Air leaks are one of the most common and costly causes of energy loss in homes and commercial buildings. Whether you’re looking after you’re home, managing a rental property, overseeing a commercial office, or improving a new build, detecting leaks early is essential to safeguard energy efficiency, reduce maintenance costs, and optimise overall performance.
Air leak detection methods include:
- Identifying common signs of air leaks, from whistling sounds to rising energy bills.
- DIY methods, such as visual checks and hand tests, which have their limitations.
- Professional air tightness testing and thermographic testing, which provide accurate and reliable results.
In this guide, we’ll further explore how to detect air leaks, explain why DIY methods are helpful but not comprehensive, and show how professional air tightness testing provides the most accurate and reliable results.
Ready to stop wasting energy through air leaks and improve your building’s performance? Book your professional air tightness test with Falcon Energy today, available nationwide.
What are air leaks, and why do they matter?
A building air leak is any unintended gap, crack, or opening that allows uncontrolled airflow in or out of a property. These leaks are commonly found around doors, windows, insulation gaps, ventilation ducts, or where pipes and cables pass through walls and ceilings.
Even small leaks can lead to significant inefficiencies over time. When left unchecked, air leaks contribute to a range of problems:
- Energy loss, as heated or cooled air escapes from the building envelope.
- Higher energy bills and unnecessary maintenance costs.
- Reduced indoor comfort, with cold drafts, uneven temperatures, or stuffy rooms.
- Increased wear on HVAC systems, which must work harder to maintain stable conditions.
- Elevated carbon emissions, undermining sustainability efforts and energy performance goals.
Early air leak detection is crucial. Identifying and sealing these leaks not only improves comfort and energy efficiency but also ensures your building remains compliant with modern standards. Ignoring them allows ongoing energy waste and can lead to long-term degradation.
Common signs you might have an air leak
Here are some of the most common warning signs to look out for:
- Whistling or hissing sounds can occur near doors, windows, and ventilation points.
- Drafty areas or inconsistent room temperatures, especially near exterior walls or poorly sealed frames.
- Unexplained spikes in heating or cooling bills, despite no change in usage or weather.
- Dust, moisture, or even mould build-up around vents, seals, or ducts is often caused by unregulated airflow.
- Noticeably reduced airflow or low pressure from HVAC vents or ventilation systems.
- Subtle changes in ambient noise, such as faint hissing or a drop in system performance, especially during high-demand operation.
If you’re experiencing one or more of these issues, it’s likely that an air leak is present and requires attention. Early detection through professional air tightness testing can prevent long-term energy waste and help restore your building’s performance.
To learn more about air leaks, take a look at our guide on Common Sources Of Air Leaks In Properties.
DIY air leak detectors and testing methods
Before investing in professional services, there are a few simple checks you can carry out yourself at home or on-site. These DIY air leak detection methods can help you identify obvious problem areas:
Smoke pencils or thermal apps
Affordable tools, such as hand-held smoke pencils (also known as air leak detectors) or smartphone-compatible thermal imaging apps, can help visualise temperature differences or air currents in real-time.
Visual inspection
Walk through your property and inspect windows, doors, and areas around pipes or ducts. Look for visible gaps in caulking, cracked seals, or holes where air might be escaping.
Hand test
On a breezy day, slowly run your hand along the edges of doors, windows, and wall joints. Even minor drafts can often be felt by hand.
These DIY techniques help spot surface-level leaks, but they only provide a basic overview. They won’t quantify air leakage, detect hidden problem areas, or confirm whether your building meets energy efficiency regulations.
To fully understand the extent of air loss and ensure compliance, a professional air tightness test is essential. It delivers accurate, measurable results that DIY tools can’t match.
Professional air leak detection techniques
At Falcon Energy, we specialise in industry-approved techniques that deliver precise, measurable results – blower door testing and thermal imaging. These methods help identify both evident and hidden air leaks across residential and commercial buildings.
Blower door testing
This is the most widely used and trusted method for air tightness testing. A large fan is temporarily installed in a door or window opening to either pressurise or depressurise the building. This process measures the overall air leakage rate and forces air through gaps, allowing the team to pinpoint leaks using pressure differentials.
It is essential for:
- Proving compliance with Building Regulations like Part L.
- Locating leaks around doors, windows, loft hatches, ductwork, and other areas of the envelope that are weak points.
