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Home Air Tightness Certificate
Air Permeability Testing
Retrofit, Domestic, Residential, Commercial, Plenums, Smoke Shafts.
Are you looking for a Building Air Tightness Test?
A home air tightness certificate, also known as an air permeability certificate or air leakage certificate, is a document confirming the results of an air tightness test performed on a building It provides a measure of how well a building is sealed against air leaks, which directly impacts energy efficiency and indoor air quality.
Our air permeability testing is routinely carried out using a blower door fan methodology. Following the methodology to ATTMA standards in line with CIBSE TM23 or ISO 9972:2015
Are you ready for your Air Test?
Click here to find our Air Permeability Site Status Checklist covering common leakage area preparation and recommended sealing
🏠 Home Air Tightness Certificate: Why It Matters and How to Get One
In today’s energy-conscious world, ensuring your home is energy efficient isn’t just a smart move—it’s often a legal requirement. One of the key components in achieving this is obtaining a Home Air Tightness Certificate. But what exactly is it, and why should homeowners and builders care?
Furthermore, we offer full reporting detailing suggestions for rectifications to reach target leakage rates.
What Is a Home Air Tightness Certificate?
A Home Air Tightness Certificate is an official document that confirms a building has passed an air permeability test, also known as a blower door test. This test measures how much air leaks out of (or into) a building through gaps, cracks, and other unintended openings in the building envelope.
The result is expressed in m³/h/m² at 50 Pascals, and it must meet the standards set by local building regulations—such as Part L of the Building Regulations in the UK.
With a valid certificate, the result can be inputted into a domestic energy assessment, to generate a energy performance certificate (EPC).
Why Is Air Tightness Important?
Air tightness plays a crucial role in:
- ✅ Energy Efficiency: Reducing heat loss means lower energy bills.
- ✅ Comfort: Eliminates drafts and maintains consistent indoor temperatures.
- ✅ Environmental Impact: Less energy use means a smaller carbon footprint.
- ✅ Compliance: Most new builds and major renovations require a certificate to meet building regulations.
When Do You Need a Air Test?
You’ll typically need an air tightness test and certificate:
- For new residential buildings before final sign-off.
- When applying for an Energy Performance Certificate (EPC).
- As part of Building Control approval.
- During major refurbishments or extensions that affect the building envelope.
How is a Blower Door Fan Test done?
A certified technician will:
- Seal all intentional openings (vents, chimneys, etc.).
- Fit a blower door system to an external door.
- Pressurise or depressurise the building.
- Measure the rate of air leakage by taking a range of data points at varying building pressures.
The process usually takes 20 minutes up to a few hours. This is dependant on the property size, amount of required temporary sealing and environmental conditions.
We are able to provide immediate results, and typically aim to get a formal test report issued within 48 hours of testing.
What Happens If You Fail The Air Test?
If your building home doesn’t meet the required standard:
- You’ll receive a report highlighting problem areas.
- You may need to carry out remedial work (e.g., sealing gaps, improving insulation).
- A retest will be required to obtain certification.