We can help your building project achieve a PassivHaus standard 


Low Carbon Box provide competitive air tightness testing with excellent customer service



We meet the requirements set out in Building Regulations Part L1A and L2A and are ATTMA registered


If the air test fails, we will detect the leaks, allow local repairs and retest on the day!


We use UKAS Calibrated air tightness testing kit and our staff are CSCS accredited


We have flexible, competitive rates with significant discounts for multiple air tightness testing.

WHAT WE DO Steps in our work

LOW CARBON BOX are based in Leicestershire and ideally located to air test nationwide.
We recommend our air tightness testing services from early design stage to assist in achieving Building Regulation compliance and provide easy integration with a successful outcome.


Discuss your project and get advice. We also provide a checklist to help you along. We will need your drawings and SAP Calculations.


We will attend site at an agreed time and test the unit(s). If a failure occurs (see air tightness testing issues), then we will check for leaks and allow any works to be carried out and re-test within the hour.


We tell you the result on the day and email the certificates and report as soon as we get back to the office.


We are ATTMA registered air testers with fully calibrated equipment. We also hold CSCS cards for site health and safety.


We offer flexible payment terms and bulk discount for joint services (SAP, SBEM etc). We offer air tightness testing in Birmingham, Midlands, Leicester, Lincoln, Milton Keynes, Essex, Tamworth, Hinckley, Northampton, Nottingham, Mansfield, Boston, Luton

What is Air Tightness Testing?

What is air tightness testing? (Also known as Air Permeability testing or Air Pressure Testing). This is the process of creating a pressure difference between the inside and outside using a large fan that fits within the external door. We can then measure how leaky the building fabric is and identify where the leaks may occur.

Before air tightness testing is carried out, measurements are carried out in accordance with the ATTMA Publication,  Measuring air permeability of building envelopes (dwellings) as set out in Paragraph 3.14 of Part L1A 2013 of the Building Regulations.

All we need is plans and sections to carry out this measurement.

With our excellent background knowledge in sustainable design, assessment and testing, we are ideally suited to support you on your self build project. See the  example of the Essex Eco House.

We check what you need

We check the SAP Calculation for the target air permeability for each plot, then we know if we can test just a few and to what standards we need to achieve.

The target air permeability for the building is a maximum of 10 m3/hr/m2. However, the results of the SAP Calculation (which determines the maximum carbon emissions of the building) is likely to mean this target reduces significantly.

The actual target for air tightness testing may be 4 or 5m3/hr/m2 which means the building has to have 50% less uncontrolled air leakage to pass Building Regulations.

Air Tightness testing

We give you support and guidance

We will send an air tightness testing checklist before we test so you can check everything is complete and ready for the air test.

The most common areas for failure includes where the soil and vent drainage pipe runs vertically through the building. This is boxed in by plasterboard. But the blockwork behind it is unsealed and very often, this acts like a chimney.

Ensure the SVP is sealed att the top and where the bathroom and kitchen connects to the pipe. Also seal the base ad sides of plasterboard prior to installing the kitchen and bathroom.

Further tips HERE


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