Airtightness plays a major role in the performance of modern energy efficient homes. Even small gaps in the building fabric can allow warm air to escape and cold air to enter.
This uncontrolled air movement increases heating demand and can reduce comfort inside the building.
What Airtightness Means
Airtightness refers to how well a building prevents unwanted air leakage.
In older homes, air can escape through gaps around windows, electrical outlets, loft hatches, and structural joints.
While this leakage might seem minor, the combined effect can significantly increase energy loss.
Why Airtightness Matters
When air leaks out of a building, heat goes with it.
This means heating systems must work harder to maintain comfortable temperatures.
Poor airtightness can also cause draughts, uneven temperatures, and condensation problems.
By reducing air leakage, buildings become more efficient and comfortable.
How Airtightness Is Achieved
Modern construction uses a range of materials and techniques to create an airtight layer.
These may include:
• airtight membranes
• specialist sealing tapes
• airtight window installation systems
• careful sealing around service penetrations
The goal is to create a continuous barrier that stops uncontrolled air movement.
Airtightness Testing
A blower door test is often used to measure how airtight a building is.
During the test, a fan is used to pressurise the building while sensors measure how much air leaks through the structure.
This allows builders to identify and fix any areas where air is escaping.
Achieving good airtightness is essential for buildings designed to meet high energy efficiency standards.
