October 25, 2022


A properly pressurized building is very important in Florida; especially with its tropical environment which can play havoc with the indoor environment of the building. One way to ensure the quality of the building environment and pressurization is to directly monitor the outside air flow rate.

The outside air monitor can be a big part of how a building performs; but installation issues along with location issues plague not only the test and balance firms, but the performance of the building. Although pressurization is not the sole source of moisture issues or indoor air quality issues, it is a major cause of the “M” word-mold.

Most manufacturers have installation guidelines to ensure minimum duct diameters are met on the front and back side of the monitor for proper operation. When these guidelines are followed, not only does the monitor function properly, all test and balance firms can calibrate and validate air flows.


Also, let’s not forget roof top units with outside air intakes, location and accessibility is just as important in order to test and set. Here we have included pictures of a recent project which is an example of why TAB firms have problems accurately setting the outside air. Multiple problems for the TAB firm service personnel are:

  • Accessibility to test outside air
  • No access to the motorized damper to adjust settings.
  • Roof line and gutter route rain water to the top of intake.

Properly placed and installed monitors and intakes lower your start-up, maintenance cost, reduce energy consumption and improve control of the HVAC system.