What’s the Difference Between a Commercial Building Energy Audit and Retro-Commissioning?

There are many tools of the trade in the world of building energy efficiency. Knowing the difference between approaches, like the difference between a commercial building energy audit and retro-commissioning, can help you take the next best step to lower your energy bills, while meeting your immediate economic needs. Sometimes you want to simply, inexpensively, lower your operating costs with little investment. In this case RCx is a good fit because you can make the best use of equipment that you’ve already improved upon, running it optimally by paying attention to how you heat and cool, when, and how you’re using what mother nature’s giving you with outside air. But sometimes, you don’t have the infrastructure you need to run your building efficiently – you need to improve your performance and you have some capital available to invest to make your property worth a lot more. You can increase sustainability and increase the building value, occupant comfort and safety. And when you do that, you want to invest in smart options for the future.

Depending on what situation you find yourself in can mean the difference in your approach to an audit, or an RCx project.

What is an energy audit?

An energy audit is an investigation of your building’s energy using systems, including the building envelope and basic assets. The goal is to identify energy saving opportunities/projects, (aka energy efficiency measures or EEMs) in your building. The scope involves only investigation of your building, and no project implementation…that comes later.

Energy audits come in different shapes and sizes defined by levels. The levels for commercial buildings (Level 1, 2 or 3) are defined by The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). ASHRAE published the set of procedures for performing energy audits and a standard defining each level’s contents (both co-authored by kW’s President, Jim Kelsey).

How do you get the most value out of your energy audit?

To find out more about the commercial building energy audit process, and what should be included in the report, check out our post on getting the most value from your ASHRAE energy audit. When you’re ready to find a qualified and experienced energy auditor, check out our post on how to hire and energy auditor for tips.

What is retro-commissioning?

Retro-commissioning (or RCx) refers to a process that involves investigating a building’s equipment, systems and current occupancy together to understand and improve their operation. Systems can become inefficient due to changes in equipment operation, response to ambient conditions or changes in the way the building is used. RCx focuses more on examining operation of building systems, using logged data, onsite observations, design review and analysis to look for energy savings opportunities. In short, RCx uses labor and smarts to find opportunities to run the building you have at its most optimal, while energy audits focus on what investments might make your overall operation the best – in terms of suitability for the task, daylight, comfort, safety and productivity.

How do you know if it’s time to perform retro-commissioning?

Not all buildings are good candidates for retro-commissioning. Check out our post identifying the top 5 signs your building is ready for RCx.

What’s the difference between commissioning, re-commissioning and retro-commissioning?

Both commissioning and re-commissioning typically require going through and testing all the sequences of operation for the HVAC and lighting systems. Commissioning is a process which applies to new construction to ensure the building operates as designed. Re-commissioning applies to existing buildings and I take it to mean returning a building to a prior design intent. Retro-commissioning focuses on updating control sequences to find the best marriage between the building you have, and the way that its currently used. We tailor the best solution for your building by examining trend logs and applying our own fault detection algorithms to look for problem spots at your site using data from your BAS, or short-term loggers. You can learn more about the differences between these processes in this post.

Do I need an energy audit or retro-commissioning?

Unfortunately, there’s no one right answer because (Engineer’s favorite answer here); it depends. All buildings are different and so are the economic pressures on a property’s ownership. Sometimes you need to do the best with what you have – that’s RCx. Sometimes you have an opportunity to invest for a more efficient future, and reap the economic rewards later – that’ when you want an audit, a plan for the future that can be the best way to increase the value of your property in the long haul.

If you would like to discuss your options for lowering your energy bills, increasing building sustainability or performance, contact us anytime.

Scroll to Top