May 29, 2025
Introduction
When people think about saving energy or improving comfort in a building, they usually focus on upgrading the HVAC system. That makes sense, a well-designed system can have a big impact on how a building feels and how much it costs to operate. But here’s something that’s just as important and often overlooked: air barrier testing.
If your building has hidden leaks in its walls, roof, or windows, even the best HVAC equipment won’t perform the way it should. These leaks make it harder to maintain temperature, waste energy, and put extra strain on your systems.
In this blog, we’ll break down what air barrier testing is, why it’s so important, how it helps HVAC systems work better, and what to expect during the testing process. Whether you’re managing new construction or an existing building, this guide will help you see how sealing your envelope can save money, improve comfort, and help your building last longer.
What Is Air Barrier Testing?
Air barrier testing is a process used to find and measure air leaks in a building. These leaks allow outside air to get in, and inside air to escape in ways that aren’t supposed to happen. When that happens, your HVAC system has to work much harder to keep people comfortable.
Testing measures how much air leaks through gaps, cracks, or poorly sealed areas in a building’s envelope. The most common method is a blower door test, where a large fan is set up in a door frame to pressurize or depressurize the building. Technicians can then measure how much air is moving through unintended pathways.
Other tools include:
- Infrared cameras to detect temperature differences and show where air is entering or escaping
- Smoke pencils or fog machines to visibly track the movement of air
- Tracer gases for more detailed investigations in complex buildings
Together, these tools help pinpoint problem areas that can then be sealed and fixed.
Why It Matters for HVAC Performance
Air leaks might seem minor, but they have a major impact on how your HVAC system works. When warm air escapes in the winter or cool air leaks out in the summer, your HVAC system has to keep running to make up for the loss. That means:
- Higher energy bills
- Increased equipment wear and tear
- More frequent repairs and replacements
- Uneven temperatures and occupant complaints
Leaky buildings also make it hard to maintain proper air pressure and humidity. That leads to more than just discomfort, it can affect indoor air quality, encourage mold growth, and reduce productivity in commercial spaces.
Proper air sealing allows HVAC systems to operate efficiently and consistently. When your system isn’t constantly fighting leaks, it runs smoother, lasts longer, and costs less to operate.
Air Barrier Testing and Energy Codes
More cities and states are requiring air barrier testing in new construction. Energy codes like the IECC (International Energy Conservation Code) and ASHRAE 90.1 set limits on how much air a building can leak. These codes exist for good reason, airtight buildings use less energy and are easier to control.
Failing an air barrier test during construction can lead to delays, rework, and added costs. On the other hand, passing your test helps ensure code compliance and can make it easier to earn green building certifications like LEED, ENERGY STAR, or WELL Building Standard.
Real Results: A Case Study
Let’s look at a real example. A 70,000-square-foot office building in Florida had recently upgraded its HVAC system. Still, the energy bills stayed high, and tenants kept reporting hot spots and humidity issues.
An air barrier test revealed several gaps around windows, poorly sealed utility penetrations, and roof-to-wall connections that weren’t airtight. After sealing those leaks and adding insulation, the building saw:
- A 20% drop in annual energy use
- Fewer HVAC service calls
- Much more stable indoor temperatures
- Happier tenants and fewer complaints
The building owner recovered the cost of the testing and sealing work within 18 months, and now saves thousands of dollars each year.
When Should You Test?
For New Construction:
The best time to do air barrier testing is after the building envelope is complete, but before the interior finishes go in. That makes it easier to fix issues before they become expensive or cause delays.
For Existing Buildings:
Air barrier testing is also useful in older buildings. Maybe you’ve noticed rising energy bills, uneven temperatures, or problems with humidity. Testing can reveal leaks you didn’t know were there. It’s also a great step to include before replacing an HVAC system, there’s no point in installing new equipment in a leaky building.
What Happens During the Testing Process
A typical air barrier test takes several hours. Here’s how it works:
- Set up: Technicians walk the building and temporarily seal intentional openings like vents and chimneys.
- Testing: A blower door is used to pressurize the building and measure how much air is leaking through unsealed areas.
- Inspection: Smoke tools, thermal cameras, or tracer gases are used to find exactly where leaks are happening.
- Report: You’ll receive a report showing the overall leakage rate and the specific areas that need attention.
- Fix and Retest (if needed): Once leaks are sealed, a second test confirms that improvements were successful.
Common Problem Areas
Some parts of a building are more likely to leak than others. Testing often reveals issues in areas like:
- Around doors and windows
- Roof-to-wall joints
- Electrical outlets and light fixtures
- Plumbing and utility penetrations
- Unsealed attic or basement access points
- Cracks in the foundation or building envelope
Even small gaps can let in a surprising amount of air. Sealing these areas can dramatically improve your building’s performance.
How It Helps with HVAC Commissioning
If you’re also planning HVAC commissioning or test and balance (TAB) services, air barrier testing should be part of the plan. A tightly sealed building makes it easier to balance airflow, measure pressure, and verify that your HVAC system is working as designed.
Without good airtightness, airflow measurements can be misleading, and pressure control becomes much harder. Testing the air barrier first means fewer surprises during commissioning and a much smoother process overall.
Big Benefits in a Simple Step
To summarize, air barrier testing offers major advantages for both new and existing buildings:
- Lower energy bills
- Improved HVAC system performance
- Longer equipment life
- Fewer repairs
- Better comfort and indoor air quality
- Compliance with modern energy codes
- Support for green building certifications
While air barrier testing might not be the flashiest part of a building project, it’s one of the most cost-effective ways to ensure long-term performance. It protects your investment and gives you data to make smart decisions about maintenance, upgrades, and energy use.
Final Thoughts
A well-sealed building envelope is the foundation of HVAC efficiency. Without it, even the most advanced systems can fall short. Air barrier testing helps you catch problems early, fix them before they get worse, and get the best performance possible out of your building and systems.
In today’s world, where energy efficiency and indoor air quality matter more than ever, this kind of testing isn’t just a nice-to-have — it’s a must.
Call to Action
If you’re building a new space, planning a renovation, or just trying to solve an ongoing HVAC issue, air barrier testing is a smart next step.
Contact us today to schedule a test or learn more about how we can help improve your building’s comfort, efficiency, and performance.
