HVAC Testing, Adjusting, and Balancing (TAB) Services

Testing, Adjusting, and Balancing, commonly referred to as TAB, is the systematic process of measuring, evaluating, and adjusting HVAC systems to ensure they operate in accordance with the original design intent. For commercial buildings, proper TAB is not an optional step. It is the final verification that a mechanical system performs as engineered and delivers conditioned air, ventilation, and hydronic flow to every zone of a building at the specified rates.

Without TAB, even a well-designed and properly installed HVAC system may fall short of its performance targets. Airflows may be unbalanced, zones may be over- or under-conditioned, and energy consumption may exceed projections, often with no obvious indicator during routine operation. TAB identifies and corrects these deficiencies before they become long-term problems.

MGM Associates provides certified HVAC testing, adjusting, and balancing services for commercial, institutional, and industrial facilities throughout North Alabama and the Tennessee Valley. Our technicians work from design documentation and use calibrated instrumentation to verify that each system component delivers what the mechanical engineer specified: air-handling units, terminal devices, pumps, coils, and distribution networks alike.

What Is HVAC Testing, Adjusting, and Balancing?

TAB is a structured field process carried out after HVAC installation is complete. Technicians begin by reviewing the mechanical design documents (system schematics, equipment schedules, and airflow diagrams) to understand what each system is intended to deliver. They then measure actual conditions in the field using calibrated instruments and compare those readings to the design values.

For air systems, this includes measuring supply, return, and exhaust airflows at every terminal device in the building, as well as evaluating fan performance, static pressure, and duct distribution. Dampers and variable volume devices are adjusted until each zone receives the correct volume of conditioned or ventilation air specified in the design. The process accounts for supply and return air in every occupied space, ensuring the system meets both comfort and ventilation code requirements.

Hydronic systems receive the same level of attention. Water flow rates through heating and cooling coils, pumps, heat exchangers, and terminal units are measured and adjusted to match design flow rates. Pressure differentials across critical components are verified. Improper hydronic balance can result in some zones being unable to reach setpoint temperatures regardless of how the controls are configured. Proper TAB resolves this at the system level.

The final output of the TAB process is a comprehensive certified report documenting all measured values alongside design targets. This report provides engineers, contractors, building owners, and commissioning agents with a clear record of system performance at turnover.

Why TAB Is Critical for Commercial HVAC Systems

The relationship between HVAC performance and building operations is direct. Systems that are not properly balanced consume more energy, create occupant comfort complaints, and degrade faster than systems that have been verified against their design parameters. TAB is the mechanism that closes the gap between design intent and actual performance.

In facilities that require documented system performance (hospitals, laboratories, government buildings, and LEED-certified projects) TAB is not optional. Specifications on these projects typically require certified TAB by a NEBB- or AABC-certified firm, and the results must be submitted as part of the project closeout package. Even on projects without explicit contractual requirements, TAB protects every party involved: the engineer of record, the mechanical contractor, and the building owner.

Benefits of proper HVAC testing and balancing include:

Verified airflow delivery to all occupied zones, reducing comfort complaints
Reduced energy consumption through properly adjusted fan speeds, pump curves, and damper positions
Compliance with ventilation requirements under ASHRAE 62.1 and applicable building codes
Documentation of system performance for warranty, commissioning, and operations purposes
Early identification of equipment deficiencies, installation errors, or design discrepancies
Extended equipment life through correct operating conditions and reduced strain on mechanical components
A reliable baseline for future troubleshooting and recommissioning

Our HVAC Testing and Balancing Services

Air Balancing

Air balancing is the core of most TAB scopes. Our technicians measure supply, return, and exhaust airflow at every terminal device (diffusers, grilles, registers, VAV boxes, fan coil units, and exhaust fans) using calibrated instruments including pitot tube arrays, flow hoods, and digital manometers. Readings are compared to design values, and devices are adjusted until the system is in balance.

Air balancing also includes verification of air-handling unit performance: fan total static pressure, motor amperage, supply and return fan airflows, and outside air quantities. Where variable air volume systems are present, controls sequencing is verified in coordination with the controls contractor to confirm proper operation across the full range of system loads.

