Berkeley's Building Energy Saving Ordinance (BESO) requires energy assessments of homes and buildings to identify efficiency opportunities. Assessments have found that insulation, air sealing, and high-efficiency water heaters are often recommended together. Analysis of energy usage data shows that homes in northern Berkeley hills use the most energy per household. Single family homes also use more energy than multi-family homes. Further promoting solar installations, especially in areas with high potential but low adoption like West Berkeley, could help reduce emissions. Smart metering technologies may provide more granular energy usage data to better inform policy.

1. Students Christopher Chutz | Greg Lyons | Lottie Macnair | Molly McCormick | Rei Van Instructors Ginette Wessel | Rick Kos | Alison Ecker | Aaron Welch | Eric Anderson | David Koo[IN]CITY Summer 2016, UC Berkeley
DECODING BUILDING
ENERGY USE IN BERKELEY
44%of all Berkeley’s greenhouse gas
emissions in 2012 were due to energy
used in residential or commercial
buildings
Building Energy Saving Ordinance2015
Residential Energy Conservation Ordinance required all homes
to complete up to 11 minimal energy efficiency measures when a
home was sold, transferred, or underwent major renovations.
Building Energy Saving Ordinance (BESO) requires Berkeley
building owners to complete energy efficiency opportunity
assessments.
These findings are made transparent to the public in order
to provide residents and building owners with means and
motivations to reduce their energy consumption, increase savings,
and promote sustainability and resiliency citywide.
Why do we need to reduce building energy use in Berkeley?
How did BESO originate?
BERKELEY CLIMATE ACTION PLAN
Buildings Transportation
& Land Use
Community
Outreach
Waste
Management
Adaptation &
Resilience
Commercial Energy Conservation Ordinance required all
commercial buildings to meet minimal energy efficiency measures
when a building was sold or transferred.
Neither state
ordinance
mandated any
public reporting,
or achieved deep
energy savings.
Spatial analysis was conducted which helped to identify patterns
and inform policy making. The following presentation covers:
• the background of BESO
• how it works and who it affects
• upgrades and rebate opportunities
• current energy analysis
• recommendations for further work
Berkeley residents voted to take decisive action on global warming by approving Measure
G, which advised the Mayor to work with the community to develop a plan for an 80%
reduction in Berkeley’s greenhouse gas emissions by 2050.
2009
2006
1993
1987
Purpose
RECO
CECO
MEASURE G
Reduce emissions 30% by 2020
80% by 2050
“Using energy information and a whole-building performance approach to
gain deeper energy savings”

2. Students Christopher Chutz | Greg Lyons | Lottie Macnair | Molly McCormick | Rei Van Instructors Ginette Wessel | Rick Kos | Alison Ecker | Aaron Welch | Eric Anderson | David Koo[IN]CITY Summer 2016, UC Berkeley
DECODING BUILDING
ENERGY USE IN BERKELEY
JO
Jo is a realtor working in
West Berkeley.
Jo assists in time
of sale compliance,
helping sellers
complete assessments
and helping buyers
understand them.
Jo’s clients make
upgrades according to
the recommendations
that were made.
Jo encourages her
clients to prioritize
efficiency when selling
a house by indicating
the increased value of
green homes.
Charlie is buying a
Victorian home on the
Northside.
Charlie arranges for
an assessment of his
home, and he reviews
the report.
Charlie receives a
rebate, which allows
him to invest in
efficiency upgrades
and reduce his energy
bills.
Charlie sees the value
of his investment in an
improved score and
reduced utility bills.
CHARLIE
Every home (all
buildings starting in
2018) undergoes a
comprehensive
energy
assessment
by a registered
assessor that will
determine the home
energy score.
The assessors
provide tailored
recommendations
on how to save
energy as well
as incentives
for energy
efficiency
upgrades, and
rebates to the
owner.
Assessments
are then made
publicly
available
and are provided to
prospective buyers
for all properties,
both residential
(prior to sale) and
commercial (on a
phase-in schedule).
STAGE 1 STAGE 2 STAGE 3
SAM
Sam works as an assessor
evaluating home energy
scores.
Sam reviews and
assesses various
residential and
commercial properties.
Sam provides home
energy scores
and matches her
recommendations to
available rebates.
This information
is shared with the
city government,
provides a better
understanding of the
city’s energy usage and
targets policies more
effectively.
People
Whom does BESO affect?
How does BESO work?

