duct (m/s)
• = Air flow rate inside the duct (m³/s)
• = Diameter of duct (m)

## What is the Ductulator Used For and Why is it Important?

The Ductulator is a vital tool in the HVAC industry, used to accurately size ducts in heating, ventilation, and air conditioning systems. Therefore, by inputting parameters like airflow rate, duct shape, velocity, and friction loss, it helps determine the optimal dimensions for round and rectangular ducts, ensuring they can handle the required air volume efficiently.

Proper duct sizing is equally important to maintaining the system's performance, as it directly impacts air velocity and pressure drop. Hence, incorrect sizing can lead to increased energy consumption, uneven temperature distribution, and noise. Moreover, the Ductulator allows professionals to optimise duct design, ensuring smooth airflow, reduced pressure drops, and overall system efficiency.

In addition to enhancing system performance, the Ductulator ensures compliance with industry standards and building codes, which often require precise calculations for airflow, velocity, and pressure drop. Consequently, this makes it an indispensable tool for HVAC professionals committed to delivering high-quality, efficient, and code-compliant systems.

## Why Use a Ductulator?

Evidently, there are several benefits of using an online Ductulator to calculate duct sizes, including:

Increased Accuracy:

Determine accurate values by eliminating the possibility of human error when calculating air pressure drop by hand.

Time-Saving:

Saves time by providing quick and easy calculations, putting an end to performing complex mathematical calcs manually.

Easy to Use:

User-friendly and requires no special training or technical knowledge. Just provide the input and read the results.

Cost-Effective:

Can save money by reducing the number of time spent on manual and long calculations, and avoiding costly mistakes.

FAQs

### Resources

#### Webinar: Duct Sizing

Futhermore, check out the unveiling of h2x software's latest Duct Sizing feature on Mechanical Ventilation.

#### Calculate Duct Size

Find out how to calculate duct size effectively with h2x's comprehensive guide. Optimise airflow and efficiency.

#### Free MVHR eBook

What's more, explore the intricacies of Mechanical Ventilation with Heat Recovery (MVHR) in our free eBook.

## See what h2x can do

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