The document provides an overview of net zero energy buildings (NZEB) in the US. It discusses various building energy ratings systems like LEED and Green Globes. It then examines examples of early NZEB projects in Florida and Massachusetts that incorporated high insulation, efficient appliances and HVAC systems, and solar photovoltaics to achieve net zero status. The document concludes with descriptions of two high performance NZEB case studies, one in New Jersey utilizing solar thermal and PV, and another in Vermont using a ground source heat pump and wind power.

1. Overview of Net Zero Energy Buildings
in the US
Jiazhen Ling, Reinhard Radermacher

2. Contents
• Building Energy Ratings
• Net Zero Energy Buildings and Examples
• Technologies for NZEB
• Cost Analysis
• Incentives to NZEB
• Others

3. Building Energy Ratings
• Leadership in Energy and Environmental Design
(LEED)
• Certified (40-49 points); Silver (50 – 59 points); Gold
(60-79 points); Platinum (80 – 110 points)
• Green Globes
• One Globe (350-540 points); Two Globes (550-690
points); Three Globes (700-840 points); Four Globes
(850-1000 points)
• Home Energy Rating System (HERS)
• Scale from 0 to 100; 0 indicates the building uses no
net purchased energy; the lower the value, the better
• Net Zero Energy Buildings

4. LEED Scoreboard
Possible Points
(for homes)
Possible Points
(for Multi-family)
Integrative Process 2 2
Location and
Transportation 15 17
Sustainable Sites 8 9
Water Efficiency 13 13
Energy and Atmosphere 34 30
Material and Resources 11 9
Indoor Environmental
Quality 15 18
Performance 2 2
Innovation 6 6
Regional Priority 4 4
Total 110 110
Source: http://www.usgbc.org

5. Green Globes® Overview
• A web-based program for green building guidance
and certification
• The program supports new construction, existing
buildings and healthcare buildings
Environmental
Assessment Area
New Construction
points
Environmental Assessment
Area
Existing
Buildings Points
Energy 380 Energy 350
Water 85 Water 80
Resources 100 Resources 110
Emissions 70 Emissions 175
Indoor Environment 200 Indoor Environment 185
Project Management 50 Environmental Management 100
Site 115
Total Points 1000 1000
Source: http://www.thegbi.org/green-globes/new-construction.shtml

6. Green Globes Versus LEED
Criteria Green Globes LEED
Program Points 1000 110
Program Delivery Web enabled interactive questionnaire Online forms
Incorporate Life
Cycle Assessment
YES NO
Certification Process Assessor assigned/on-site building audit with
team
Fill out
assessment form,
submit, await
results
Certification Ratings 4 Globes
3 Globes
2 Globes
1 Globe
LEED Platinum
LEED Gold
LEED Silver
Certified LEED
Time Required to
Complete
Documentation
Cost to Certify a
Typical Bldg. >
100,000 sq. ft.
$ $$$
Source: http://www.thegbi.org/green-globes/green-globes-leed-green-building-certification.shtml

7. A Few Numbers
• LEED Certified (as of: 10/2/2012)[1]
• LEED Platinum: 945 ; LEED Gold: 6215; LEED
Silver: 5042; LEED Certified; 3023
• Green Globes:(as of: 10/2/2012)[2]
• New Constructions:
• 4 Globes: 4; 3 Globes: 29; 2 Globes: 52; 1 Globes: 30
• Existing Constructions:
• 4 Globes: 10; 3 Globes: 228; 2 Globes: 87; 1 Globes: 10
[1]: Public LEED Project Directory (http://www.usgbc.org/LEED/Project/CertifiedProjectList.aspx)
[2]: Green Globes Overview (http://www.thegbi.org/green-globes/)

8. LEED Gold Buildings at UMCP
8

9. Net-Zero Energy Building Definitions
• In general, a net-zero energy building
produces as much energy as it uses over the
course of a year
• Net-zero energy buildings are very energy
efficient
• The remaining low energy needs are typically
met with on-site renewable energy

