Essential calculations you need to know for HVAC Ducting work

10th May 2022

Essential calculations you need to know for HVAC Ducting work

Having the correct size of each component of your Heating, Ventilation and Air Conditioning (HVAC) Systems is crucial, and contrary to what some may believe, bigger does not always mean better or more effective. We break down the important calculations that need to take place when choosing and installing Ducting, so that every HVAC engineer from trainee to seasoned professional knows exactly what to do.

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Why is Ducting size important?

The right size Ducting is just as important as having the right size components for your entire system.

Components of HVAC Systems that are incompatible in size can cause unnecessary pressure and possible failure of the entire system. That is why it is important to be aware of all considerations and calculations that must be performed, resulting in a system that will run properly and consistently.

Square footage

The square footage of the building you are looking to install Ducting in to is vital to ensuring that the HVAC system is powerful enough to be sufficient for the whole building, but not so powerful that it causes strain.

A common misconception when it comes to square footage is that many think just knowing the measurements of the entire building is all that you will need. However, calculating the square footage of the entire building is only half of the job. To get a truly accurate indication of what size Ducting will be needed, the square footage of every room must be calculated.

Friction Loss Rate

Another calculation that will need to be made is Friction Loss Rate, otherwise known as Head Loss Rate. This is important to maintain the air flow and understand the static pressure of a HVAC system.

Friction Loss Rate is dependent on a number of factors, including:

·         The number of coils

·         Length of each duct

·         The number of filters

·         The number of dampers

·         The number of grills

·         The number of registers

The equation to calculate Friction Loss Rate is very complex, so it requires a certain level of training and expertise to be able to calculate.

Cubic Feet Per Minute (CFM)

Before the size of Ducting can be determined, the CFM of each room must be measured. This is due to the fact that the level of velocity of air needs to be calculated, and this calculation is proportionate to the size of Ducting required, figuring out the CFM is crucial in making the choice of which Ducting to choose.

When a home or business has a HVAC system that is perfectly sized and in proportion, it results in a comfortable environment for all. Therefore, it is important that all factors must be considered and any HVAC engineer is aware of these factors. You can find out more about our expansive range of Ducting products here.