Air Tightness Testing

At A1 Air Testing we provide the highest quality air leakage testing services. If you are looking for professional and cost-effective air testing, then look no further.

What Buildings do we test?

We offer Air Tightness Testing to a wide range of Buildings ie. Houses, Bungalows, Flats, Passivhaus Builds, and Small Commercial Buildings.
Our air leakage services are available nationwide, with our local service areas being Peterborough, Cambridge, Norwich, Kings Lynn, Boston, Lincolnshire, Cambridgeshire, Northamptonshire, Norfolk and Suffolk.

What is an Air Tightness Test?

Air Tightness Testing is a recognised method of measuring the extent to which air is lost through leaks in the fabric of the building. It is sometimes referred to as air leakage testing, air pressure testing or air permeability testing .... Too much air leakage leads to unnecessary heat loss and discomfort for the occupants.

Self Builds

Self Build Air tests can be very confusing for the Client. We aim to simplify things for you and provide you with the right information on how to achieve Self Build Homes with low Air Leakage Results. And identifying Air Leakage Paths and Areas in your Home while carrying out the Air Tightness test.

For more information please get in touch, and we will be happy to help!

The following basic steps are typical:

  • Check site preparation / Prepare site – including temporary sealing
  • Calculate the envelope, this is prefered to be calculated prior to site visit
  • Explain the process to relevant staff and sub-contractors working on or near the building
  • Take environmental condition measurements – wind speed, temperatures, barometric pressures
  • Install fan into door / opening
  • Connect monitoring equipment
  • Check the static pressure before test
  • Take multiple pressure difference readings and record fan flow rate(s) – allowing sufficient time for the pressure readings to stabilise
  • Check the static pressure after the test
  • Input the data readings into software – check that readings are at the right standard for test
  • Calculation of the results from test pass or fail
  • If the building fails, we pinpoint key leakage paths and help client/ staff on remedial work
  • Then rerun test stage again
  • Note results pass or fail / discuss results with client
  • Disconnect measurement equipment
  • Remove the fan



Air Testing Process

Prior to Test

The client is required to send a detailed set of plans to A1 Air Testing so that they can carry out envelope area calculations. Also required is the design air permeability rate / target air permeability; normally found on the SAP calculation.


This involves the client. At this stage it is important that the client ensures the building is up to the standard of testing, making sure that all cracks and gaps are sealed i.e Skirting boards, architraves, and incoming pipes are sealed. A sealing check list is available if required.

If the client wishes A1 Air Testing to complete the pre-test preparations, a fee will be charged according to the size of the new build.

The Test

On the day of the test it would be preferred if there were no tradesmen working within the building to which the test is to be completed; as they may effect the test procedure. The client should temporarily stop all extractor fans, close trickle vents or temporarily seal trickle vents and temporarily seal MVHR outlets.

The equipment will then be put in place and the test will be performed. The client will be notified of the results as soon as the results are verified by the inspecting technician.


If the test results indicate a Pass, a certificate will be issued within 24hrs.


If the test results indicate a Fail to meet targets the client will be consulted and offered reasons why the test may have failed. The technician will also inform the client of what remedial work needs to be completed.

For more information on Air Tightness Testing or how A1 Air Testing can help you, please get in touch.