Help & Advice > Project Guides > Roofing Ventilation

How many vent turbines you will need depends on certain factors. This includes the roof size and type of building.

Having the correct number of turbine vents provides an effective and balanced system. Furthermore, it ensures a continuous supply of air moves through the desired space.

This guide is to help you calculate how many turbine vents you need for your roofing project.

Please note: The following information is for reference only. The exact number of units required will depend on the shape and overall dimensions of the roof.

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How to calculate for turbine roof vents

Below are two calculations you will need to do. The first will focus on calculating how many turbine vents you need for your roof type. The second will be used to calculate the interior ventilation.

Calculating for common roof types

You will first need to know the surface area of the roof to calculate how many turbine vents you will need. The table below is a guide applicable to the most common roof types and pitches.

Here is a brief example:

Your roof structure has a ventilated area of 150 m2. You want to use the Lomanco BIB12 unit. In this case, you would need three units for an efficient and balanced ventilation system.

Ventilated areaIB8 ventsBIB12 ventsBIB14 vents
0–90 m2322
90–140 m2622
140–185 m2932
185–230 m21243
230–275 m21243

Calculating for the ventilation of interiors

This table is an example of how to calculate the ventilation of the interiors. This is based on m3/h. The recommended frequency of air exchange depends on the type and use of the building.

Here is a brief example:

Living rooms and offices have a recommended rate of 2-3x per hour. However, for medium-duty industrial operations, this can go up to 8-10x per hour.

Model/wind speed8 km/h13 km/h24 km/h
BIB12590 m3/h930 m3/h1,750 m3/h
BIB14710 m3/h1,200 m3/h2,250 m3/h
IB8165 m3/h295 m3/h565 m3/h
TIB12590 m3/h930 m3/h1,750 m3/h
TIB14710 m3/h1,200 m3/h2,250 m3/h

Lomanco vent turbines

Lomanco vent turbines are exclusive to Roofing Superstore. They are an eco-friendly and low-cost solution to ventilating roof space. These vent turbines also reduce the need for electricity. Something that can be expensive and noisy.

They come in a range of sizes and colours. As well as a lifetime warranty when used for residential projects. You also have a 15-year warranty when installing the vent turbine for commercial use.

Lomanco turbine vent

Need assistance working out how many turbine vents you need?

If you are unsure of the calculations above, try Lomanco’s online ventilation calculator. This will give you the correct number of roof wind turbines needed for the available space.

You can also contact our roofing experts who will be able to help you determine how many turbine vents you need.

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