Benchmarking provides high-level comparisons of whole-building energy use but cannot identify where energy is used or determine cost-effectiveness of upgrades. Retroactive energy modeling uses submetering and hourly data to calibrate an energy model that can answer these questions. By identifying lighting was used 5 extra hours daily, submetering showed controls could save more than lamp upgrades alone in just a few months. Preparing for measurement and verification involves obtaining operational data, connecting submeters to monitor real-time use, and educating occupants on energy impacts to identify hidden problems and most cost-effective upgrades.

1. GUIDING THE PA TH TO G RE E N
M e as u re m e nt & Ve rification
O r, h ow I le arne d to s top worrying and
love th e m e te r

2. S p e ake r Introd u ction
GUIDING THE PA TH TO G RE E N
Je re m y R . P oling, P E , LE E D AP + BD C
D ire ctor of E ngine e ring S e rvice s
Trans we s te rn S u s tainab ility S e rvice s

3. Le arning O b j ctive s
e
GUIDING THE PA TH TO G RE E N
• The d ifference between benchm arking and retroactive
m od eling
• C ases where m od eling can id entify problem s that
benchm arking will not
• The business case for m easurem ent and verification
• H ow to anticipate the process of calibrated m easurem ent and
verification and steps to a successful outcom e

4. Wh at is Be nch m arking?
GUIDING THE PA TH TO G RE E N
• Sim ple d efinition: com parison of one build ing against its
peers for the purpose of classifying a build ing as “efficient”
or “inefficient”
• Broad er d efinition: using whole-build ing characteristics and
aggregated whole-build ing energy use to d eterm ine the
Energy U sage Intensity (EU I) for a particular build ing. After
norm alizing that EU I for weather effects and com parison to
peers, id entify whether the build ing is a low-energy or high-
energy use build ing per square-foot of floor area.

5. Be nch m arking Tools
GUIDING THE PA TH TO G RE E N

6. Wh at can Be nch m arking d o?
GUIDING THE PA TH TO G RE E N
• Allow portfolio m anagers to d ecid e between upgrad ing one
build ing or another in their portfolio
• Provid e a basis for tenant lease transactions (careful!)
• C onfirm com pliance for incentive program s
• Earn certification und er program s like L EED and Green
Globes

7. Wh at C AN ’T Be nch m arking d o?
GUIDING THE PA TH TO G RE E N
• Id entify where energy is being used in a build ing
• D eterm ine the payback of Energy C onservation M easures
• Teach an operator how to run a build ing
• Teach occupants how to use less energy

8. Wh at is R e troactive M od e ling?
GUIDING THE PA TH TO G RE E N
• Typically com plies with ASH RAE Stand ard 1 4 or IPM VP
(International Perform ance M easurem ent and Verification
Protocol)
• U ses energy m od eling software to d escribe d etailed build ing
characteristics, such as:
– H ourly occupancy sched ules
– H ourly load profiles
– C hiller efficiency curves
– Econom izer operation
– System zoning

9. Wh at is R e troactive M od e ling?
GUIDING THE PA TH TO G RE E N
• C om pares pred icted energy
use against m easured energy
use using hourly energy d ata
and hourly weather d ata
• C alibrated to end -use
subm eters for energy use
verification
• Built to answer specific
questions about build ing
energy use

10. Title Bou t, R ou nd 1 :
GUIDING THE PA TH TO G RE E N
• At a m inim um , all build ings should be benchm arking energy
use m onthly as energy bills are received
– D evelops a habit of accounting for energy use
– D epend ing on location, m ight be legal requirem ent (N YC ,
San Francisco, Seattle… )
• Tools like Energy Star Portfolio M anager typically allow
benchm arking energy AN D water use
• M od eling will require at least an investm ent in intellectual
capital, in-house or on a consulting basis and typically a
capital investm ent in m etering

11. Title Bou t, R ou nd 1 :
GUIDING THE PA TH TO G RE E N
Benchm arking wins Round 1 , right?

12. Title Bou t, R ou nd 2: th e K O
GUIDING THE PA TH TO G RE E N
• After benchm arking, then what?
• Stud ies by large property m anagem ent firm s report 5% -1 0%
energy savings from real-tim e m etering of energy use
• M ost electric utilities charge for d em and , includ ing C om Ed
• M anufacturing com panies use d etailed energy m etering to
qualify the savings from Energy C onservation M easures,
particularly those that m ight im pact their processes

13. Title Bou t, R ou nd 2: th e K O
GUIDING THE PA TH TO G RE E N
Getting to significant energy savings
requires d etailed stud y of energy
end -use inform ation

14. Bu s ine s s C as e for M &V
GUIDING THE PA TH TO G RE E N
• Ind ivid ual subm eters for energy
end -uses can be relatively
afford able ($1 ,000 - $5,000
d epend ing on m anufacturer and
options selected )
• For argum ent’s sake, at $0.09
per kWh a 1 00,000 kWh annual
energy red uction will pay back
in 2 – 6 m onths
• So what d oes this actually look
like?

