When I was a kid, a mouse was a dirty little rodent in the garage that needed to die. Today, it is a sleek little tool on my desk I use several hundred times a day to get work done. Definitions often change. It appears the time has come for the definition of an Efficient HVAC System Installation to change as well.
Traditional Definition of an Efficient HVAC System
I serve with a noble group of industry leaders on a Commercial Installation Committee for the Western HVAC Performance Alliance. A recent meeting focused on an assignment we received from the executive committee: “Define an Efficient Commercial Installation.” Let’s take a look at what we learned as we began to craft this new definition for the industry.
We began work on redefining an efficient installation by evaluating how it was defined in the past. We considered the words of David Boorstin: “Trying to plan for the future without knowing the past is like trying to plant cut flowers.”
Here is the “root” of how the industry currently describes installation efficiency:
• High equipment efficiency ratings
• Design elements are documented
• Installed according to manufacturer’s instructions: electrical, wire and pipe sizing, refrigerant charge, combustion adjustment, adequate venting requirements, and safety controls assuring safe operation
• Licensing, technician training, and acceptable business operations are assured
• Installed to meet code requirements.
Generally speaking, if these elements are complied with, the prevailing belief is installed efficiency will be high and quality has been achieved.
Unfortunately, using this criteria, the typical HVAC system delivers less than 60% of its rated capacity into the building. If consumers knew this fact, heads would begin to roll in Washington D.C.
Time for This Definition to Change
While each of these principles apply to an efficient installation, the committee agreed, based on field data received, that these more traditional elements of efficiency may be included but the system installation often operates at a very low efficiency.
In fact, the traditional definition of an efficient installation has little or no documentable evidence quantifying actual installed efficiency at all. Except for the idea that at one time a prototype of the equipment earned an efficiency rating in a laboratory.
As the discussion continued, we all realized together that our industry has no provision to quantify or score the level of efficiency earned by the installation. “How has our industry gotten away without an installation efficiency rating?” we all muttered. We chuckled at the billions of dollars spent to promote energy efficiency, yet this massive gap still exists with little or no concrete plans to solve the problem.
Regrettably, current industry practices encourage consumers to interpret equipment manufacturer’s laboratory efficiency ratings as the installed system efficiency they will be receiving. This assumption is far from true, yet it continues across the industry each day.
To summarize: Highly rated efficient equipment, installed safely and to code, does not assure an efficient installation.
A New Performance-Based Installation Definition
The discussion turned to the committee’s Field Testing Data Specification currently being completed by a working group under the leadership of Peter Jacobs. The outcome of this test procedure is an installed system efficiency scoring method that will quantify the level of efficiency earned by the installation process.
This test and calculation method:
• Shifts the focus onto the system efficiency and capacity actually delivered into the building, and away from equipment-rated (potential) efficiency and capacity.
• Compares installed system delivered capacity to bench-rated equipment capacity
• Can also be expressed as an installed system field EER with the addition of power measurements for regulators and utility companies
This field measured data is then used to score the percent of efficiency of the installed system compared to the rated capacity of the equipment.
The baseline for the score is the rated capacity of the equipment, or what the equipment should produce under ideal conditions. So, in other words, a perfect installation could score 100%.
An example would be a system rated at 56,000 Btu would deliver 56,000 Btu into the building. 56,000 Btu divided by 56,000 Btu equals 100%.
A more realistic example would be a 56,000 Btu system delivering 32,000 Btu into the building. This installation would be scored by dividing the 32,000 by 56,000 resulting in an installation efficiency score of 57%
Defining an Efficient Installation
The committee has not yet completed its work, and there are many more details to the story. Rest assured that a new definition is well underway. This new definition will provide for a scoring system for a level installed efficiency. This is the missing link to installation efficiency.
The new definition opens doors for the HVAC segment of the energy efficiency industry, but more important, it opens a new door for each of us, regardless of our role in the HVAC industry.
Is this definition perfect yet? No it is not. But the ability for us to move beyond equipment-rated efficiency and to grade, score, or rate the level of efficiency of the installation of an HVAC system is a new frontier. This frontier will grow, expand, and improve with time as we get more experience, advanced test methods, and enhanced test instruments and software.
What Kind of Systems Can Be Scored?
This test method can be used for scoring existing HVAC systems, recently retrofitted HVAC systems, or newly installed HVAC systems.
Existing Systems – Suppose you have an old 10 EER-rated packaged unit installed on a home or office building. The capacity of the equipment is rated at 44,000. Sure it’s old and tired, obviously the duct system probably matches it, but this test method can still be used to score the installation and operation of the system.
Calculate the heating or cooling Btu delivery of the system into the building by measuring airflow, temperatures, and pressures. Then divide the delivered Btu into the rated Btu to score the system.
Retrofitted Systems – Say you have replaced equipment and upgraded the duct system. By performing the same test before the retrofit and after the retrofit, you can show your customer the improvement you made in the installation of the system. Add to that higher efficiency equipment and there is an added bonus.
In addition, the testing verifies the equipment is installed better by comparing measured values to the manufacturer’s specifications. Sounds like lower warranty costs on are their way too.
Newly Installed Systems - Many believe code compliance assures an efficient installation, dream on. Code is a collection of measures as described in the first section of this article. Since there has been no measurement of installation efficiency, code is all we had to insinuate an efficient installation. Code alone is inadequate to deliver an efficient installation. Go measure it and you will discover new opportunity everywhere.
New systems are tested in the same manner as the old or retrofitted systems. Every existing new subdivision or building is filled with systems needing improvement.
By redefining an efficient installation, new liabilities and new opportunities are revealed.
What Percent Constitutes Efficient?
This emerging definition of an efficient installation is still under development. To date there are no official levels of efficient installation that have been established. We suspect there will be different levels for different types of installations.
The first step is to continue to establish a baseline for typical installations as they operate today. We have the 57% number, but more data from more sources are coming in daily.
First, we have to come to grips with how badly our systems are currently performing, then rewrite the book on where we’ll go in the future.
The good news is you can measure the level of performance of your customer’s systems and begin to improve the score of these systems right now.
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 test procedure to measure the delivered Btu of your systems, contact Doc at mailto:[email protected] call him at 800-633-7058. Go to NCI’s website at nationalcomfortinstitute.com for free information, articles and downloads.