Energy Audit vs Retro Commissioning: Which Does Your Building Need?
We see it all the time. Building owners are aware of their building’s inefficiencies, but they don’t know how to fix them. It can get confusing.
Should you start with a commercial energy audit?
Or does your building need retro-commissioning services?
The answer depends on the problem you are trying to solve.
An energy audit simply tells you what to fix. Retro-commissioning—often called RCx—focuses on applying upgrades to your building based on said audit’s recommendations. Both are valuable tools for building performance improvement, but they are different.
Some buildings need an audit first. Others need RCx. Many need both.
Understanding the difference between an energy audit vs retro commissioning can help building owners make better decisions, avoid unnecessary capital spending, and stay ahead of energy compliance requirements.
What Is an Energy Audit?
A commercial energy audit is a structured evaluation of how a building uses energy. The goal is to identify opportunities to reduce energy consumption, improve performance, and identify which upgrades are necessary.
During an energy audit, an energy professional reviews utility data, evaluates major building systems, and identifies energy conservation measures. These measures may include operational changes, equipment upgrades, lighting improvements, building envelope improvements, HVAC upgrades, or controls adjustments.
Depending on the level of detail, an energy audit may include:
Utility bill analysis
Building walkthroughs
HVAC system review
Lighting system review
Controls evaluation
Energy conservation measure recommendations
Cost and savings estimates
Simple payback calculations
Energy audits are especially useful when a building owner needs a broad understanding of where energy is being used and which improvements may offer the best return.
In simple terms, an energy audit answers:
Where is the building wasting energy, and what improvements should we consider?
What Is Retro-Commissioning?
Retro-commissioning, on the other hand, is the process of improving how existing building systems operate. Instead of solely on what should be replaced or upgraded, RCx also focuses on whether current systems are working as intended.
Many buildings drift away from optimal performance over time. Schedules get changed. Control sequences are overridden. Sensors fail. Tenants change.
The building may still “work,” but it may not be efficient.
Retro-commissioning looks for those operational problems and corrects them.
Typical RCx measures may include:
Adjusting HVAC schedules
Correcting control sequences
Calibrating sensors
Optimizing economizer operation
Reducing simultaneous heating and cooling
Improving start/stop schedules
Resetting supply air temperature or static pressure strategies
Verifying equipment operation
RCx is often one of the most cost-effective ways to improve building performance because it focuses on optimizing systems that are already installed.
In simple terms, retro-commissioning answers:
Are the building’s existing systems operating the way they should?
When an Energy Audit Is the Better Starting Point
An energy audit is usually the better starting point when the building owner needs a broad understanding of performance and improvement opportunities.
You may need a commercial energy audit if:
You do not know why utility costs are high
You need a prioritized list of energy improvements
You are planning capital upgrades
You need cost and savings estimates
You are evaluating multiple building systems
Your building is subject to an energy audit requirement
Benchmarking results show poor performance
Ownership needs a business case for improvements
Energy audits are particularly useful when owners need a map.
For example, a building owner may know the property has high energy use, but not whether the issue is HVAC, lighting, controls, tenant load, poor scheduling, or outdated equipment. An audit helps organize the problem and identify the most practical next steps.
A good audit should do more than point out deficiencies. It should also help owners understand which improvements are worth pursuing, which should be delayed, and which require further analysis.
When Retro-Commissioning Is the Better Starting Point
Retro-commissioning is often the better starting point when the building’s systems are generally in place, but performance seems off.
You may need RCx if:
HVAC systems run longer than necessary
Energy use stays high overnight or on weekends
Controls are outdated, overridden, or poorly sequenced
Tenants report comfort issues
Equipment appears to be fighting itself
The building has a building automation system, but no one has reviewed the sequences recently
Utility data suggests operational waste
The building has not been tuned in several years
RCx is often valuable for buildings that are not necessarily old or poorly equipped. Even newer buildings can underperform if controls are not configured correctly or if operations no longer match actual occupancy.
This is where many building owners miss an opportunity. They assume improving performance requires replacing equipment, when the first step may be making sure existing equipment is operating correctly.
Before spending capital on new systems, RCx can help answer:
Are we getting the best performance from what we already have?
When Compliance Programs Require Both
Across many cities, energy compliance programs and building performance standards use both audits and retro-commissioning as part of their compliance structure.
Some jurisdictions require building owners to benchmark energy use annually. Others require periodic energy audits, retro-commissioning, or performance improvements if buildings do not meet certain thresholds.
In these cases, the audit and RCx serve different compliance purposes.
An audit may be required to identify energy conservation measures and document potential improvements. RCx may be required to verify and optimize the performance of existing systems.
For example, a compliance program may require a building owner to:
Benchmark annual energy use
Determine whether the building meets a performance target
Complete an energy audit if the building underperforms
Perform retro-commissioning to optimize systems
Implement required improvements or submit documentation
This is why building owners should not treat energy audits and RCx as interchangeable. One may satisfy part of a requirement while the other addresses a different part of the compliance pathway. Under our Energy Compliance Page, you can find out what your city’s regulations are, and if we service your area.
How to Decide Which Service Your Building Needs
The best starting point depends on what you already know.
If you do not know where the problem is, start with an energy audit.
If you suspect the problem is how systems are operating, start with retro-commissioning.
If your building is facing a compliance deadline, review the ordinance or program requirements carefully. Some programs specify exactly which service is required and when.
Here is a simple decision framework:
Start with an energy audit if:
You need a full building assessment
You need project recommendations
You need cost and payback estimates
You are planning capital improvements
You need compliance documentation
Start with retro-commissioning if:
Systems are running outside expected schedules
Controls appear misaligned
Occupants report comfort problems
Energy use is high during unoccupied periods
You want to optimize existing systems before replacing equipment
Consider both if:
The building has not been reviewed in years
Benchmarking shows underperformance
You need both recommendations and operational corrections
You are preparing for a building performance standard
You want a long-term building performance improvement strategy
Why the Distinction Matters
Choosing the wrong service can waste time and money.
If you order an audit when the building really needs RCx, you may end up with a report that identifies issues but does not correct the operational problems driving waste.
If you start with RCx when the building needs major upgrades, you may optimize systems that are fundamentally outdated or inefficient.
The best approach is not always either-or. It is often sequential.
A building may begin with a commercial energy audit to understand the full opportunity, then move into retro-commissioning to correct operational issues, then use the findings to guide capital planning.
How IE Energy Helps
By evaluating building energy data, operating conditions, compliance requirements, and system performance, we can recommend the right starting point. We help owners avoid unnecessary work, prioritize practical improvements, and develop a clear path toward better building performance.
Whether your building needs a full audit, an RCx process, or a combined strategy, IE Energy can help you understand the right next step.
