for air-tightness of the building envelope, moving ductwork into
conditioned space, having zero duct losses to the exterior, and
other benefits. All of this adds up to improved performance that
can be documented and proven for code compliance by using
energy performance analysis software.
And, the final compliance method, a new compliance method in
the 2015 IRC, is the Energy Rating Index.
As mentioned earlier, Energy Rating Index, or ERI, is a calculated
number, on a linear index scale, constructed with the ERI
reference design having a value of 100 and a residential building
that uses no net purchased energy having an index value of 0.
A one percent change in the total energy use of the rated design
relative to the total energy use of the ERI reference design shall
be represented by a change of 1 on the index scale. So, an ERI
of 55 means that the proposed design outperforms the ERI
reference design by 45 percent.
For the purpose of the Energy Rating Index, the code identifies
that the ERI reference design shall meet the minimum
requirements of the 2006 International Energy Conservation
Code prescriptive requirements.
To qualify for ERI compliance, the maximum energy rating index,
allowable by climate zone, is identified in table 1106.4:
CLIMATE ZONE ENERG Y
For example, in Climate Zone 3, like Dallas, TX, to qualify for ERI
compliance, the building would have an energy rating index of
51. This means that the building would use 49% less energy than
the 2006 IECC code minimum for the same building.
The building can have any design, it can have any building
envelope and it can have any insulation values, as long as the
analysis shows that the building will outperform the 2006 code
minimum for the same building by at least 49%.
Just like the performance method, ERI requires a report that
shows the proposed design meets the requirements of the
Energy Rating Index using calculations from an energy modeling
software tool. The most common analysis to meet ERI is a
HERS rating by a HERS rater, using REM/Rate analysis software.
However, any analysis software can be used including:
• Elite RHVAC
• Wrightsoft Right-J8
• Florida Solar Energy Center’s EnergyGauge
The ERI compliance method is new to the 2015 code and
offers another way to provide compliance when building
high performance systems.
So, from a building envelope standpoint you have three
options to make sure that you and your customers are
energy code compliant:
- the prescriptive requirements
- the performance method
- the energy rating index method
This is what the authority having jurisdiction, AHJ, is
looking for. And the verification that they are looking
for is the energy analysis report and the corresponding
energy code certificate, it is mandatory.
Overall, the energy code certificate is the responsibility
of the builder or the registered design professional and
should be posted on or in the electrical distribution
panel. And it should list the following:
• R-values of insulation installed in or on ceiling/roof,
walls, foundation (slab, basement wall, crawl space
wall and/or floor) and ducts outside conditioned
• U-factors for fenestration and the solar heat gain
coefficient (SHGC) of fenestration
• Results from any required duct system and building
envelope air leakage testing done on the building
• Types and efficiencies of heating, cooling and
service water heating equipment, if applicable
• Where there is more than one value for a
component, the certificate shall list the value
covering the largest area.
As an insulation professional, your activities are only a
portion of the overall energy code certificate, but you
should supply this information. To provide the best
service to your customers, in my opinion, it is your
responsibility to make sure that you leave behind an
insulation certificate on your jobs.
If, by chance, you are not actively using insulation
certificates, you can get a sample certificate from SPFA
technical documents, SPFA-148, or possibly even from
your material supplier.
On all of your projects in the future, make sure you are
involved in the energy code compliance conversation
and that you leave behind an insulation certificate, after
all you are the insulation expert.
Robert Naini has a Bachelor’s of Science in Mechanical
Engineering and an MBA from the University of Texas
in Arlington. With more than a decade of experience on
the cutting edge of spray foam insulation, he has helped
hundreds of owners and managers grow their business
with a unique knowledge base including spray foam sales
and marketing, employee and applicator training, building
science awareness and building code expertise. Spray Foam
Advisor offers web-based training and education, with videos,
articles, blogs and more, to help solve problems for spray foam
professionals and the construction industry.