Air Tightness Testing

Everything you need to know and how we can help
iATS approved air tightness tester
We are registered with iATS, the Independent Airtightness Testing Scheme, and have over 8 years’ experience testing. Based in Welshpool, Mid Wales, we can test domestic and commercial buildings up to Passive House levels within the Powys, Shropshire, Cheshire and Herefordshire area.

“Our lengthy experience in building low energy and Passive House dwellings means we have a wealth of knowledge in air tightness and recommended materials and their application.”

iATS approved air tightness tester

Rich is our Level 1 Qualified Air Tightness Tester. We undertake air tightness tests using our Minneapolis blower door kit which is calibrated annually to UKAS standards and we are externally audited every year, in line with requirements set out by ATTMA.

See below for what the test involves.

What is an air tightness test?

An air tightness test assesses the building for ‘air permeability’ by measuring air leakage through unwanted gaps, cracks, and holes.

More air leakage = more heat loss = higher fuel demand.

More sizeable gaps in the fabric can lead to draughts and discomfort as well as potential health issues.

Get In Touch For An Air Test Quote

Let us know the size, location of the building and build type. If you have any plans please send us a copy, they are helpful but not essential.
Free Quote

Why do I need an air tightness test?

All new buildings require an air tightness test as stated in the Building Regulations ADL1A (Dwellings) & L2A (Buildings other than dwellings) Conservation of Fuel and Power 2006. SAP (Standard Assessment Procedures) calcs also require an air test score to accurately calculate the buildings Energy Performance Certificate (EPC).

The lower the air test result, the better the EPC.

You can choose not to have an air test, but will be penalised by being given a default score of 15m³/(h.m²)@50 Pa – which is 50% higher than the worst acceptable Building Regulations standard.

What do I need to do before an air test?

The following needs to be completed before undertaking the test:

The building fabric complete


Water in all traps


Service penetrations made and sealed


Sockets fitted to the walls


Loft hatches fitted


All downlighters fitted and 240v power connected

Air Tightness Testing Cost

How many tests will I need?

When testing to Building Regs standards, one test will be required.

When testing to Passive House Standards then 2 or 3 tests are required, see below for more details.

Testing to Passive House Standards

Only once the first test achieves the desired result (under 0.6ach@50Pa) can work continue and first fix begin, and the air tightness layer can be closed off.

Arrange this to be carried out once the air tightness layer is completely sealed, but still exposed.

During the test waste pipes, MVHR inlet and outlets will be sealed off.

Carried out after the first fix stage of the project.

To be carried out once the building is complete, certification is issued upon passing.

This test should really be a formality, as a great deal of attention will have been spent on ensuring the integrity of the air tightness layer throughout the duration of the build process.

Plan Ahead – design and specify for a high quality airtight build

Start thinking about the air tightness of your project at the early stages of design. Quality now will save time, money and improve thermal comfort.
“We have used quality pro clima membranes and tape systems on our timber framed developments for many years.”

Fitting Stage

The pro clima tapes and membranes should be fitted and applied to a high standard.

Seal all penetrations and holes when the airtight layer is still exposed, so that they are sealed for the long term, and not sealed badly using products that won’t remain airtight long term. Using the likes of expanding foam on site to close off unwanted holes highlighted during the test is bad practice.

View our range of pro clima products.

They have a range of BBA approved and Passive House Certified components.
Click Here

Get In Touch For An Air Test Quote

Let us know the size, location of the building and build type. If you have any plans please send us a copy, they are helpful but not essential.

Free Quote