Guide to Building Commissioning

Building Commissioning is growing as a professional specialist service as it is becoming more widely appreciated that buildings delivered according to their owner project requirements are likely to have fewer design and construction changes, be more energy efficient, and have reduced operation and maintenance (O&M) costs.

The Building Commissioning Association (BCA) membership has grown from 500 in 2005 to over 2,000 today. It reports that interest in their certification program has risen by 30%. This article will explain the basics of building commissioning for the benefit of contractors, architects, and property owners and it will show why this growth should be so.

What is Building Commissioning?

ASHRAE Standard 202-2013, The Commissioning Process for Buildings and Systems, and ASHRAE Guideline 0, The Commissioning Process define commissioning as:

"A quality-focused process for enhancing the delivery of a project. The process focuses upon verifying and documenting that all of the commissioned systems and assemblies are planned, designed, installed, tested, operated and maintained to meet the Owner's Project Requirements (OPR)."

Commissioning (Cx) ensures building quality by using design review and in-field or on-site verification to help maximize energy efficiency, environmental health, and occupant comfort. The process improves indoor air quality by ensuring building components work correctly and that plans are implemented efficiently and effectively. Commissioning also confirms that maintenance plans, O&M manuals, and training procedures are correct and in-place for maintenance staff to follow.

Essentially, the goal of commissioning any project is to ensure that a clear mission is defined for the building and that the building works as intended to fulfill that mission. The most commonly commissioned systems are:

  • heating, ventilation, air-conditioning (HVAC) systems and controls
  • electrical power and lighting systems
  • gas systems (natural gas, laboratory gas, medical gas, etc.)
  • domestic hot water systems
  • renewable energy (solar photovoltaic, geothermal, wind, etc.) systems
  • façade systems

Why is Commissioning Useful?

The National Institute of Building Sciences (NIBS) describes how Cx can assist in the delivery of a high-quality and robust building project: one that provides a safe and healthy facility with reduced energy use, reduced operating cost, adequate O&M staff training, and improved building systems documentation.

The key drivers of Cx are energy cost reduction, sustainability, reduced O&M costs, improved efficiency, and occupant health and safety, but these may vary according to building type and owner.

Reduced Operating and Maintenance Costs

Operating cost reduction is now prevalent as businesses seek to reduce waste to stay competitive. Cx can help property owners ensure they achieve the best returns possible from the capital invested in building systems.

There are important studies that demonstrate that commissioning returns even more financially if efficient and cost-effective maintenance is carried out.

Improved Efficiency

Cx and its variants are good ways to ensure building systems operate efficiently and effectively. Systems that perform efficiently require less energy (i.e. reduced energy use intensity), which reduces energy costs. Efficient systems also require less maintenance, which also reduces costs to a company.

An often overlooked efficiency that is gained through commissioning is employee efficiency. When employees are comfortable they tend to be more get more work done with fewer resources. Making sure that employees have comfortable temperatures and lighting conditions will increase worker efficiency.


In addition to energy efficiency and whole-building performance drivers, a key driver for Cx is sustainability and the desire to achieve certification through building performance rating systems such as the US Green Building Council (USGBC) Leadership in Energy & Environmental Design (LEED) rating system. Commissioning has existed for years, but this system has increased its visibility and demand for Cx services.

The LEED New Construction, Commercial Interiors, and Shell and Core rating systems include Fundamental Commissioning as a prerequisite that is required for any certification project. Additional LEED points are available for Enhanced Commissioning, where a Commissioning Agent (CxP) is involved in the process earlier and when issues are revisited post-completion.

Commissioning plays an even larger role in the Building Operations + Maintenance rating system, which includes points for Ongoing Commissioning or Continuous Commissioning with the intent of making periodic adjustments to the building systems so that they continue to operate efficiently.

Other Types of Building Commissioning


Commissioning in an existing building is considered re-commissioning if the building systems had previously been commissioned when construction was completed.

It is known to provide benefits as operating conditions and practices can change over time due to change of equipment and operating staff.

Retro-commissioning (RCx)

Retro-commissioning (RCx) is performed if a building has never been commissioned before. It is a systematic process for identifying underperformance in equipment, lighting and control systems and then performing necessary adjustments. Retro-commissioning focuses on improving the efficiency and extending the life of existing facilities and may involve replacing outdated equipment that isn’t performing to specifications.

Financial support for retro-commissioning is often provided by energy efficiency programs run by utilities or state agencies. Cost-shared assistance for retro-commissioning investigations and free retro-commissioning analysis may be available. Incentives may be paid directly to customers based on achieved annual energy savings.

Ongoing / Continuous Commissioning (automated, monitoring-based, data-based Cx)

Ongoing or Continuous Cx is based on the ongoing collection and analysis of energy data often supplied by an existing Building Automation System (BAS), a Building Energy Management system (BEMS), or via dedicated meters and sensors. Continuous commissioning aims to reduce the numbers of errors being made and to improve reporting and analysis capabilities.

Automating collection procedures is important in making continuous commissioning cost effective. There may be an increased initial cost to set up the procedures, but the benefit of receiving continuous data is that poor performance can be caught and fixed quickly.

