The Evolution of the Definition of HVAC Efficiency

Sept. 5, 2012
During a recent industry committee webinar, an extended discussion took place that was very significant for the future of the HVAC industry.

During a recent industry committee webinar, an extended discussion took place that was very significant for the future of the HVAC industry. The discussion was centered on defining HVAC efficiency. Initially it was argued that efficiency could only be determined by following HVAC industry design standards. But then it was proposed that without proper installation, the intent of the design could never be met. Then the conversation jumped to a whole new level that took the committee by surprise.

Hugo Aguilar represents a Codes & Standards working group, and provided a passionate update about their efforts to add an effective efficiency layer to the traditional role of health and safety from a code official perspective. He expressed frustration that although their group had been assigned the responsibility to enforce efficiency, no reliable method existed to assure efficiency was being delivered to the end user.

Design Determines Efficiency

Initially the group supported design as the deciding factor of a system’s efficiency. An idea was tossed around that the task of creating Manual J design documents be taken from the contractors and become the duty of a subcontractor hired by the city building departments called “Plan Checkers.”

Soon it became apparent that the design lacked the ability to assure efficiency because the complex nature of field conditions often contradicted the idealistic design proposed on the schematic of a system. Also there’s so much wiggle room in varying design inputs that inspectors may not have the ability to interpret design. The idea was proposed that another professional may then be needed to decipher design intent.

No, Raters Determine Efficiency

The next proposed solution to assuring a system was actually efficient was that the energy raters would verify that actual efficiency existed. It was surprising how short lived that proposed solution lasted in this discussion.

The concept that energy raters could assure efficiency was set aside in only a few minutes. Two primary reasons included: first that only a small percent of retrofit jobs (less than 10%) were currently being rated, even though it’s required by law in California. There’s little hope that this will change. Second, current test methods used by the energy raters provided little assurance that efficiency was truly being delivered to consumers.

For the first time, the idea was raised that energy rating is lacking the complete level of skill needed to provide this assurance and the value to the end consumer was questioned. Rating, as it currently exists, was skipped over and almost dismissed as the answer to assuring HVAC energy efficiency.

Installation Must Determine Efficiency

Then the conversation moved to the idea that the installers were really the ones that controlled efficiency. The quality installation checklists were mentioned, but then also passed by as only an emerging standard. It was determined they lacked the ability to assure efficiency was being delivered and this was never the original intent of the standard.

ASHRAE defended that the standard was incomplete by stating that standards were not intended to dictate the how-to of testing and verifying, only that it should be complied with. The question was raised that additional how-to steps must be required before a checklist approach could ever be relied upon to verify if efficiency was being delivered at all.

Actually, Only Output Can Determine Efficiency

Mel Johnson of Southern California Edison posed a series of careful questions throughout the conversation that contributed to the final outcome of this important and evolutionary discussion. As a long time proponent of the HVAC industry and a leader in the pursuit of efficiency, Mel itemized the efforts of the past and present and summarized the advancements and failures of the industry that California had passed through on its journey towards HVAC efficiency.

It was Hugo that finally spoke the magic word that would paint the picture for opportunities facing HVAC system efficiency: “Output.” Output was the word that capped the discussion and will pave the way for the future. It dominated the remainder of the committee meeting when it came to efficiency. The idea that design, rating and installation would someday all be verified by documenting the output of the system settled in on the committee.

In reality, all other criteria fail to document efficiency except the final operating output of the system once the installation is complete.

Is design essential to final output? Sure, without adequate design there’s no plan that can be followed to achieve the outcome of efficiency.

Are installation practices and checklists mandatory to assure the system is built to the design standards? Absolutely, but they fall short as a verification tool.

Design and installation will fall short of delivering efficiency every time if the output or performance of the system is not tested, adjusted, measured, and verified to meet the specifications the manufacturer has established for the equipment at the completion of the job. Verification must assure that the installation of the electrical, refrigeration, gas and air distribution systems are each working in harmony. Together they deliver the output that’s promised to the end user — the consumer.

Air Balancing and System Commissioning

The reason for my excitement about this discussion is that regulators are finally beginning to understand that after decades of superficial bits and pieces of the efficiency picture being focused on, the true end goal of actual delivered efficiency can be met by measuring operating system output.

This is where the fat lady sings. The definition of HVAC system efficiency has passed through various stages over the past 30 years. Initially it was equipment efficiency, then tight duct systems, then design. There was a jump to the refrigeration circuit as a component of efficiency, and then a grasp at the current trend of installation checklists. The reality is that while each of these is a piece of the efficiency puzzle, individually each fails to provide the result of the system delivering the final output. Measured output does equal efficiency!

This is really just the beginning. We enjoyed a moment where the clouds parted and the light shinned through. It has taken us decades to perfect how output can be measured. While many are beginning to understand that output can be measured in the field, the learning curve for the industry as a whole will still be long and challenging.

Several thousand have paid the price to accurately measure the output of an HVAC system. This is my portion of the world where I’m able to serve this industry. Through careful learning, study and practice, the skills and disciplines have been mastered that enable individuals and companies to measure and rate the installed operating performance of HVAC systems.

Is the playing field level? No, these guys and gals have an extreme advantage over their competitors. They’ve paid the price and earned the right to build the culture in their professions and companies required to have this advantage. Can the rest of the industry catch up? Sure over the years and in time. These skills cannot be imitated or faked. But as the skills and technology used by this group develop, these practitioners will continue to lead the field and maintain their advantage. What they do requires more than most are willing to give and contains far more than what can be legislated at this time.

Will others attempt to jump in and shortcut the process? Sure they will and the odds are that they will mess it up many times before they get it right. Measuring the operating performance or output of an HVAC system requires skills far beyond air balancing alone. The future however is bright for those willing to step up to the plate and add these skills to what they offer their customers today.

Rob “Doc” Falke serves the industry as president of National Comfort Institute an HVAC based training company and membership organization. If you're an HVAC contractor or technician interested in a free procedure on hot to measured operating system airflow, contact Doc at [email protected] or call him at 800-633-7058. Go to NCI’s website at for free information, articles and downloads.

About the Author

Rob 'Doc' Falke | President

Rob “Doc” Falke serves the industry as president of National Comfort Institute an HVAC-based training company and membership organization. If you're an HVAC contractor or technician  interested in a building pressure measurement procedure, contact Doc at [email protected]  or call him at 800-633-7058. Go to NCI’s website at for free information, articles and downloads.