Air leakage testing

for London and the South East

Air permeability testing for Part L compliance. Call 0203 837 4912.
Find out more

Single dwellings

from £170.00 plus VAT*

A building air leakage test compliant with ATTMA TSL1.

Building Regulation certification available within 24 hours.

Guidance concerning potential air leakage points and options for remedial work where necessary.

Get in touch * price dependent on size and location.

Multiple dwellings

from £55.00 plus VAT*

A building air leakage test compliant with ATTMA TSL1.

Building Regulation certification available within 24 hours.

Guidance concerning potential air leakage points and options for remedial work where necessary.

Get in touch * price dependent on number of dwellings being tested per site visit.



As registered members of the Air Tightness Testing & Measurement Association (ATTMA) you can rest assured that our air leakage test certificate will be accepted as evidence for Building Regulations sign-off.


Our engineers have experience of carrying out a successful air pressure test on dwellings of all types and sizes. For added piece of mind we will be happy to assist you with free advice and guidance throughout the construction process.

Health & Safety

Like you, we take health and safety seriously. All of our engineers are CSCS certified.


Building Regulations sign-off is often time-constrained and stressful. We aim to complete every air permeability test within five working days from the point of engagement and shall attend site at a time that is convenient to you.


We can provide you with a single point of contact to serve all your Part L, Part F and Part G requirements. In addition to conducting your air pressure test, we can provide SAP calculations, Energy Performance Certificates, water calculations and extract fan flow rate testing.

Price Promise

We intend for every quote to be the most competitive. If you find a like for like quote cheaper elsewhere we will try and beat it.

I have used Energytest for the past few years & have been completely satisfied with their professional service. They are very experienced & take the time to explain how improvements can be made to achieve the required results. I would recommend them to anyone seeking a professional value for money service.

- Keith Carter, Carter Land & Development Ltd

The service we receive is always professional and to the highest standards from the pre-testing to final inspections.

- S Osborne, RI Design & Build

About us

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Frequently Asked Questions

Site requirements for a building air leakage test

  1. The integrity of the structure must be complete prior to the test. Please see “How can I improve the air tightness of dwellings?” below.
  2. Our engineer will need access to an external door (approximate size 2.1m high x 0.9m wide) and an electrical supply within 25 metres of the doorway.
  3. All controlled ventilation openings will be sealed with polythene sheet or self-adhesive tape during the test. These include mechanical ventilation fans, window trickle vents and open flues/chimneys.
  4. All exterior doors and windows must be kept closed during the pressurisation tests. The actual test (after set up) is usually completed in well under one hour. During this period no personnel should enter or exit the building. It is preferable that the building is unoccupied.

Prior to attending site we shall require the following information

  1. Floor plans and section drawings;
  2. Design-stage SAP reports for each dwelling to be tested; and
  3. Contact details for the site manager.

What is an air leakage test?

An air leakage test is a test to determine the level of uncontrolled air flow through gaps or cracks in the fabric of a building. The result of the air leakage test is expressed as a quantity of air leakage (m3 per hour) per square metre of building envelope.

The general requirement of Approved Document L1A is that each dwelling tested must achieve a maximum air permeability rate of 10m3/h/m2. However, in order to comply with the carbon emission target a lower air permeability rate may be required. The required air permeability rate for each dwelling can be found on the design-stage SAP report for that dwelling.

Too much air leakage leads to unnecessary heat loss (and consequently, higher CO2 emissions) and can lead to discomfort to the occupants through cold draughts.

Do I need an air pressure test?

If you are constructing a dwelling then Approved Document L1A states that, with few exceptions, you must perform an air pressure test. For developments of two or more dwellings an air leakage test should be carried out on the lower of:

  1. Three units of each dwelling type; or
  2. 50% of all instances of that dwelling type.

For developments where no more than two dwellings are constructed, it may be possible to avoid the need for any pressure testing by using an assumed value of 15m3/h/m2 within the DER/TER calculations. Your SAP assessor will be able to confirm if this is the case for your dwelling.

What happens if the dwelling fails the air leakage test?

The majority of dwellings tested achieve a first time pass. However, should your dwelling not achieve a first time pass we shall advise you of all air leakage hot-spots and appropriate remedial work. If it is possible for the remedial work to be carried out at once we shall allow a reasonable amount of time for the works to be complete and then re-test at no extra charge. If it is not practical to carry out the remedial work on that day we will arrange for one of our air test engineers to attend site again on another day once the works are complete.

How can I improve the air tightness of dwellings?

  1. Refer to the Communities and Local Government accredited construction details.
  2. Seal any gaps where pipes and cables pass through the building envelope.
  3. Seal any gaps around windows and doors.
  4. Drylining is notoriously susceptible to air leakage. Ensure that the plasterboard is continuous (i.e. there are no holes behind fitted units, sinks/baths, etc). When drylining directly on to an external wall the plasterboard should be mounted on ribbons of plaster or adhesive around all the edges rather than dabs. Ensure the joints between boards are sealed and the plasterboard is correctly detailed at joints, corners, reveals and window sills.
  5. Draught strip all windows and doors.
  6. Draught strip any loft hatches.
  7. Seal holes around light fittings and pull cords in the ceiling. If the light fitting is not airtight then install an airtight box over the light fitting in the ceiling void.
  8. Ensure there is a good seal around boiler flue pipes.

Get in touch


0203 837 4912

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