Green building practices are on the rise, and so are strong, energy-efficient building envelopes. The Washington State Energy Code now requires performance testing, which is why whole-building air barrier testing has seen a big boost in the last 3–5 years. In the Pacific Northwest, the trend shows no sign of stopping.
When clients tackle air-tightening for the first time, they keep repeating one question: “Why should we run a whole-building air barrier test?” New construction is under constant pressure to trim energy use, and demand for lower energy bills feels endless. After investing heavily to heat and cool a space, the last thing anyone wants is for that precious, conditioned air to pour out through hidden holes and seams. A whole-building air test reveals how tightly the envelope is sealed and flags where air is escaping. In simpler terms, the test is a final quality-control checkpoint. It lets every trade on the job site know that the building is both well-constructed and energy-efficient.
Choosing the right testing agency can be confusing. There are plenty of firms out there. This writing doesn’t aim to sell ; it aims to shine a light on the less-visible corners of the air-sealing industry.
Importance of Equipment and Experience
The first thing to check with your testing company is whether they use calibrated tools. Using uncalibrated gear can easily generate either a false pass or a false fail—neither of which you can afford. Every single test must strive for laser accuracy right from the start with properly calibrated and well-documented equipment. I can’t count how many times a client has asked for a second opinion after the first test showed an outrageous failure, only to find out the technician botched it with a rake of uncalibrated gear and zero formal training.
This leads straight to technician training and certification. Sure, anyone can buy a few fans on eBay and jam the big green button. But in Washington, this test is the final hurdle for your occupancy certificate, and it can also snag you energy tax credits or a few LEED points. Precision is the name of the game, and the technician is a major player. Solid training usually means certification from the equipment manufacturer, a licensed mechanical engineer, or well-recognized bodies like ABAA or Passive House.
Using training to really grow means you pick a real program from a trusted place. A good program gives you up-to-date tools, clear feedback, and a network you can lean on later. Going this route shows you care about sticking to best practices and being ready for whatever comes next in your field.
When it comes to whole building air barrier testing, both how the building is set up and how the testing equipment is calibrated matter a lot. Yet, it is the skill of the technician running the test that really makes the difference.
Building Preparation
Several building systems are kept out of the test. In a typical mid-rise apartment building, for example, Bathroom exhaust fans, dryer vents, range hood exhausts, AC diffusers, and the supply and exhaust fans serving the common hallways must all be effectively sealed. If even one of these is left open, outside air can leak in, which can skew the results.
The goal is the same: prevent air from coming or going through these ducts. The methods we use, however, change. Large dampers, blank-offs, and temporary barriers might be set in place. Regardless of the building or the technique, Company always handles these isolation tasks for our clients to ensure a clean, accurate test.
By having Company train our own staff to prep the building, we remove the contractor and their crew from the prep risk, so nobody gets stuck with a failed test due to a bad install. We use the right materials and methods, every time. The contractor saves time and money on labor and supplies because the testing agency does the prep right the first time.
For the plumber and electrician, excluding their systems is pretty simple. For plumbing, just keep the P-traps full of water, and you’re good. For electrical, look for conduits that lead to the outside and make sure they have smoke seals or are temporary—stuff the openings with fire-rated foam or caulk. Just double-check with the electrician or plumber for the code-approved sealing method.
Prop every interior door so it stays open. Close and lock every exterior door and window. Simulate the temporary conditions we often forget: weatherstripping, door sweeps, or any incomplete detail. The less incomplete work you have, the better the test result will be.
Clearly, getting the building ready is a key part of any successful test.
After years in the field, we’ve found the best team for building prep before air barrier testing is the testing agency—us. We know the process inside and out, and we move quickly. Imagine what happens if a team without experience tries the prep and the test fails because they didn’t seal a door right or left a gap. We’ve watched that play out, and it ends up being a political headache for everyone involved. That’s why Company always includes building prep in every proposal for air barrier testing.
Test Equipment and Industry Standards
Setting up testing equipment requires a careful mix of strategy and organization. During a test, we might lay out hundreds—even thousands—of feet of power cords, pressure tubes, and computer cables, along with countless little parts. Since every detail counts, a single pressure tube misplaced in the wrong location could throw off the entire result. Again, the skill and training of the testing tech become essential. The photo at the top of the page shows a test on a 200,000-square-foot K-8 school, run with nine fans. We moved about 2,500 feet of hoses, cords, and wires for that one test.
Like every air barrier test we run, this one follows specific industry standards.
The two most popular test standards for measuring airtightness are ASTM E 779 and ASTM E 1827. Others exist, but ASTM E 779 is by far the most frequently used. Each of these standards contains detailed equations—sometimes numbering up to seven pages—necessary for turning the test data into final results. Because the math is so complex, most testing companies rely on software to handle both the calculations and the test equipment. Using software not only produces results that are consistent and precise, it also reduces the chance of human error. The technician still has to enter key information, like wind speed, the size of the building envelope, area of each floor, and elevation above sea level. The software is not a legal requirement for the test, yet it is the fastest and most reliable option for most professional testers.
Thanks to advances in the industry, air barrier testing has become quicker and more cost-effective. Despite this, some still believe that testing the entire building envelope has to be a costly affair.
You may be surprised its price is lower than ever, especially for straightforward structures like single-family houses and townhomes. Larger commercial buildings, along with mid- and high-rises, require more complex tests, so fees for those will vary. Still, the days of spending $50,000 for tests are behind us. In the past, these detailed tests could take a full week to prepare and execute. Now, we typically finish them within a single day—and only two days when the setup is especially tricky. We’ve cut this time thanks to smarter equipment and extra training for our test technicians.
While construction is booming and more people want greener buildings, I advise we all pull together to create tight, efficient envelopes. Gather our design, construction, and inspection teams to review specs and details side by side. From the start, outline a testing plan, and then check the air-leakage results against those goals when the building is complete.
Our team is ready to support you through every testing requirement. Company is a trusted resource within the industry, so don’t hesitate to call us for extra help on this project—or on the next one.
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