3. Students Christopher Chutz | Greg Lyons | Lottie Macnair | Molly McCormick | Rei Van Instructors Ginette Wessel | Rick Kos | Alison Ecker | Aaron Welch | Eric Anderson | David Koo[IN]CITY Summer 2016, UC Berkeley
DECODING BUILDING
ENERGY USE IN BERKELEY
Loans for:
Federal
Property Assessed Clean Energy (PACE)
• washing machine
• water heater
• insulation
California
The Home Energy Score (HES) is a national
rating system developed by the U.S.
Department of Energy, which models expected
energy use. Recommendations show how to
improve the energy efficiency of a home to
achieve a higher score and save money.
Sam conducts an energy assessment of Charlie’s
home.1
Sam records details about Charlie’s house, including:
2
3 Charlie’s home receives a home energy score of 3, indicating
that it could benefit from significant energy improvements.
HES is based on 40 data points taking into
account factors such as airtightness, wall
construction, windows, heating and cooling
systems, and estimated yearly energy usage.
insulation
type
window
area
heating
method
Sam recommends a number of improvements, and provides
Charlie with a roadmap of relevant rebates and financing
options to help him:
1 2 3 4 5 6 7 8 9 10
What is the
Home Energy Score
(HES)?
A score of 10 indicates a house with
low energy usage.
A score of 1 indicates a house with
energy efficiency opportunities.
Charlie receives a PACE loan to help him finance
upgrades, as well as a rebate on a new water heater.
4
5
Program
building
envelope
Energy Upgrade California
Fannie Mae Home Efficiency Loan
Tax incentives
Rebate
Programs
Financing
Options
Mortgage loans providing affordable
financing for efficiency improvements
Includes rebates for:
• solar panels
• geothermal heat pumps
• small wind turbines
Includes rebates for:
• energy efficiency upgrades
• renewable energy installations
What is the BESO process?

4. Students Christopher Chutz | Greg Lyons | Lottie Macnair | Molly McCormick | Rei Van Instructors Ginette Wessel | Rick Kos | Alison Ecker | Aaron Welch | Eric Anderson | David Koo[IN]CITY Summer 2016, UC Berkeley
DECODING BUILDING
ENERGY USE IN BERKELEY
over 300 homes assessed
PACKAGE 1
Insulation was one of
the most commonly
recommended items,
with floor insulation
recommended in
approximately 40% of all
homes.
Insulation was often
recommended for all areas
simultaneously.
On-demand water heaters
were frequently paired with
whole house air sealing and
gas furnaces.
Which upgrades are often recommended together?
ANALYSIS 1:
Home energy scores
Attic
Insulation
Wall
Insulation
Floor
Insulation
Whole House
Air Sealing
Duct
Repair
Central Gas
Furnace
Gas Storage
Water Heater
Gas On-Demand
Water Heater
Natural Gas
Wall Heater
Fireplace
Door Damper
Attic
Insulation
45% 89% 69% 47% 64% 47% 17% 9% 27%
Wall
Insulation
77% 84% 98% 45% 70% 39% 27% 18% 18%
Floor
Insulation
65% 36% 55% 40% 59% 57% 13% 9% 25%
Whole House
Air Sealing
76% 63% 84% 49% 71% 44% 19% 10% 22%
Duct
Repair
76% 43% 89% 72% 70% 46% 22% 13% 37%
Central Gas
Furnace
68% 44% 86% 68% 45% 54% 15% 11% 23%
Gas Storage
Water Heater
54% 26% 91% 46% 32% 58% 3% 11% 23%
Gas On-Demand
Water Heater
100% 92% 100% 100% 77% 85% 15% 23% 38%
Natural Gas
Wall Heater
70% 80% 90% 70% 60% 80% 70% 30% 20%
Fireplace
Door Damper
71% 29% 93% 54% 61% 57% 54% 18% 7%
average score of 4.71in Berkeley
average energy savings of 21%
How could we package upgrades to make them more affordable?
PACKAGE 2 PACKAGE 3
central gas furnace + floor insulation
ON
DEMAND
gas on-demand water heater + air sealing natural gas wall heater + whole house insulation
HOME ENERGY SCORES
ON
DEMAND
IF this is installed THEN this is installed __% of the time
101
What have Berkeley’s scores told us thus far?