Hydronic Balancing

Hydronic systems, including chilled water, heating hot water, condenser water, and domestic water loops, require precise flow balancing to deliver the correct capacity to each terminal unit. MGM Associates measures flow rates using calibrated ultrasonic flow meters and differential pressure gauges, adjusting balancing valves and verifying pump operating points against published curves.

A hydronic system that is out of balance may deliver adequate total system flow while individual coils and terminal units receive too much or too little, resulting in unmet loads and comfort complaints that control adjustments alone cannot resolve. Proper hydronic balancing ensures each branch circuit receives its design flow and that the primary and secondary loops operate as intended.

HVAC Commissioning Support

TAB and commissioning are closely related but distinct activities. TAB verifies that systems are balanced and operating at design conditions. Commissioning verifies that systems operate correctly across the full range of intended modes and sequences. MGM Associates works closely with commissioning agents throughout the construction process to ensure that balanced systems are ready for functional performance testing.

Our TAB reports provide commissioning agents with the documented baseline data they require to conduct their work efficiently. We coordinate with controls contractors, mechanical contractors, and the commissioning authority to ensure that testing sequences are completed in the correct order and that any deficiencies identified during TAB are resolved before formal commissioning activities begin.

Industries We Serve

Healthcare Facilities

Hospitals, surgical centers, and clinical facilities operate under strict ventilation and pressurization requirements governed by ASHRAE 170 and FGI Guidelines. Correct air change rates, directional airflow between clean and contaminated spaces, and documented system performance are mandatory, not optional. TAB in healthcare settings requires precision, thorough documentation, and coordination with infection control protocols.

Universities and Schools

Educational facilities, from K-12 schools to university research buildings, present a wide range of HVAC complexity. Classrooms require consistent ventilation to support occupant health and cognitive performance. Laboratories, gyms, and auditoriums each carry unique airflow requirements. Proper TAB ensures each space receives adequate ventilation regardless of the diversity of occupancy types within a single building.

Government Buildings

Federal and state government construction projects frequently require NEBB-certified TAB as a contract specification. These projects demand thorough documentation and strict adherence to design parameters. MGM Associates has experience working on government facilities with the reporting requirements and site protocols that federal and state projects involve.

Industrial Facilities

Manufacturing plants and industrial facilities often include process ventilation, make-up air systems, and exhaust systems that must be precisely coordinated to maintain safe working conditions and protect equipment. TAB for industrial applications requires an understanding of process requirements alongside standard HVAC performance criteria.

Commercial Office Buildings

Open-plan offices, conference rooms, server rooms, and mixed-use commercial spaces each have distinct HVAC demands within the same building envelope. Balancing these competing requirements while maintaining energy efficiency requires systematic testing and adjustment across the full HVAC system, from the central plant to the individual diffuser in each office.

Our TAB Process

Our process follows NEBB procedural standards for testing, adjusting, and balancing. Each project is approached systematically to ensure thorough coverage and accurate reporting.

System Evaluation. Prior to field work, our team reviews the mechanical design documents, equipment submittals, and project specifications. We confirm that systems are complete and ready for TAB before mobilizing, and we coordinate with the mechanical contractor on any outstanding installation items.
Airflow Measurement. Using calibrated flow hoods, pitot traverses, and digital instrumentation, we measure airflow at every terminal device and air-handling unit. Initial readings are recorded and compared to design values to establish baseline system conditions.
Hydronic System Testing. Pump operating points are verified against nameplate data and published curves. Flow rates through coils, heat exchangers, and terminal units are measured using ultrasonic or differential pressure methods. Balancing valves are adjusted to achieve design flow distribution throughout the system.
System Adjustments. Dampers, balancing valves, variable frequency drives, and terminal unit controllers are adjusted to bring all system components to within the tolerances specified by NEBB standards and the project specifications. Proportional balancing methods are used to achieve system balance while preserving total system airflow and flow rates.
Final Verification and Reporting. After adjustments are complete, final measurements are taken and recorded. A certified TAB report is prepared documenting all design values, measured values, and final adjusted conditions for every system and terminal device. The report is submitted to the engineer, contractor, and building owner as part of the project closeout package.

