What is airtightness and why does it matter?

air sealing system
(Image credit: AeroBarrier)

You might have heard the term, but what is airtightness? While it is often talked about when discussing eco homes, when comes to the future of our houses it can be a little confusing to understand exactly what it is and why it is important. 

Like insulation, airtightness is part of a fabric first approach to building, designed to limit reliance on space heating, creating houses that are thermally efficient at their core. Therefore, when it comes to building your own home, airtightness is an important factor. But what exactly do we mean by an airtight home? How is it measured and tested?  

Tim Pullen

Tim is an expert in sustainable building methods and energy efficiency in residential homes and writes on the subject for magazines and national newspapers. He is the author of The Sustainable Building BibleSimply Sustainable Homes and Anaerobic Digestion - Making Biogas - Making Energy: The Earthscan Expert Guide.

He formally ran energy efficiency consultancy WeatherWorks and was a speaker and expert at the Homebuilding & Renovating Shows across the country

Paul Testa

Is an architect, the director of HEM Architects and a specialist in low energy design.

Tim Pullen

Tim is an expert in sustainable building methods and energy efficiency in residential homes and writes on the subject for magazines and national newspapers. He is the author of The Sustainable Building Bible, Simply Sustainable Homes and Anaerobic Digestion - Making Biogas - Making Energy: The Earthscan Expert Guide.


His interest in renewable energy and sustainability was first inspired by visits to the Royal Festival Hall heat pump and the Edmonton heat-from-waste projects. In 1979

this initial burst of enthusiasm lead to him trying (and failing) to build a biogas digester to convert pig manure into fuel, at a Kent oast-house, his first conversion project.


Moving in 2002 to a small-holding in South Wales, providing as it did access to a wider range of natural resources, fanned his enthusiasm for sustainability. He went on to install renewable technology at the property, including biomass boiler and wind turbine.


He formally ran energy efficiency consultancy WeatherWorks and was a speaker and expert at the Homebuilding & Renovating Shows across the country.