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Air Tightness Testing: When, How Much & How Long?

Air Tightness Testing: When, How Much, and How Long Will It Take?

Three of the most common questions about air tightness testing are: When should it be carried out? How much does it cost? And, how long does a test take?

In this article we’ll answer these questions.

When should an air tightness test take place?

The dwellings comprising a test sample should be chosen by the Building Control Body (BCB), working closely with the applicable air tightness testing firm. Around half of the tests for each type of dwelling should be undertaken during the building of the first 25% of the given dwelling type. The Building Control Body will receive the results of the tests, inclusive of any fails. This batch of tests are carried out at this early stage so that developers can learn any necessary lessons and make any modifications to the dwelling designs – or indeed make changes to their on-site procedures. It is in everyone’s interest to pinpoint issues before the majority of dwellings are completed.

Tests should only take place on buildings that are close to being complete.

How much does a test cost?

The cost of tests depends on various factors, including how many dwellings need to be tested and across how many locations they are distributed. With Air Tightness Testing Ltd., a single test costs from £190, with further tests on the same site starting at £40. A number of UK studies have demonstrated that a dwelling with excellent air tightness credentials can command a higher sale price due to reduced energy costs over the lifetime of the building.

How long does it take?

Usually under two hours. Once again, the precise answer to this question depends on various factors, chiefly: the size of the dwelling being tested, the number of apertures that must be taped over and the availability (or not) of building plans. Ideally these plans should be provided in electronic format. If the test is successful, details of the pass should be sent to the building control body within seven days.

What if the test fails?

A failed air permeability test demands that any problems are pinpointed. There are areas in dwellings where issues commonly arise, so identifying the problem is often straightforward. The issues should be addressed and a new test carried out. Tests should be repeated until the building passes. In such circumstances, another building of the same type should be tested, with a view to increasing the sample size.

iATS Registered and UKAS Recognised


We are registered with iATS (Independent AirTightness Testing Scheme) and use equipment calibrated by UKAS laboratories. Our testing procedures are also recognised by UKAS.