You are using an outdated browser version not supported by this website.
Click here to upgrade your browser


Lowering the Pressure of H1 Energy Efficiency Changes with Ventüer Ventilation Louvres

Misunderstanding the pressure drop of a ventilation louvre, or using “free area” values to size louvre panels, can result in ventilation systems that are noisy, inefficient or simply don’t provide the required airflow rates. At worst, it can cause a project to fall foul of the Building Code. This is especially true following the changes contained within the H1 Energy Efficiency Verification Method H1/VM3.

Louvre pressure drop (or pressure loss) must be one of the key design considerations when selecting and sizing ventilation louvres. The pressure drop itself is the pressure differential from one side of the louvre to the opposite side. This is usually expressed in Pascals (Pa) and occurs when frictional forces, caused by the resistance to flow, act on the air flowing through the open area of the louvre.

Knowing the actual pressure loss of a ventilation louvre allows us to accurately estimate how much air will pass through it based on a given fan performance, or — in the case of natural ventilation systems — at a given wind speed.

A common misconception is the assumption the greater the free area (also known as open area), the more air moves through. This is not always the case however, and you can learn more about the science and correlation between louvre free area and pressure loss on the Ventüer website website here.

This is why the H1 Energy Efficiency Verification Method H1/VM3 purposefully expresses the requirements for louvre pressure drop in Pascals as follows:

a) Single stage louvres - 30 Pa
b) Two stage louvres - 60 Pa
c) Acoustic louvres - 50 Pa
d) Other non-weatherproof louvres - 30 Pa

The only way to be sure of meeting the new regulations is to seek information on the louvre based on test results from testing against BS/EN:13030 or AS/NZS 4740:2000. This standard sets out the guidelines for testing and classification of all weather and performance louvres, including certification of the pressure loss across a broad spectrum of airflow rates for both intake and exhaust flow directions.

All Ventüer ventilation louvres are fully tested to BS/EN:13030, and the data is presented in an easy-to-use calculator publicly available on our website. Copies of the test reports are also available upon request.

Many of the Ventüer louvres, particularly the high-performing multi-stage systems, have significantly lower pressure loss than other products available to the NZ market. This is thanks to a rigorous product development process, which uses CFD modelling and simulations to fine-tune the louvre blade profiles and details before the dies are cut and the aluminium sections extruded.

A louvre system with a certified low pressure loss comes with three advantages over a non-tested system or system with high pressure loss.

1) Compliance with H1/VM3 is easily demonstrated.
2) There is reduced load on the HVAC system and fans, increasing energy efficiency and lowering noise levels.
3) The louvre panels can be made smaller, thus being less visibly obtrusive and offering greater flexibility in positioning on the facade.

Still Confused?

The team at Ventüer appreciate that there is a lot to take in when it comes to the subject of louvre pressure loss, and you may have read through this article and still not consider yourself an expert on the topic!

Never fear — Ventüer are here to help. If you would like assistance with ventilation louvre selection, sizing or compliance demonstration, please feel free to reach out at [email protected] or (09) 973 3616.

View more information on Ventüer, including contact details.
comments powered by Disqus
February 2023 EBOSSNOW Product News

News from Ventüer

Is 5% the Magic Number?
Doubling Down on Education Standards
Naturally Cost-Effective Ventilation
Get a free weekly digest of essential news

New and updated architectural products, design solutions, inspiration, technical advice and more when you sign up for EBOSS.