h2x Tools
Duct Size Calculator
Calculate ductwork accurately and easily using our free Duct Size Calculator to ensure the correct velocity and pressure drop.
Get accurate results with this simple, yet powerful tool.
Circular Duct Size:
Rectangular Duct Size:
Square Duct Size:
h2x for Duct Size Calculations
- Calculate the flow rate for every duct (CIBSE-verified)
- Design to different velocities for various air systems (CIBSE-verified)
- Automates all of the duct and fan sizing 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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Easily gauge airflow speed in ductwork for efficient air distribution by calculating air duct velocity quickly and easily.
Choose from a range of international standards, add fixtures, and automatically receive the peak flow rate calculation.
Identify insulation needs and enhance thermal performance by accurately calculating the heat loss of a building, room by room.
Variables:
Flow Rate and Maximum Velocity
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, impacting comfort and efficiency.
Maximum Velocity
Keeping air velocity within recommended limits is critical for efficient airflow and distribution in ductwork, minimising energy loss and noise levels.
Duct Size Formula
As the calculation can be measured in terms of feet/s and meter/s, there are two different calculation methods to establish duct size:
Imperial Equation
Following the formula below, you can calculate the duct size:
Metric Equation
Following the equation below, you can calculate the duct size:
What is the Duct Size Calculation Used For and Why is it Important?
Duct size calculation is vital in HVAC design, determining the dimensions for sufficient air flow in buildings. Equally, properly sized ducts ensure efficient air distribution, preventing issues like inadequate air flow, pressure imbalances, and excessive noise.
Although accurate duct sizing optimises system performance, it also enhances energy efficiency and minimises operating costs. Furthermore, the calculation considers air flow volume, velocity, pressure drop, and friction losses, meeting building requirements.
However, due to site restrictions, it's crucial to consider shapes like rectangular, circular, and square to ensure proper fit and functionality of the ductwork. Thus, precise duct sizing is essential for achieving optimal thermal comfort, indoor air quality, and overall system effectiveness in residential, commercial, and industrial settings.
Why Use a Duct Size Calculator?
Evidently, there are several benefits of using a online calculator to calculate Duct Size, 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.
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