Listen for Leaks
The Portascanner uses ultrasonic technology to isolate the smallest air leaks, making it easier to air-seal an enclosure.
I use a blower-door test to determine the leakage rate of a room or an entire building; however, tracking down isolated leaks is a whole different story. Finding air leaks can be done by watching for fluttering drapes or spiderwebs, feeling for air movement, using synthetic smoke created by smoke-generating tools, capturing thermal images, or measuring pressure differentials between spaces inside the building enclosure using a manometer. I’ve recently been trying out a new tool that uses a novel method to find air leaks: ultrasonic frequency.
Sound travels on air, creating a pulse in air pressure. This “noise” has the ability to travel through very small holes. This is the science behind ultrasonic air-leak detection. Coltraco, a British company, has developed a tool called the Portascanner using this technology.
It works by using a frequency generator, placed outside the home, that produces a sound above human hearing, at the 40-kHz frequency range. Dogs and cats can hear the noise, but humans cannot. The other part of the tool includes a receiver, also tuned to 40 kHz. Attached to the receiver is a digital module that can both visually and audibly confirm the intensity of the air leak.
The audible portion of the reading is heard through a set of headphones. The visual reading is presented in either decibels or on a linear scale. In either case, the higher the reading, the larger the air leak. The manufacturer claims that leaks as small as 0.06 mm (0.002 in.), about half the width of a human hair, can be detected by the equipment.
The great thing about this technology is that a single building component can be tested without the need to set up blower-door equipment or when a building’s air barrier is not complete. It also comes in handy if the indoor and outdoor temperatures are so similar that thermal imaging is ineffective.
This tool is not a replacement for a blower door, but I am so impressed with its operation that I’m adding it to my energy auditing and building diagnostic toolbox. The Portascanner comes in two models: The standard model only detects air leaks, while the Portascanner Airtight can estimate air-leakage rate for isolated locations.
These tools are not cheap—the standard Portascanner is $4083 and the Portascanner Airtight is $12,000—but they are unique in their capabilities. You can find more information at coltraco.com and at the U.S. distributor, Source 2050 (source2050.com).
— Randy Williams; home energy auditor and contractor in Grand Rapids, Minn. Photos courtesy of the manufacturer.
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- How to Find Air Leaks in Your House
- Straightforward Air-Sealing Strategies
- Fix Air Leaks in Old Houses
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