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Dont Do Stupid Things
Vapour Barriers
18 April 2020

John Herbert, hong kong energy saving expert, BEAM expert
John Herbert

A new air conditioning building (2020) with interior vapour barrier** is stupid!

Why? The external vapour pressure is significantly higher than the interior vapour pressure inside the air conditioning space, moisture will flow outside to inside, towards the room. the vapour pressure varies with temperature, because the quantity of water increases with temperature.

However, any internal vapour barrier will trap and cause accumulation of moisture, that will saturate the thermal insulation with water, destroying its thermal insulating properties, and increasing the building energy consumption.

How to Avoid Mould in Air conditioned Buildings - presentation on slideshare

** the term Vapour Retarder is the modern, more accurate replacement for the older term vapour barrier

About the Author

John Herbert is a veteran chief engineer with more than 30 years international engineering experience, educated in the United Kingdom, he has worked in the United Kingdom and then across Asia for more than two decades engaged by international and local companies. He is a Hong Kong Registered Energy Assessor (REA), a BEAM Professional, and stationed in Hong Kong.


tags: air conditioned building, vapour barriers, vapour retarder, vpaor barrier, moisture, damp, Hong Kong, design, architects, energy consumption

date: 15-04-21
kelcroft consultants hong kong