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IR Inspections to Diagnose HVAC Airflow

HVAC systems play an important role in building performance and tenant comfort. Under the right circumstances, an infrared imager can be used to help document and analyze airflow patterns within conditioned spaces.

Infrared imagers are capable of detecting and displaying thermal patterns across the surface of an object. Using an infrared imager to diagnose HVAC airflow problems is a challenge since air does not have a surface. While infrared imagers cannot image air currents directly, they can detect the effect of air currents on building surfaces.

Before attempting to diagnose airflow patterns, one should ensure that the building’s insulation is sound and the HVAC system has been checked for appropriate delta T, clean filters, etc. An infrared imager may then be used within occupied spaces to document thermal patterns associated with airflow.

Due to its graphic nature, thermal imaging can be particularly useful when documenting results for clients. The thermal images below show an air-conditioned church interior. The left image shows the building as found. The right image shows the resulting thermal pattern after blocked air returns were corrected.

When using an infrared imager to troubleshoot airflow or distribution issues, the following steps can serve as a guide:

• Make the HVAC system call for cooling or heating in a given area
• Image supply diffusers and surfaces that are in the path of diffusers such as windows and walls
• Check for air patterns that indicate the throw of the conditioned air

Unexpected thermal patterns should be investigated for cause and adjustments or corrections made as required. Most air diffusers can be adjusted for both volume and direction. In many cases, conditioned air does not wash the walls or windows properly. Sometimes, conditioned air may be found to be blowing on the HVAC controls causing improper cycling of the system.

Tip Provided by:

John Cannamela

InfraredSurvey.com
4504 Magnolia Ridge Drive
Waxhaw, NC 28173
704-200-6367