- Assessing improvements after draught-proofing, insulation work, or renovations.
Blower door testing provides a clear, data-driven view of how airtight your building really is, ensuring nothing is left to guesswork.
Thermal imaging
Also known as thermographic testing, this method uses infrared cameras to detect cold or hot spots that indicate where air is escaping or entering. It’s a fast, non-invasive way to identify leaks that are otherwise invisible, particularly in:
- Walls, ceilings, ductwork, and insulation voids.
- Properties with suspected heat loss or inconsistent internal temperatures.
- Situations where visual evidence is needed to support targeted repairs.
These methods provide quantifiable results to demonstrate compliance with Building Regulations, enabling the monitoring of performance over time and the detection of future leaks early. They also provide detailed diagnostics to guide targeted repair and upgrade strategies, offering better assurance of building efficiency, comfort, and indoor air quality.
Other available methods
While Falcon Energy specialises in air tightness testing and thermographic testing, other niche methods, such as ultrasonic or tracer gas detection, are sometimes used in industrial or pressurised systems, which are not typically required for standard air tightness assessments.
DIY vs. professional air leak detection
| Consideration | DIY Methods | Professional Testing |
|---|---|---|
| Accuracy | Basic – may spot obvious leaks | High – identifies both visible and hidden leaks |
| Tools Required | Smoke pencils, thermal apps | Blower door equipment, infrared cameras |
| Quantifiable Data | No | Yes – measured leakage rates |
| Regulatory Compliance | Not suitable | Fully compliant and certifiable |
| Detection of Hidden Leaks | Rarely | Yes – even in walls, ceilings, insulation voids |
| Time & Effort | Quick but incomplete | Thorough and professionally conducted |
| Suitable For | Basic checks, minor repairs | New builds, refurbishments, and property certifications |
Why professional air tightness testing is essential
Air tightness testing is crucial for understanding how much air is unintentionally escaping from a building, which directly affects energy efficiency, comfort, and regulatory compliance. It helps identify performance gaps that DIY methods miss, allowing for precise improvements and long-term energy savings.
This testing is also essential for meeting building regulations, which require measured leakage rates in new builds and major refurbishments. Without professional testing, leaks often go undetected, resulting in increased bills, higher carbon emissions, and accelerated wear on heating and cooling systems.
At Falcon Energy, we specialise in delivering this essential service with certified experts, advanced equipment, and detailed reports tailored to both residential and commercial properties. We’re proud to offer reliable results, excellent customer service, and peace of mind.
Summary: Detect air leaks before they cost you
Air leaks may be hard to see, but their effects are very noticeable. They lead to higher energy bills, reduce indoor comfort, strain building systems, and jeopardise compliance with modern standards. While DIY methods can reveal surface-level issues, they often fail to capture the whole picture.
For accurate, dependable results, professional air tightness testing is required. Don’t leave your building’s performance to chance; early detection leads to long-term savings, safety, and sustainability.
Book an air tightness test with Falcon Energy
Whether you’re planning a new build, upgrading an existing property, or preparing for a regulatory inspection, Falcon Energy is here to help with nationwide coverage, fully trained experts, and years of trusted industry experience.
Book your professional air tightness test with Falcon Energy today. Call 01403 253439 or submit our contact form.
How to detect air leaks FAQ
How much do air leaks cost?
The cost of air leaks can vary widely depending on the size and number of leaks, but even minor gaps can result in significant energy loss over time. A small, unsealed area can waste hundreds of pounds a year in heating or cooling costs. Leaks also increase wear on HVAC systems, resulting in more frequent repairs and shorter equipment lifespan.
What device detects air leaks in houses?
A common device used to detect air leaks in houses is a blower door system, which measures the overall air leakage by pressurising or depressurising the building. Thermal imaging cameras are also used to identify hot or cold spots where air is escaping or entering. For simple DIY checks, tools like smoke pencils can help reveal airflow near windows, doors, and vents.
Are DIY air leak tests accurate enough?
DIY air leak tests are useful for spotting obvious gaps or draughts. However, they only detect surface-level leaks and often miss hidden or subtle issues within the building envelope. They also can’t measure the total amount of air leakage or provide the data needed for compliance with regulations. For accurate, comprehensive results, a professional air tightness test is strongly recommended.