10. Types of NZEB
• Net Zero Site Energy
• Net Zero Source Energy
• Net Zero Energy Costs
• Net Zero Energy Emissions

11. Current Status of NZE Buildings in US
• ZEB (or better low energy buildings)
research is currently being supported by US
DOE Building America Program
• Other industry-based consortia and national
laboratories such as NREL, LBNL, NIST and
ORNL are also actively involved
• President Obama set up the goal that 100%
of all new federal buildings achieve Zero-Net-
Energy by 2030

12. US Roadmap towards nZEB
• Executive Order 13514
• All new Federal buildings that are entering the
planning process in 2020 or thereafter be
“designed to achieve zero-net-energy by 2030
• DOE defined two milestones
• Marketable Net Zero Energy Homes by the year
2020
• Commercial Net Zero Energy Buildings at low
incremental cost by the year 2025
• 100% reduction in fossil-fuel energy use
(relative to 2003 levels) for new Federal
buildings and major renovations by 2030

13. Worldwide Zero Energy Targets
COUNTRIES (REGIONS) ZERO ENERGY TARGET
USA (California) Net zero energy performance in residential
buildings by 2020 and in commercial buildings by
2030
USA (Massachusetts) Net zero energy for all new buildings by 2030
South Korea All residential buildings are required to achieve
zero energy emissions by 2025
England Zero carbon (emissions) homes by 2016
Wales Zero carbon (emissions) buildings ( in relation to
space heating, hot water and lighting) by 2011
France By 2020 all new buildings are energy-positive
The Netherlands Energy-neutral buildings in 2020
Hungary Zero emissions for all new buildings by 2020
Source: Maria Kapsalaki & Vitor Leal (2011): Recent progress on net zero energy buildings, Advances in Building
Energy Research, 5:1, 129-162

14. Approach for Achieving NZEB
Source: National Science and Technology Council, Federal Research and Development Agenda for Net-zero
Energy, High-Performance Green Builings,2008

15. Analyzing the Least-Cost Path
Reduced cost
by increasing
building
efficiency
Additional options until cost of saving
energy equals cost of onsite power prod.
No changes in
design, savings
result from additional
onsite power
capacity
PV systems used for
on-site power
generation

16. Earlier NZE Houses – PVRES, Florida
Lakeland Zero Energy Home (solid
circle);
control home (dotted circle), built
Lakeland , FL in 1998
• Single family home (one story, 3BR,
2425 sq. ft.)
• Two houses, one PVRES and one
control home, have the same floor
plan
• PVRES has a 4 kW PV system (2.7
kW facing south, 1.3 kW facing
west)
PVRES Home Features Control Home Features
White reflective roof with R-30
ceiling insulation
Gray/brown asphalt shingle
roof, R-30 ceiling insulation
Exterior insulation over
concrete block system (R-10)
R-4 wall insulation on interiror
of concrete block walls
Advanced solar control double-
glazed windows
Single glazed windows with
aluminum frames
Down-sized SEER 14.4
variable speed AC
4-ton Trane heat pump (SEER
= 10; HSFP = 7)
Field-verified cooling coil air
flow
Low friction loss and sealed
duct system within the
conditioned space
R-6 ducts located in attic
Programmable thermostat
High efficiency refrigerator Standard appliances (electric
range, refrigerator and electric
dryer)
High efficiency compact
Fluorescent lighting
Standard incandescent lighting
(30 recessed can lights)
Source: Parker D., Very low energy homes in the United
States: Perspectives on performance from measured data,
Energy and Buildings, Volume 41, Issue 5, May 2009, Pages
512-520,

17. PVRES, Florida (Cont.)
Thermal and visible images of west-facing windows and shadows in the afternoon
Baseline home PVRES home
Source: Parker et al., Field Evaluation of Efficient Building Technology with Photovoltaic Power Production in New Florida Residential Housing, Florida Solar
Energy Center, FSEC-CR-1044-98

