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Read the latest news & industry developments



Why is air tightness important?

Hugh Franklin

3rd March 2023


Company news Eco Homes Technology

A building’s air tightness level is affected by unwanted air leaking in or escaping from gaps and cracks in its walls, floors, and ceiling – but how much can this specifically impact you and your home or commercial building?
From reducing everyday bills to looking after your health, in this blog we explore three primary reasons why air tightness is so important…

1. Saving energy and money


Between 30% -70% of all building heating and cooling is lost through draughts and is often the largest component of energy wastage in buildings, as Tom Fenton from Veritherm shows in this image below:

Tom Fenton from Veritherm, 2023
Tom Fenton from Veritherm, 2023


With the current energy crisis and ongoing Net Zero aims for the UK, homeowners and businesses like you are looking at ways to save money on energy bills in the short and long term. The Financial Times estimates £10bn per year could be saved through basic energy-saving measures – and air tightness is a critical energy saver! Reducing air leakages will reduce your energy consumption and in turn, your energy bill.

2. Creating healthy homes


The average person spends between 80-90% of their time indoors. With more people working from home than ever, this had led to the UK becoming increasingly aware of what a healthy vs. unhealthy indoor environment is.

Indoor environment quality encompasses a variety of different elements from day-to-day life. This could be simple fixes such as creating an effective ‘working from home zone’ with improved lighting and office chair vs. working off a small laptop screen at the kitchen table, to key elements such as certain rooms being overly cold, hot, damp, or musty

Controlling draughts and improving air tightness is key to creating healthy indoor environment quality – it’s the same principle as making sure insulation is consistent in a loft or across a wall. Reducing cold or draughty spots reduces the chance of condensation and moisture tracking, pest intrusion, and sounds or pollutants infiltrating through the walls of your building.

One of the most common misconceptions about creating an air tight home is that it needs to breathe – but what does that actually mean? One thing is certain: if a building is ‘breathing’ through its envelope, that doesn’t mean clean air is finding its way into and out of the structure – in fact, exactly the opposite is happening!


Joe Medosch shows how to breathe through the building enclosure


As Dr Bailes demonstrates in the image above, uncontrolled air movement through the walls draws all kinds of allergens into the indoor environment – from particulates and materials through the walls to inefficient recirculation of the internal air, a building with air leaking often means a poorer, rather than higher quality indoor environment. This is where the AeroBarrier system comes into its own, ensuring unwanted draughts are controlled and measured to a specific and tailored level. Explore how AeroBarrier works.

3. Long-term durability


By improving air tightness and reducing air leakages, the structure and fabric of a building are more resilient to decay over time and ensure the structure will be as long-lasting as possible.

Damp and mould in insulation is a key concern for modern buildings, which is often unseen due to being behind plaster and paintwork. What’s more, air leakage accounts for 98% of all moisture movement through a building’s fabric, which can have a significant impact on the dew points and movement of vapour through a building, even if it’s designed to be vapour-permeable!

For example, at Building Regulations (2013) limits for air tightness, the allowable size of leakage is around 20mm x 20mm penetration per m2 of a building’s envelope – around the same size as a 20p coin. At typical temperatures and humidity, this would mean around 100 times more moisture would be allowed into the walls, ceilings and floors than if the building was fully air tight – 30l of water per month, rather than 300ml!

What makes this even harder to detect is that air leakage in modern buildings is often a combination of lots of small, invisible areas of leakage rather than one big zone of leaks. This makes finding and sealing these areas harder.


Illustration Source: Illustration Source: CHBA Manual, Fig. 2.10, Pg. 25
Illustration Source: Illustration Source: CHBA Manual, Fig. 2.10, Pg. 25


As a solution, the AeroBarrier system identifies and seals any leaks from 12mm right down to 10 microns (the same thickness as human hair!), in a real-time and measured way. Through the pressurisation of a building and the application of a water-borne, mist-coat system, AeroBarrier guarantees that any air leakage in the building is identified and sealed in a consistent and controlled manner – allowing you to specify an air tightness level that’s specifically tailored to your project, and be confident that this will be comfortably achieved.

So, how does AeroBarrier work?


AeroBarrier will find and eliminate any unwanted building draughts in four hours and four simple steps… Here we explain and show you how.

Discover how you can achieve & exceed airtightness with AeroBarrier.

Discover how you can achieve & exceed airtightness with AeroBarrier.

Have a question? Or need a quote, get in touch with our team today.

Contact us on: 01432 513 499 or