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Air Tightness Testing

Building Air Tightness (also called Envelope Air Tightness) can be defined as the resistance to inward or outward air leakage through unintentional leakage points or areas in a building envelopeThis air leakage is driven by differential pressures across the building envelope due to the combined effects of external wind, temperature and mechanical ventilation systems. Air Tightness is the fundamental building property that impacts infiltration and exfiltration.

In today's new buildings over 45% of energy used to heat a property is used just in heating the air flowing through the building caused by unintenional leaking. In older existing buildings - the energy use is even greater and can significantly impact heating costs.

Benefits of an Air Tight Building

An airtight building has several positive impacts when combined with an appropriate ventilation system, whether natural, mechanical, or hybrid:

  • Lower heating bills due to less heat loss caused by draughts and leaking

  • Better performing ventilation system, especially if heat recovery/reclaim system is installed

  • A quieter home, noise ingress is greatly reduced 

  • Reduced chance of mould and rot because moisture is controlled by correct ventilation

  • Fewer draughts and thus increased thermal comfort conditions

  • Overall much improved indoor air quality

  • Less cleaning required as dust and dirt brought in by air flow is reduced

Air Tightness Test Overview

Air Tightness Testing is the key feature of any energy efficient building;

  • Reducing wasted heat energy

  • Allowing a building’s atmosphere to be controlled with mechanical ventilation heat recovery units.

  • Helping  to create a healthier environment.

Air Tightness Testing is undertaken to find a building’s Air Permeability Rating and is an integral part of part L of the building regulations which needs new buildings to comply with specific air-permeability targets. We can locate where energy is lost in existing buildings as well as new constructions. Each air leak that is sealed will help to bring your heating costs down.

Our Air Tightness Testing Technician Is Here To Help

  • Manx Solar Electrical Ltd. offer on-site air tightness testing throughout the Isle of Man for commercial and residential buildings, new or old

  • We provide design stage Air Tightness consultancy for new builds, refurbishments, extensions and loft conversions

  • We present 'Pre' and 'Post' Combined Energy Reports, which will help you see the difference we have made

Achieving improved air tightness is a key factor for building contractors in meeting the government’s targets for reduced carbon emissions and improved energy efficiency by 2050. You can reduce your building heating costs, sometimes significantly, by as much as 40%, depending on how draughty your building is now.

Our Air Tightness Service

Our technician will assist in finding air leaks for 30 minutes while on site during the final air test and issue the Air Permeability result certificate and report to building control within 48 hours of conducting the test and the invoice being paid. Building control will advise you if the AP result is acceptable or if not another Air Tightness Test will be required at an additional cost.  Our technician is qualified to perform both L1 and L2 building air permeability testing and is registered with Isle of Man Building Control to the islands 2014 new build air testing standards:

  • L1 - Dwellings & Commercial properties up to a volume of 4000 cubic meters

  • L2 - Dwellings & Commercial properties in excess of volumes over 4000 cubic meter

Our prices start at £200 + VAT for an internal floor area of up to 100 square meters.​

Frequently Asked Questions

What is Air Tightness Testing?

Building regulations from October 2014 require that all new buildings comply with ‘Part L Conservation of Fuel and Power', which aim to reduce C02 emissions. This means that new dwellings and commercial buildings need to undergo air tightness testing which provides building control with an Air Permeability Rating for the property. Air Tightness Testing is the procedure to trace any unwanted draughts (uncontrolled airflow) through the house.  Too much air leakage can lead to significant heat loss resulting in higher C02 emissions, and high heating bills of the occupant.

When and How is an Air Tightness Test performed?

Building Regulations require an Air Permeability Certificate before they can issue a Habitation Certificate. An Air Tightness Test must be performed at the completion stage, however, at this stage any leaks could be hidden behind the decorated finished surfaces. Repairing air leaks at this stage can be costly in terms of reputation, expense, completion date and client satisfaction. We would recommend the following approach:

  1. Request a drawing review where we can point out potential areas of air leakage.

  2. Perform a pre-test when windows and doors are fixed and top floor ceiling is in place. At this stage any air leaks can be quickly identified and repaired and should leave the builder feeling confident.

  3. Achieve the required Air Permeability result at completion stage.

How Tight Does the Building Need To Be?

The 2014 building regulations require an air permeability result of:

Domestic Dwellings - 5.0 m³/m²/hr@50Pa

Commercial Buildings - 7.0 m³/m²/hr@50Pa

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