Airtightness Testing

Airtightness Testing

Please enquire for a cost on the airtightness testing and provide plans and number of dwellings to enable costing.

Air tightness testing is a recognised method of measuring the extent to which air is lost through leaks in the building fabric. It is sometimes referred to as air leakage testing or air pressure testing.

Air pressure testing, also known as air tightness testing, is the process of measuring the amount of air leakage from a building through uncontrolled ventilation. A fan is used to either pressurise or depressurise the building to around 50 pascals and the result is described as the air permeability of the building.

The primary way airtightness is tested is via a blower door test. During a blower door test, a fan is installed in the door or window of the building to be tested. The blower door machine then pressurises or depressurises the building to force air through any cracks or gaps in the building envelope.

It suggests that air permeability is the physical property used to measure the airtightness of the building fabric. It is defined as air leakage rate per hour per square metre of envelope area at a test reference pressure differential across the building envelope of 50 Pascal (50 N/m2).

An air leakage test needs to be carried out on new-built residential properties for Building Regulations (as per Approved Document L1A). Air leakage testing is also known as air testing, air pressure testing and air tightness testing

Air tests are typically needed once a residential or commercial building has been constructed. According to Building Regulations, there’s certain properties that require an air tightness test: New build residential properties and ones over a certain size (500 m2) must require an air tightness test before being sold.

Airtightness and Background Ventilation Testing

We have trained surveyors in both the blower door fan method and the low pressure pulse test method. The pulse test being our preferred due to the accuracy, efficiency and least disruptive method. The pulse technique is an innovative compressed air based alternative to the blower door fan and is recognised as an approved method for both new build and existing dwelling in England, Wales and Scotland.

Air leakage in buildings typically accounts for a third of total heat loss, with the associated air movement also a significant source of discomfort for occupants. Just as importantly, the level of air leakage also plays a vital role in determining the ventilation strategy for a given building and therefore is often a key factor when it comes to addressing the root cause of damp, condensation and indoor air quality issues.

Landlords and Homeowners:

From April 2023 all rented properties will require a minimum EPC rating of E and in 2025 this will move to a rating of C. At the moment an EPC is produced based on estimated performance. Airtightness testing allows the landlord to know how the property is performing in terms of air leakage and therefore heat loss. This often helping to provide a landlord with an improved overall EPC rating.

Test results can then also be used to help target further improvements to the property, delivering not only energy and running cost savings but also helping to inform the overall ventilation strategy for the home. Very often the root cause of damp, mould and condensation issues are related to areas of the home either being air tight and under ventilated or excessively leaky, hard to heat and cold.

Retrofit Installers: 

In addition to the EPC rating benefits, PAS2035 and other such technical standards strongly encourage air tightness testing to be carried out pre and post retrofit upgrade works. For installers, the test results will help inform what measures are best suited to a home and allow you to demonstrate to your clients how much you have improved a property by.

New Build:

As of June 2022, all new build properties require airtightness testing for building regulation compliance purposes. The current average air permeability score for new build homes is 4.5m³/m².h@50Pa but with care and attention to detail, this can easily be halved to 2m³/m².h@50Pa or better which in turn makes compliance on the overall dwelling emission rate (DER) much easier to achieve. Our service to new build developers is most efficient when we are presented with multiple plots to test in the same location on the same day.

What does the testing involve?

Our Pulse equipment allows us to test a building and produce a test report for the property in as little as 15 minutes. The process typically entails:

• Arrive and the property and place the Pulse equipment centrally on the ground floor
• Whilst our portable compressor charges the air tank, we take measurements of the building volume and envelope area. We also make sure all external windows and doors are closed and internal doors open.
• When we press go on the Pulse equipment, the test itself takes just 15 seconds, presenting the result on the screen of the controller. The air leakage rate is measured directly at low pressure and is much less disruptive than a fan test.
• We then upload the test data to an online portal where we generate a digital report.