Facade Commissioning (Building Enclosure Cx)

Facade Cx (Building Enclosure Cx) refers to building envelope and façade commissioning, a process that examines the robustness of façade elements and their interrelationships. It is important to test the major façade components, but it’s even more important to test the joints between two different components because failures often occur where different systems meet.

Elements and joints that are often tested include, but are not limited to, roofs, windows, curtain walls, flashing, waterproofing, cladding, foundations, terraces, and even plaza elements.

The Role of the Commissioning Agent

Commissioning requires a multi-disciplinary effort involving owners, design professionals, construction managers, and commissioning agents to achieve the best results from the commissioning process.

Commissioning agents (CxA) should be part of the project from the early design phases all the way through the end of the project. They will review the construction documents, comment on the construction submittals, and review construction in the field. They will also participate in the close-out process to ensure that proper documentation exists and that building operations staff have received training. If on-going commissioning is part of the contract, they will stay on for the life of a building.

A commissioning authority or commissioning agent (CxA) is usually contracted directly to a building owner as an independent representative to ensure unbiased performance of the CxA and to confirm that staff members receive site-specific and relevant training.

The BCA now offers 3 certifications for commissioning agents to become either a Certified Commissioning Professional (CCP), an Associate Commissioning Professional (ACP), or a Certified Commissioning Firm (CCF).

The Commissioning Process

Commissioning teams should follow the process given in American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 202-2013 and their Guideline 0-2013, as adopted by the BCA and NIBS.

Cx documentation serves as a record of key team decisions throughout the planning, design, construction, and delivery process. Within it, building system performance standards are described for later verification.

Proper documentation includes the following:

  • The Owner's Project Requirements (OPR)
  • The Basis of Design (BOD)
  • The Commissioning Plan
  • Functional Test Set
  • The O&M Systems Manual
  • Training Document Set
  • The Final Commissioning Report

The two critical documents that architects and owners will develop (and adhere to) during the design phase of a project are explained here.

Owner’s Project Requirements (OPR)

The OPR defines the expectations, goals, benchmarks, and success criteria for the project. It must be developed with significant owner input and meet their approval. The CxA typically assists the owner in identifying the facility's requirements regarding such issues as energy efficiency, indoor environment, staff training, and operations & maintenance. An effective OPR integrates early input from the owner, design team, operations & maintenance staff, and end users of the building. The owner’s project requirements can, and often do, change so it is updated throughout the project.

Basis of Design (BOD)

BOD is a term used to describe project design documentation including written narratives, preliminary drawings, calculations, specifications, and the like. BOD documentation shows how a design meets the operational and performance requirements of a project and its systems. Together, this information tells the story for how the design team has translated the OPR into an actual design. It is an important document as the project transitions into operations because it provides the design thinking and history so that the operations staff understands how the architect and engineers intended the systems to operate.

Commissioning Activities During Each Project Phase

Diagram of Building Commissioning Activity by Phase
Building Commissioning Activity by Phase

According to ASHRAE Guideline 0 (The Commissioning Process) the phases of commissioning cover the Pre-Design, Design, Construction, and Operations & Maintenance phases. As you can see in the diagram above and the descriptions below, we broke out Building Start-Up since this is the time when the systems are put through rigorous testing.

Pre-Design phase:

It is important to start the commissioning process in the project planning or pre-design phase. Early involvement is critical for timely and useful development of the OPR, BOD, the Commissioning Plan, and the beginning of the O&M Systems Manual. If these tasks are left until later and "reverse engineered" to match the design, their usefulness as catalysts for improving early design studies is lost.

Appointing the commissioning agent at the start of the project allows the CxA to become familiar with programming documents so they can proceed immediately to development of the OPR to match the project needs.

Design and Construction phases:

Throughout the design and construction phases, the project team uses the pre-design commissioning documents under the leadership of the CxA to ensure that systems are designed, installed, tested, and are maintainable through the life of the project. The commissioning agent provides the owner with another set of eyes in the field to help ensure a successful building project.

Building Start-Up:

The Start-Up phase is sometimes referred to as the Acceptance phase. The commissioning agent will observe start-ups for each building system and confirm that the design criteria is met. They will review the O&M Systems Manual and training documents to, once again, verify that they properly represent the design intent for each system.

Upon turnover, a building is in the hands of the owner and operators. Although a project is considered complete, some commissioning tasks may continue throughout a typical one-year warranty period. Especially important, is to consider seasonal testing since the building needs to be commissioned during both the heating and cooling seasons to make sure all systems function correctly.

Operations & Maintenance:

After the Startup or Acceptance phase, the commissioning agent provides all documentation to the owner for their use. They may also review the building just before warranty expiration to make sure all systems continue to perform as designed. These activities may be referred to as the Post-Acceptance phase, but ASHRAE defines this as the O&M phase.


Building Commissioning is not a new subject – it stems from the traditional activities of an architect and engineers throughout pre-design, design, construction and building start-up – but it has developed into a standalone professional specialization that is now certifiable.

The complexity and proliferation of technological building equipment and systems has led to the need for a number of commissioning types and applications. A key driver for the growth of commissioning activities is sustainability, which focuses on occupant comfort and energy use reduction. Ensuring that the systems and equipment are installed and function properly will pay for itself many times over through the lower utility bills and increased occupant efficiency.

Article Updated: February 27, 2022
  • Mary Bon

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