18. PVRES, Florida (Cont.)
Thermal and visible images of west-facing windows and shadows in the afternoon
Source: Parker et al., Field Evaluation of Efficient Building Technology with Photovoltaic Power Production in New Florida Residential Housing,
Florida Solar Energy Center, FSEC-CR-1044-98

19. PVRES, Florida (Cont.)
Thermal images of air being drawn from the attic to the AHU in the
baseline house (center). The interior duct system in the PVRES shows
no problem
Source: Parker et al., Field Evaluation of Efficient Building Technology with Photovoltaic Power Production in New Florida Residential
Housing, Florida Solar Energy Center, FSEC-CR-1044-98

20. PVRES, Florida (Cont.)
Case
Descripti
on
AHU
status
Air
Changes
Per Hour
Interior
Temp (°F)
Exterior
Temp (°F)
Wind
Speed
(m/s)
Baseline Off 0.131 76 90.6 5.2
Baseline On 0.349 76 89.9 8.0
PVRES Off 0.085 74 86.5 9.5
PVRES on 0.131 74 85.6 10.2
Source: Parker et al., Field Evaluation of Efficient Building Technology with Photovoltaic Power Production in New Florida Residential Housing,
Florida Solar Energy Center, FSEC-CR-1044-98

21. PVRES, Florida (Cont.)
• From April-August, averaged 15.66 kWh
delivered to the utility grid every day
• The PVRES consumed averaged 22.0
kWh/day
• The PV system produced 71% of the daily
electricity required for the building operation
• During daytime hours the net impact on the
grid is nearly zero
• During evening hours all power required
came from the utility

22. PVRES, Florida (Cont.)
April 15 16 17 18 19 20
House thermal performance when unconditioned ( top baseline; bottom PVRES)

23. PVRES, Florida (Cont.)
Component Description Cost ($) Savings
kWh ($)
Simple payback
(Years)
Advanced windows $4,266 1,610 ($129) 33
White tile roof $10,829 1,342 ($107) 101
R-10 walls $11,500 307($25) 460
Wider overhang $1,882 537 ($43) 44
Interior duct system $950 1,150 ($80) 12
High efficiency AC $1,263 2,376 ($190) 7
Efficient Lighting $525 1,479 ($118) 4
High Efficiency refrigerator $298 388 ($31) 10
Solar water heater $2,989 2,097 ($123) 24
Utility integrated PV
system
40,000 5,600 ($448) 89
Preliminary economics of efficiency measures
Source: Parker et al., Field Evaluation of Efficient Building Technology with Photovoltaic Power Production in New Florida
Residential Housing, Florida Solar Energy Center, FSEC-CR-1044-98

24. NZE House in Stow, MA
Source: Engelmann, P., Roth, K., 2011, IEQ/IAQ and Energy Performance of Very Low-Energy Homes, Summer 2011 Residential
Ener. Eff. Tech. Update Meeting, Aug. 2011. web source:
http://apps1.eere.energy.gov/buildings/publications/pdfs/building_america/ns/eemtg082011_c4_very_lowe_homes.pdf

25. Energy production and consumption
End-energy usage breakdown
Source: Engelmann, P., Roth, K., 2011, IEQ/IAQ and Energy Performance of Very Low-Energy Homes, Summer 2011 Residential
Ener. Eff. Tech. Update Meeting, Aug. 2011. web source:
http://apps1.eere.energy.gov/buildings/publications/pdfs/building_america/ns/eemtg082011_c4_very_lowe_homes.pdf
NZE House in Stow, MA (cont.)