Certified Testing and Balancing Professionals

Certification matters in TAB because the accuracy of results depends directly on the training, methodology, and equipment of the technicians performing the work. The two primary certifying bodies for TAB contractors in the United States are the National Environmental Balancing Bureau (NEBB) and the Associated Air Balance Council (AABC). Both organizations establish procedural standards, require the use of calibrated instrumentation, and mandate that certified firms maintain quality assurance programs covering their field operations.

NEBB certification, which MGM Associates holds, requires that a firm demonstrate knowledge of TAB procedures, maintain calibrated field instruments with current calibration records, and employ a certified professional supervisor who is responsible for the technical accuracy of all TAB reports issued by the firm. Project specifications on institutional, government, and large commercial projects frequently name NEBB or AABC certification as a requirement.

Working with a certified TAB firm means that the data in your TAB report is backed by a recognized quality standard, not just the judgment of an individual technician. It also means that the engineer of record, the owner, and the commissioning agent can have confidence in the accuracy of the documented system performance.

Service Area

MGM Associates is based in Guntersville, Alabama, and provides HVAC testing, adjusting, and balancing services throughout North Alabama and the Tennessee Valley. We work with mechanical contractors, general contractors, mechanical engineers, commissioning agents, and facility managers on projects of all sizes across the region.

Our primary service area includes:

Huntsville, Alabama and the surrounding Madison County area
Guntersville and Marshall County
Decatur and the Tennessee Valley corridor
Birmingham and North-Central Alabama
Chattanooga, Tennessee
Nashville, Tennessee and Middle Tennessee

If you are planning a commercial HVAC project in this region and need a certified TAB contractor, contact us early in the construction schedule. Coordinating TAB scope and scheduling during the mechanical coordination phase avoids delays at the end of the project.

Frequently Asked Questions

What is HVAC testing and balancing?

HVAC testing and balancing is the process of measuring, adjusting, and documenting the performance of air and hydronic systems to verify that they operate in accordance with the mechanical design. This includes measuring airflows at all supply, return, and exhaust terminals; verifying fan and pump performance; and adjusting distribution systems until each zone receives the flows specified in the design documents.

When should TAB be performed?

TAB is typically performed after HVAC installation is complete and systems have been started and checked out by the mechanical contractor, but before the building is occupied. For phased construction projects, TAB may be performed in stages as each system is completed. TAB can also be performed on existing buildings as part of a recommissioning effort or when persistent comfort or energy performance problems need to be diagnosed and resolved.

Is TAB required for new construction?

TAB is required on many commercial projects by project specifications, by the authority having jurisdiction, or by certification programs such as LEED. ASHRAE Standard 90.1, which is the basis for energy codes in most states, includes requirements for HVAC system commissioning that encompass TAB activities. Healthcare facilities regulated under FGI Guidelines are subject to specific ventilation verification requirements. Even on projects without an explicit TAB requirement, performing TAB is considered standard practice for quality mechanical construction.

How long does HVAC balancing take?

The duration of a TAB project depends on the size and complexity of the HVAC systems involved. A single-story commercial office building with a straightforward air distribution system may require a few days. A multi-story hospital or university research facility with complex air and hydronic systems may require several weeks of field work. TAB scope and schedule should be discussed during the preconstruction or mechanical coordination phase to ensure adequate time is built into the project schedule.

What problems can TAB solve?

TAB can identify and resolve a range of HVAC performance issues, including hot and cold spots in occupied spaces, excessive energy consumption, inadequate ventilation, noisy duct systems caused by improper airflow velocity, equipment operating outside its design range, and hydronic systems that cannot reach temperature setpoints. Many comfort and performance complaints in commercial buildings have their root cause in an HVAC system that was never properly balanced, a problem that TAB can diagnose and correct systematically.

Request TAB Services

MGM Associates provides NEBB-certified HVAC testing, adjusting, and balancing services for commercial and institutional projects throughout North Alabama and the Tennessee Valley. Whether you are a mechanical contractor scheduling TAB for a new construction project, an engineer coordinating commissioning activities, or a facility manager dealing with a chronic comfort or energy performance problem, we can help.

Contact us to discuss your project requirements, schedule, and TAB scope. We are available to review design documents, provide preliminary scheduling input, and coordinate with your project team from early in the construction process.

Contact MGM Associates