ENERGY STAR®
PortfolioManager"
DataTrends
Energy Use in K-12 Schools
Up to 250 buildings
251-500 buildings
K-12 Schools
Using Portfolio Manager
51,500 Properties
5.4 Billion ft2
Average
ENERGY STAR Score
The U.S. Environmental Protection Agency's (EPA) ENERGY STAR Portfolio Manager is
changing the way organizations track and manage energy, Because of this widespread
market adoption, EPA has prepared the DataTrends series to examine benchmarking and
trends in energy and water consumption in Portfolio Manager. To learn more, visit
www.energystar.gov/DataT rends
Benchmarking by State
Number of K-12 School Buildings
What is a typical operating profile?
Energy use intensity (EUI) ranges from less than 50 to more than
500 kBtu/ft2 across all K-12 School buildings, with those at the
95th percentile using almost 4 times the energy of those at the
5th percentile. The distribution has a negative skew, which
means the most energy intensive buildings are much further
away from the median than the most efficient. Buildings may use
more or less energy for many reasons, including variable
equipment efficiency and energy management practices, as well
as variations in climate and building activities.
o
¦ 501-1,000 buildings
¦ 1,000 - 2,000 buildings
¦ More than 2,000 buildings
5,000
S, 4,000
O) '
= 3,000
m
4—
O
5 2,000
-Q
1,000
Portfolio Manager Median = 123 kBtu/ft2
J
L i
;
95th percentile = 224
5th percentile = 63
Source EUI (kBtu/ft2)
The median K-12 School building in Portfolio Manager is
approximately 75,000 square feet and has just over 2 computers
per thousand square feet. But the typical building use patterns
observed in Portfolio Manager vary just as much as energy. As
you can see, there are K-12 Schools of all shapes and sizes
benchmarking in Portfolio Manager.
Range of Values
Building
Characteristic
5th
percentile
Median
r
95th
percentile
Square Feet
22,912
74,671
282,507
/¦W4-H-V-'
Computers
51 per 1000 ft2
0.57
2.11
4.99
i
Walk-in Refrigeration
Units per 1000 ft2
0.00
0.01
0.04
-
Cooking?
-
80% say yes
-
Open Weekends?
-
24% say yes
-
High School?
~
18% say yes
-
Irtl
Heating
Degree Days
971
4,627
7,035
<%¦
Cooling
Degree Days
262
1,152
3,595
What is Source Energy? Source energy is the amount of raw fuel required to operate your building. In addition to what you use on-
site, source energy includes losses from generation, transmission, and distribution of energy. Source energy enables the most
complete and equitable energy assessment. Learn more at www.enerqvstar.qov/SourceEnerqy
-------
What characteristics affect
energy use?
How does EPA's ENERGY STAR score
vary with energy use?
Building activity and climate are often correlated with energy
consumption. For example, schools that experience more
cooling degree days (CDD), have more walk-in refrigerators (a
measure of cafeteria activity), or more computers per square foot
use more energy, on average. The orange trend line in the
graphs below is the steepest for CDD, meaning CDD has a
stronger effect on energy than refrigerators or computers. While
these trends hold true on average, two buildings with the same
CDD could have very different energy, as shown by the range in
the blue dots. Similar trends can be seen for other indicators of
building activity. For example, energy use is higher for high
schools than elementary schools.
c§p Cooling Degree Days
2000 3000
Cooling Degree Days
500
450
400
350
300
250
200
150
100
50
0
| Walk-in Refrigerators
* *^ > : • * ' .* . **
.V ... * •• • *
500 -
0.02 0.04 0.06 0.08
Walk-in Refrigeration/Freezer Units per 1000 ft2
Computers
0.1
450
SL 400
350
v 200
2 4 6
Personal Computers per 1000 ft2
EPA's ENERGY STAR score normalizes for the effects of
operation. While buildings with lower EUI generally earn higher
scores on the 1-100 scale, an individual building's result
depends on its activities. For any given EUI, a range of scores is
possible.
ENERGY STAR Score Range
"ii
For any value of EUI,
a range of ENERGY STAR
scores can be expected
100
0>
O)
k
cc
F
70 -
o
o
V)
QL
£
50 -
(')
30 -
Q£
LU
z
20 -
LU
10 -
ll.l.
Range represents
10th - 90th percentile
values for score
0 50 100 150 200 250 300 350 400 450 500+
Source EUI (kBtu/ft2)
Let's look at two K-12 School buildings, School A and School B.
They have the same EUI of 120 kBtu per square foot, and are
identical except that School B has more computers and walk-in
refrigeration units per square foot. Because School B has more
intensive activities, it is expected to have a higher EUI than
School A, based on ENERGY STAR scoring models. Since
School B is expected to use more energy, but actually uses the
same energy, it earns a higher score.
Computers: 50
Refrigerators: 1
Computers: 150
Refrigerators: 3
Expected EUI:
144
Expected EUI:
170
¦¦¦¦I
BI!I>
Kill
October 2012
Note: Number and floor area of buildings bench marked
includes cumulative data through 2011. Analysis of energy
use and building activity includes buildings bench marked
between 2006 and 2012. The data is self reported and has
been filtered to exclude outliers, incomplete records, and test
facilities. Portfolio Manager is not a randomly selected sample
and is not the basis of the EN ERG Y STAR score. To learn
more, visit: www. energ vs tar. gov/Da ta Trends.
United States
Environmental Protection
Agency
------- |