Air Tightness Testing

Air Tightness

What Is Air Tightness Testing?

Air tightness testing measures how airtight a building is by calculating the rate at which air escapes through uncontrolled gaps in the structure. During the test, a blower door fan is fitted to an external doorway to pressurise or depressurise the property while readings are taken from specialised equipment.

The result is expressed as m³/h·m² at 50 Pascals (air changes per hour), and your building must meet or exceed the threshold defined by Building Regulations.

Air tightness testing ensures your home is energy efficient, comfortable and cost-effective to run.

Why Air Tightness

Why Air Tightness Testing Is Required

Modern homes are built to increasingly strict energy efficiency standards. As insulation improves, controlling air leakage becomes essential to prevent heat loss and reduce carbon emissions.

A successful air tightness test:

Demonstrates compliance with Part L
Reduces heating bills by minimising heat loss
Improves comfort by eliminating draughts
Supports high SAP/EPC ratings
Ensures ventilation systems function correctly
Prevents moisture problems linked to leaks

Without a compliant test result, Building Control cannot sign off a new dwelling.

Why Choose

Why Choose Home Energy EPC?

Our air tightness testing specialists provide quick, efficient and client-focused testing that keeps your build on schedule.

What You Can Expect:

Fully qualified, experienced testers
UKAS-recognised blower door testing equipment
Fast appointment availability
Clear pass/fail results on-site
Practical advice to improve weak areas
Retests available at discounted rates
Multi-plot developer discounts
Combined testing packages (SAP EPC + Ventilation + Sound)

We pride ourselves on being easy to work with — especially for tradespeople and self-build clients.

Works

How Air Tightness Testing Works

Air tightness testing is a straightforward and efficient process when the building is correctly prepared.

Equipment Installation

A blower door system is fitted to an external door, sealing the doorway. This fan pressurises or depressurises the building to measure airflow.

Building Pressurisation

The fan creates controlled pressure differences inside the property while sensors measure the air movement required to maintain that pressure.

Air Leakage Measurement

We monitor how quickly air escapes through gaps, joints, vents, pipe penetrations and other openings.

Data Analysis and Results

We calculate your air permeability score and confirm whether it meets Part L requirements.

Advice and Guidance

If improvements are needed, we identify leakage points and offer practical fixes.

Certification

You receive a full Air Permeability Test Certificate, required by Building Control.

Most tests take 20–60 minutes depending on property size.

Test

How to Prepare for Your Air Tightness Test

Correct preparation is essential to achieving a pass. Before testing, ensure:

All external windows and doors are fitted and close properly
Loft hatches are installed and sealed
Service penetrations are filled or sealed
Skirting boards and plasterboard are complete
Trickle vents are open
Extractor fans and ductwork are installed
Brush strips and seals are fitted to doors

Construction should be paused during testing to avoid air disturbance.

Common Causes

Common Causes of Air Test Failure

Air tightness failures usually occur due to minor but widespread leaks. Typical issues include:

Gaps around pipework penetrations
Poorly sealed loft hatches
Unsealed sockets or electrical service points
Gaps behind skirting boards
Poor sealing around window frames
Unfinished mastic or caulking work
Holes in plaster or plasterboard

We help identify these issues on-site to support quick retesting.

Who Needs

Who Needs Air Tightness Testing?

You require an air tightness test if you are:

Building a new residential dwelling
Converting a property into flats
Undertaking a major renovation with energy efficiency requirements
Constructing an extension assessed under Part L

Most new builds are required to undergo testing before completion.

Offer

Pricing

Our pricing is competitive, transparent and based on property size and number of tests needed. We offer:

Single-plot testing
Multi-plot developer discounts
Combined testing packages for full Part L compliance

let’s make it shine!

Book Your Air Tightness Test Today

If you’re building a new home, developing multiple plots or completing a conversion, Home Energy EPC provides professional, compliant and efficient air tightness testing to keep your project on schedule.

info@homeenergyeepc.co.uk

0121 000 0000

Book your blower door test today and ensure your property meets all energy efficiency and Building Regulation requirements.