ASHRAE Journal - November 2020 - 10

LETTERS

Performance
Contract Spurs
Energy Efficiency
The August 2020 Technology Award
article, "Performance Contract Spurs
Energy Efficiency," by Matthew
Longsine, P.E.; Tom Marseille, P.E.;
Charles Chaloeicheep, P.E.; and
Zach Stevens raises some concerns.
I applaud the efforts of the design
team in achieving success with
energy efficiency. While the title is
about a "performance contract,"
there is no description of what the
contract contains or requires. What
were the consequences of either
exceeding or not meeting the EUI
target? Were any not met until now?
Were there any disputes or adjustments made? What "adjustments"
are provided in the contract?
Since the building was occupied in
2017, why wasn't any later metered
energy data shown? Certainly, the
authors have the data as it is the
basis for their contract. Month-bymonth and year-by-year tabular
data would be more informative. To
what extent were the performance
goals reached or not and why?
CBECS does not publish EUI data
for office buildings by city. There
are EUIs for many other criteria for
all office buildings, such as geographical region, building size, year
built, etc. If the authors derived the
EUI for Seattle from the average
of all existing office buildings, the
basis or their reference should be
provided.
Table E2 of the 2012 CBECS shows
the EUI of all existing office buildings in the U.S. is 77.8 kBtu/ft2.
Since Seattle is in a more moderate
climate than much of the U.S., the
EUI for existing office buildings
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should be lower, and not the EUI of
90 kBtu/ft2 claimed in the article.
The authors claim 44.6% savings
compared with ASHRAE Standard
90.1-2007 with a 30.1 kBtu/ft EUI
for this building. That would imply
a new Standard 90.1-2007 compliant office building in Seattle would
have an EUI of about 54.4 kBtu/ft2.
Yet, in the published 2018 City
of Seattle benchmarking report
for 69 million ft2 of existing offices
of all ages, the average EUI is
59 kBtu/ft2, not the 90 kBtu/ft2
claimed from CBECS, and only
slightly higher than a new Standard
90.1-2007 compliant office building.
Does this mean that compliance
with Standard 90.1-2007 for all new
office buildings in Seattle would not
show much improvement over the
actual performance of all existing
office buildings?
The article claims water "savings,"
but does not show any water consumption, so readers can compare
with their own experience. Is water
use part of the performance guarantee? The authors estimate that
existing four-person Seattle homes
each use 127,000 gallons per year
seems high, and no basis or reference is provided for that value. The
King County (Seattle) website shows
that in 2009 the average residential water consumption was about
36 gallons per person per day, so for
a family of four, the average annual
home water consumption would be
about 53,000 gallons per year, or
typical of many cities.
There ought to be more rigor and
perspective given in the numbers
to convince those familiar with
similar buildings that this LEED
Platinum building is unique. When
the contract is complete, will the

N OVEM BER 2020

operators be able to maintain the
complex controls and equipment
necessary to continue the alleged
savings? No consideration was given
to the Seattle Energy Code or the
Washington State Energy Code, both
of which have requirements well
above Standard 90.1-2007.

Larry Spielvogel, Fellow/Life Member ASHRAE,
Bala Cynwyd, Pa.

The Authors Respond
Thanks, Larry, for reading about
our project and the thoughtful
response. We should be able to
address your questions fairly easily.
Performance Guarantee
Contract. The performance guarantee contract included a five-year
performance period and withheld $420,000 from the design
team until the guarantee was
met. Adjustments were allowed
for tenant-driven energy end use
increases, specifically IT/server
loads above an agreed-upon level,
and increased hours of operation.
When tenant behavior in these
categories exceeds the energy consumption levels outlined in the
performance agreement, they are
excluded from the building energy
consumption being compared to
the EUI target. No adjustments were
made during Year 1. A very small
adjustment was made during Year 2
based on server loads exceeding the
allotted amount by about 2%.
More Recent Energy Data. The
building was officially occupied
per the performance agreement in
November of 2017. The data provided was for the first full year of
occupancy. Year 2 analysis has been
completed in which the building
continued to operate below the
performance target, with an EUI
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ASHRAE Journal - November 2020

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