What is measured and adjusted
- Supply, return, fresh-air and exhaust airflow of the unit.
- Flow at each diffuser, grille or terminal, and branch damper settings.
- Duct pressures, filter and coil pressure drops.
- Fan speed (drive), pressure or flow set points.
- Heating and cooling coils: water flows, together with hydronic balancing.
How AHU commissioning is carried out
- Preliminary checks: new filters, belts or motors, rotation, dampers and fire dampers open.
- Total airflow measured at the fan (Pitot traverse in the duct or fan pressure tapping).
- Balancing of branches then terminals, to the tolerance set in the specification.
- Control set points and tests: temperatures, pressure, variable air volume, operating modes.
- Air balancing report and unit commissioning sheet.
Acceptance references
Standard EN 12599 describes test procedures and measurement methods for handing over ventilation and air-conditioning systems. Airflow tolerances are generally set by the project specification. Commissioning companies can also carry out measurements on mechanical smoke-control systems.
Finding an AHU balancing company on Metteur au Point
1. Describe the project
Post a free project request: building type, systems involved (AHUs, supply and return ductwork), drawings and specifications if you have them, timescale.
2. Network companies reply
Interested commissioning companies send you an anonymous quote to compare on substance: method, measuring equipment, timescale, price.
3. You choose, no commission
Accept the quote that suits you and then work directly with the chosen company. No commission on the job.
Companies by city
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Frequently asked questions
What is the difference between ventilation balancing and AHU balancing?
Extract ventilation removes air (and supplies it in heat-recovery systems) at regulatory rates per room. An AHU treats air (filtering, heating, cooling, humidity) and distributes it through more complex ductwork, with controls to set at the same time as the flows.
Is balancing a VAV system different?
Yes: VAV boxes must be set to their minimum and maximum flows, then the fan pressure set point adjusted, and system behaviour checked at part load.
How much does AHU balancing cost?
It depends on the number of terminals, access to ducts and ceilings, and the control tests required. Post a project request to receive comparable quotes.
See also
An AHU to commission?
Describe the units and ductwork: the network’s balancing companies send you their quotes, with no commission.