15. Bu s ine s s C as e for M &V
GUIDING THE PA TH TO G RE E N
• Exam ple: A 64,000 square foot build ing with typical 3-lam p,
32-watt T8 fluorescent lighting at the rule-of-thum b spacing
of 8 feet on-center has 1 ,000 lighting fixtures at a ballast
input of 86 watts. L ighting is controlled by tim e-clock.
O ccupants are in the build ing 8AM -5PM and housekeeping
is finished by 1 1 PM .
• For each hour of lighting use, the build ing electric m eter is
hit with 86 kWh. 1 00,000 kWh represents 1 ,1 63 annual
hours of lighting use, or approxim ately 4.65 hours a d ay for
250 business d ays per year.
• Sub-metering of lighting energy can identify the hours the
building lighting is running.

16. Bu s ine s s C as e for M &V
GUIDING THE PA TH TO G RE E N
• In the previous exam ple, the following Energy C onservation
M easures m ight be proposed :
1. Replacem ent of 32-watt lam ps with 25-watt lam ps for a
savings of 1 9 watts at the ballast input
2. U se of lighting controls to autom atically shut off lighting
d uring unoccupied hours
• Which d o you choose?

17. Bu s ine s s C as e for M &V
GUIDING THE PA TH TO G RE E N
• In absence of subm eters, you m ight choose EC M #1 . This
would require investm ent in slightly m ore expensive lam ps,
but could be accom plished with a payback of around 2-4
years.
• H owever, if you choose EC M #2, your payback could be 2-6
m onths. H ow is that possible?
• Subm etering the lighting energy id entifies that the build ing
operator set the tim e clock to keep lighting on for
housekeeping when they could use the local overrid e
switches instead , saving an average of 5 hours per d ay.

18. Bu s ine s s C as e for M &V
GUIDING THE PA TH TO G RE E N
• L ighting is the sim ple case
• M ore com plicated situations will
require m od eling at som e level:
1. C hiller replacem ents
2. Boiler replacem ents
3. Envelope retrofits
4. C ontrol replacem ents
• While there are estim ating
m ethod s and spread sheet
calculators, m od eling the
build ing will red uce com plexity
in calculations

19. P re p aring for M &V
GUIDING THE PA TH TO G RE E N
• N ew C onstruction
1. Request segregation of load s by end -use to m inim ize the
num ber of m eters required
2. U tilize an energy m od el and EU I targets early and often
in d esign for selecting system s so the d ata exists for
verification post-construction
3. C onnect real-tim e m eters to the build ing operator’s
com puter through a d ashboard (visibility =
accountability)
4. K eep it Sim ple

20. P re p aring for M &V
GUIDING THE PA TH TO G RE E N
• Existing Build ings
1. Id entify where you alread y have d ata (i.e. O ccupancy
hours through build ing security bad ge logging)
2. Id entify the big energy end -uses (chillers, lighting, plug
load s, etc.)
3. Sub-m eter 1 20V panels as these typically only see plug
load s or tenant load s
4. Ask about ad d itional BM S d ata points, such as energy
d ata from VFD s (m any can report voltage and am perage
if configured to d o so)

21. P re p aring for M &V
GUIDING THE PA TH TO G RE E N
• Existing Build ings
1. O btain real-tim e utility m eter read ings at a m inim um
and connect to the build ing operator’s com puter (repeat:
visibility = accountability)
2. C onnect new subm eters to the sam e d ashboard
3. Ed ucate build ing occupants on the im pact of their
energy use (think about the lighting exam ple – if an
occupant leaves a room of lights on for an extra hour,
the cost can be calculated read ily)

22. P re p aring for M &V
GUIDING THE PA TH TO G RE E N
• Existing Build ings
1. C onsid er sim ple, tem porary m etering investigations to
assist with m od eling (i.e. K ill-A-Watt for cubicle)
2. M & V d oesn’t have to capture everything – while you
m ight m iss som ething if it isn’t com prehensive,
subtractive m ethod s can also be effective
3. U se a “paid from savings” approach: in the exam ple
before, if the m etering pays back in 6 m onths whereas
the lighting retrofit would have taken 2-3 years to pay
back, use a portion of the “ad d itional” 1 8-30 m onths of
savings to pay for the investigation of ad d itional end -
uses

23. C onclu s ions
GUIDING THE PA TH TO G RE E N
• Benchm arking usually only gets at whole build ing d ata,
m easurem ent & verification strategies, includ ing calibrated
sim ulation, help answer the “what” and “why” questions
• End -use m etering can be very afford able and can id entify
hid d en energy problem s
• C alibrated sim ulation will account for ad d itive effects of
EC M s in a less com plex way than spread sheet calculations

24. GUIDING THE PA TH TO G RE E N
Q u e s tions ?
j re m y.p oling@ trans we s te rn.ne t
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