26. NZE House in Lebanon, NJ
Elements
Bldg. Orientation True south, Passive
solar heating, daylighting
Layout Open plan
Conditioned Area 4200 sf (390 sm)
Framing 2 by 4 at 16” O.C.
Type Single-family detached
Materials Douglas fir; Southern
Pine
Specifications
Slab Floors R-35 (6 m2K/W)
Foundation Walls R-35 (6 m2K/W)
Basement Ceiling None
Above Grade Walls R-35 (6 m2K/W)
Roof R-35 (6 m2K/W)
Window R-10 (2 m2K/W)
Relative Humidity 40-50%
Infiltration Rate 5.0 ACH@50Pa
4 bedrooms, 2.5 baths, living room,
dining room, kitchen, laundry room and
a basement
Source: Hoque, S., 2010, Net zero energy homes: an evaluation of two homes in the northwestern United States, Journal of Green Building, Vol. 5 (2), pp. 79-90.

27. Energy Systems
Energy Consumption
Heating Air(AHU) + Radiant
(Solar Thermal)
AC None
Water Heating Solar Thermal
Ventilation Nature
Energy Generation
Passive Solar
Heating
Yes
PV 9.8 kW
Wind None
Solar Thermal Yes
Source: Hoque, S., 2010, Net zero energy homes: an evaluation of two homes in the northwestern United States,
Journal of Green Building, Vol. 5 (2), pp. 79-90.
NZE House in Lebanon, NJ (cont.)

28. NZE House in Charlotte, VT
Source: Hoque, S., 2010, Net zero energy homes: an evaluation of two homes in the northwestern United States,
Journal of Green Building, Vol. 5 (2), pp. 79-90.
Elements
Bldg. Orientation True south, daylighting
Layout Open plan
Conditioned Area 2800 sq. ft. (260 m2)
Framing 2 by 6 at 24” O.C.
Type Single-family detached
Materials FSC Certified wood
Local crafted concrete
countertops
Local sustainable harvested
maple
Flooring & hardwoods
Cellulose & denim insulation
Reclaimed fir columns
LEED certification LEED Platinum
Specifications
Slab Floors None
Foundation Walls R-19 (3 m2K/W)
Basement Ceiling R-19 (3 m2K/W)
Above Grade Walls R-40 (7 m2K/W)
Roof R-56 (10 m2K/W)
Windows R-10 (2 m2K/W)
Relative Humidity 40-50%
Infiltration Rate 2.0 ACH@50Pa

29. Energy Systems
Energy Consumption
Heating Radiant (Ground source
HP)
AC None
Water Heating Instantaneous (on-
demand)
Ventilation HRV
Energy Generation
Passive Solar
Heating
No
PV None
Wind 10 kW
Solar Thermal Hybrid (GHP + on-
demand)
Source: Hoque, S., 2010, Net zero energy homes: an evaluation of two homes in the northwestern United States, Journal of
Green Building, Vol. 5 (2), pp. 79-90.
NZE House in Charlotte, VT (cont.)

30. EcoTerra HouseTM, Canada
http://sbrn.solarbuildings.ca/main.php?l=e&d=1&i=3&t=demoproje
cts
• Built in November, 2007
• Two-story detached home, 234
m2
• 3 kW BIPV/Thermal system on a
55 m2 south-facing roof (22
amorphous silicon 135W cells)
• 10 kW solar thermal generation
• Two-stage Geothermal heat
pump
Source: Noguchi et al., 2008, Net zero energy homes of the future: a case study of the EcoTerraTM House in Canada, Presented at the
Renewable Energy Congress, Glasgow, Scotland, July 19-25, 2008

31. EcoTerra HouseTM, Canada
Source: Noguchi et al., 2008, Net zero energy homes of the future: a case study of the EcoTerraTM House in Canada,
Presented at the Renewable Energy Congress, Glasgow, Scotland, July 19-25, 2008

32. Non-Residential Examples: Lewis Center, Ohio
Source:
http://www.oberlin.edu/archive/resources/phot
oguide/lewis_center.html
• Two-story, 13,600 sq. ft.
• Renovation completed in
2000
• Building includes
classrooms, offices, an
auditorium, an atrium
• 60-kW PV system covers
the entire roof (690 85-Watt
single crystalline modules)
Zone-decentralized heating and cooling system
For classrooms,
offices and corridors For auditorium
Source: Pless and Torcellini, 2004, Energy Performance
Evaluation of an Educational Facility: The Adam Joseph
Lewis Center for Environmental Studies, Oberlin College,
Oberlin, Ohio, NREL Technical Report, NREL/TP-550-33180

