Even if you’ve never laid hands on one, the term “thermal camera” is pretty much common knowledge. An acoustic camera, however, is a new concept to many. We’ve asked our Global Business Development manager, Daniel Gyorev, to break down both concepts, and draw some comparisons in this Thermal vs acoustic camera blog.

Daniel, can you tell us how an acoustic camera works?

To grasp how an acoustic camera works, let’s first delve into the mechanics of a thermal camera. A thermal camera measures the heat, also known as infrared radiation, emitted by objects, transforming this thermal energy into a visible image. The key component of a thermal imaging camera is its infrared sensor, also known as a thermal detector or microbolometer, finely tuned to detect radiation within a specific wavelength range. The infrared sensor is made up of an array of thousands of individual detectors, each of which measures thermal emission. The camera then processes this data to create a thermal image, with each pixel representing a specific temperature value.

Ok, so does an acoustic camera do the same only then with sound? 

An acoustic camera functions through the integration of an array of strategically positioned microphones, sophisticated signal processing, and visualization techniques, culminating in a visual representation of sound sources. These microphones are arranged geometrically to capture sound waves emanating from various directions. Recording both the arrival time and amplitude of sound waves, the microphones enable the calculation of time differences, thereby pinpointing the precise location of a sound source. The acoustic camera processes this data to generate an acoustic image, presenting a heat map. This heat map provides a comprehensive depiction of the direction and intensity of the detected sound sources.

How are a thermal and acoustic camera used in the building industry?

Both thermal imager and acoustic camera find numerous valuable applications in the building industry. Some typical applications include:

• Energy efficiency assessment
• Building envelope inspections
• Quality control in construction
• Building preservation

– Energy efficiency assessment

Thermal imaging comes into play to detect areas of heat loss or air leakage in buildings. By precisely locating poorly insulated spots or gaps in doors and windows, building professionals can make informed decisions to enhance energy efficiency. On the other hand, an acoustic camera is adept at spotting sound leaks, and where there’s a sound leak, there’s an air leak. Consequently, minimizing sound leaks is directly tied to improving the airtightness and overall energy efficiency of a building. So in terms of thermal vs acoustic camera, the acoustics have the upper hand in this example.

– Building envelope inspections

Both a thermal imager and an acoustic camera can be used to evaluate the performance of a building’s envelope, which includes walls, windows, doors, and the facade. They aid in pinpointing areas where insulation is deficient or compromised.

– Quality control in construction

In construction and renovation, thermal and acoustic imaging can be used to ensure that new installations, like insulation, are installed correctly, without any gaps or defects.

– Building preservation

Both thermal and acoustic imaging can be used to evaluate the condition of walls, ceilings, and other structures without resorting to invasive measures, thereby aiding in the preservation of the building’s integrity.

What does the measurement setup look like?

A thermal imager is typically used in conjunction with blower door test equipment — a specialized fan temporarily installed in a building’s doorway. This setup blows air out of the building, generating negative pressure. If there are air leaks, such as gaps in insulation or cracks in the building’s envelope, the thermal imager will expose them.

An acoustic camera is usually used in combination with an omnidirectional speaker — a speaker that emits sound in all directions simultaneously, creating a 360-degree sound field. If there are sound leaks, such as gaps in insulation or cracks in the building’s envelope, the acoustic camera will expose them.

Are there any advantages to using an acoustic camera

To operate an acoustic camera, you need to generate white or pink noise from an omnidirectional speaker, which is much more convenient and quicker than installing a blower door fan.

Unlike a thermal imager, with an acoustic camera, you aren’t reliant on the weather and sunlight. You can conduct measurements at any time.

An acoustic camera can provide a higher level of precision in detecting leaks from small cracks and gaps.

So an acoustic camera is easier to use and more precise?

Yes! But, a thermal imager can detect leakage through the structure, while an acoustic camera can only detect airborne leaks.

Conclusion

Both thermal and acoustic cameras are able to visualize leaks in buildings, allowing you to make a more sound and energy efficient construction. The measuring process with an acoustic camera is much less dependent on external factors, such as the weather. Making it much easier and quicker to perform consistent measurements.

It is however important to understand the type of leak you are trying to find. Are you looking for actual cracks that leak sound and air through the wall, an acoustic camera is your weapon of choice. If you are trying to understand how heat or air is travelling through the structure, a thermal camera will give you the answers you are looking for.

To conclude the battle of thermal vs acoustic camera, both camera’s will visualize airstreams in walls that are otherwise invisible and undetectable. The type of stream (airborn or instructural leaks) you are trying to detect, determines the device that will help you the best.

An acoustic camera, like our Sorama CAM iV64, allows you to do measurements at any time of the day, regardless of the environment or weather conditions. The device is portable and easy to use in the field, so doing measurements is literally a breeze.  This is why we favor the technology of an acoustic camera and have developed applications to support you in optimizing your livable buildings.