5. Students Christopher Chutz | Greg Lyons | Lottie Macnair | Molly McCormick | Rei Van Instructors Ginette Wessel | Rick Kos | Alison Ecker | Aaron Welch | Eric Anderson | David Koo[IN]CITY Summer 2016, UC Berkeley
DECODING BUILDING
ENERGY USE IN BERKELEY
Based on 2015-2016 data, the overall energy usage map
on the left depicts the total residential and commercial
energy usage within Berkeley. The areas around
Downtown and West Berkeley have much higher energy
usage intensities, likely due to commercial land use.
The land use map on the right indicates that the
areas of high energy usage coincide with the areas
containing commercial buildings.
Energy
Intensity
Use
+ ÷)( =Total Annual Energy Usage
(Electric + Gas)
Area
Buildings varying in size and purpose consume energy differently, which can make comparing them difficult. Here we use
a metric called EUI which measures energy usage per square foot to compare the efficiency of residential and commercial
buildings across Berkeley.
kBtu per year square feet kBtu per square foot per year
This map shows that
commercial EUIs
vary widely between
zipcodes.
What kind of energy are we using in our city?
ELECTRICITY NATURAL GAS
The electricity usage
map on the left and
natural gas usage map
on the right indicate
higher usage overall
in Downtown Berkeley
with higher natural gas
usage in the Berkeley
hills.
In contrast to
commercial buildings,
this map shows that
residential EUIs are
largely consistent
between zipcodes.
ANALYSIS 2:
Energy snapshot
TOTAL ENERGY USAGE LAND USE
How else can we compare building energy usage?
HighLow
HighLow HighLow
CommercialResidential
COMMERCIAL EUI RESIDENTIAL EUI
High
Low
Where is the most energy used in Berkeley?

6. Students Christopher Chutz | Greg Lyons | Lottie Macnair | Molly McCormick | Rei Van Instructors Ginette Wessel | Rick Kos | Alison Ecker | Aaron Welch | Eric Anderson | David Koo[IN]CITY Summer 2016, UC Berkeley
DECODING BUILDING
ENERGY USE IN BERKELEY
• Downtown Berkeley uses the most residential
energy in the city
HOME VINTAGE
ENERGY USAGE
PER HOUSEHOLD 2015-16
% OF SINGLE FAMILY
HOUSING
MEDIAN YEARLY INCOME
TOTAL RESIDENTIAL
ENERGY USAGE 2015-16
ANALYSIS 3:
Residential energy
• Homes in the northern hills consume the most
energy per household
• Housing stock is relatively uniform
in age
• Oldest homes are concentrated in
the western section of the Berkeley
hills and the central portion of the
city
• Berkeley’s highest income
households are located in the hills
• Homes in this area use relatively
more energy, especially from
natural gas.
• Single family housing is
concentrated in the northern hills
• Multi family housing is
concentrated around the UC campus
• Single family households use more
energy than multi-family.
What factors affect residential energy use?
HighLow HighLow
HighLow HighLow HighLow
Who is using this energy?

7. Students Christopher Chutz | Greg Lyons | Lottie Macnair | Molly McCormick | Rei Van Instructors Ginette Wessel | Rick Kos | Alison Ecker | Aaron Welch | Eric Anderson | David Koo[IN]CITY Summer 2016, UC Berkeley
DECODING BUILDING
ENERGY USE IN BERKELEY
Berkeley could save up to 300,000metric tons of CO2
emissions every year if the
city fully utilized its solar potential - that’s almost
as much as San Francisco’s now-derelict Hunters
Point plant emitted every year.
The map of
installed solar
projects shows
a concentration
of installations in
North Berkeley
and the hills, while
the greatest solar
potential lies
largely in West
Berkeley.
West Berkeley
was also an area
with relatively
high usage, and
therefore could
benefit from solar
installations.
1. It’s clean 2. It’s not as expensive as you think
Solar is becoming cheaper: a
typical solar installation can cost
as little as $15,000 and could pay
for itself after just 2 years with
associated US tax credit programs.
Energy produced using
solar panels generates
20x less CO2
than
energy from coal
burning.
Is Berkeley utilizing its solar potential?
ANALYSIS 4:
Solar potential
CURRENTLY INSTALLED SOLAR vs.
ENERGY USAGE
CURRENTLY INSTALLED SOLAR vs.
SOLAR POTENTIAL
High usageLow usageHigh potentialLow potential Solar installation
1400
1200
1000
800
600
400
200
Totalinstalledcapacity
90
Priceofsolar($/Watt)
80
70
60
50
40
30
20
10
00
1975 1980 1985 1990 1995 2000 2005 2010 2015
Number of solar installations vs. Price of solar energy
Why choose solar?

8. Students Christopher Chutz | Greg Lyons | Lottie Macnair | Molly McCormick | Rei Van Instructors Ginette Wessel | Rick Kos | Alison Ecker | Aaron Welch | Eric Anderson | David Koo[IN]CITY Summer 2016, UC Berkeley
DECODING BUILDING
ENERGY USE IN BERKELEY
What are the next steps in the analysis?
Single family housing uses
more energy.
Home vintage does not appear
to correlate with energy usage.
Go after the “low-hanging fruit”:
package fast and affordable
upgrades for single family
homeowners.
Higher income areas use
more natural gas, and have
a larger number of solar
installations.
Carry out more detailed analysis
of how vintage affects energy
use as more data is obtained.
Findings and
Recommendations
There is potential for more
solar to be installed in West
Berkeley.
Promote active solar heating
technologies in high income
areas.
Assess solar potential in
industrial and commercial areas
during the next phase of BESO.
FINDINGS RECOMMENDATIONS CHALLENGES
Effectively co-operate with
rebate providers.
Ensure that HES data is of high
quality, to be able to identify
relationships between housing
characteristics and energy usage.
Regulatory and economic
barriers to matching solar
potential with demand.
What smart technologies could Berkeley utilize?
• Smarter utility meters could transmit data in real time at a more granular level
• This data could allow Berkeley to better understand its energy usage over
time and target policy more effectively.
• Smart home metering could also give Berkeley residents a better
understanding of their own energy usage in order to inform their energy use
decisions.
• Multi-unit residential buildings could be outfitted with meters that allow
the owner to better understand energy usage of individual units within their
buildings.
Smart GridsSmart Metering
• Smart Grids use technology to detect and react
to local changes in energy usage.
• By creating a smart grid of 30-50 clustered
homes, Berkeley could...
»» Track energy usage at the circuit level, rather
than by home, to receive more coherent data
»» Tailor utility programs to demand response
More granular data
for more focused
targeting
Greater transparency
between Berkeley
and PG&E
More detailed
analysis of how and
where energy is used
Structured
recommendations for
achieving energy goals
What have we found, and what should be done?