33. Lewis Center, Ohio (Cont.)
Source: Pless and Torcellini, 2004, Energy Performance Evaluation of an Educational Facility: The Adam Joseph Lewis Center
for Environmental Studies, Oberlin College, Oberlin, Ohio, NREL Technical Report, NREL/TP-550-33180
Building electric system plan and DAQ meter
locations
Average daily performance, March 1, 2001 through Feb. 28,
2002

34. The Science House, Minnesota
Source:
http://leedresource.wordpress.com/2012/02/11/ze
ro-energy-buildings-myth-or-must
• New construction
completed in 2003
• Single-story, 1530 sq. ft.
• Occupied by 2 people; 795
visitors per week
• Wood-frame structure
• 8.8 kW PV system
• Project cost: $650,000
1) Science house changes from energy user to energy
producer 2) new equipment plugged into the Science
House 3) Science House goes into unoccupied mode,
equipment except for card reader is turned off 4)
Science House becomes net energy user
Weekly Energy Balance in 2005

35. ORNL Office Building 3156
• Two-story, 6,940 sq. ft.
• Last renovation completed
in 2009
• 31 occupants; 23 offices +
1 conference room
• Commercial office, campus
• 51-kW PV system
• High efficiency packaged
terminal heat pumps
• Total project cost (land
excluded): $660,000
Renovation Highlights:
• R-23 roof insulation with a high-
performance reflective
membrane added
• High efficacy T8 lighting using
electronic ballasts
• Occupancy sensors to control
both HVAC and lighting
• A energy consumption
monitoring system to better
understand energy use profile
of the building
http://femp.buildinggreen.com/energy.cfm?ProjectID=1585

36. NIST nZEH Test Facility
• Located at Gaithersburg, MD
• Designed to achieve LEED platinum
• To demonstrate a residence, typical in DC area, can achieve nZEH
• To provide “real world” field data for validation and improvement
http://www.nist.gov/el/building_environment/heattrans/upload/netzerofinal.pdf

37. NIST nZEH Test Facility-its Unique
Features
http://www.nist.gov/el/building_environment/heattrans/upload/netzerofinal.pdf

38. NZEB Database from DOE
LEED Platinum
LEED Platinum
LEED Platinum
LEED Platinum
• Source: http://zeb.buildinggreen.com/
• 10 projects from DOE Zero Energy Buildings database
• Building types include: commercial offices, recreation, education/lab,
residential, interpretive center and retail
• Some of them are also LEED platinum rating and HERS level 0

39. Technologies Available for NZEB
Source: http://www.ecofuturesbuilding.com/learn-zero/what-is-zero-net-energy/

40. Summary of the Main Technologies for
NZEB
Proven technologies Still developing
technologies
Technologies on the
horizon
Thermal
insulation
Low conductivity
materials; Reflective
materials
Reflective roofs;
green roofs;
exploring new
materials for thermal
insulation
Smart reflective roofs; cool
colored paints (with IR
reflective pigments); nano
materials for thermal
insulation; highly insulation
façade systems
Windows Multi-layer windows;
Low-e glazing; gas filled
air gaps; thermal break
frames
Glazings with
dynamic properties
(e.g.
electrochromics)
BIPV glazings; solar
glazing; solar curtain walls
Lighting CFL; LED; daylight
harvest through
transparent envelope
CFL; LED;
intelligent, dynamic
and/or light-
redirecting facades
with automated
lighting controls
Intelligent natural
daylighting distributing
systems
Source: Maria Kapsalaki & Vitor Leal (2011): Recent progress on net zero energy buildings, Advances in Building
Energy Research, 5:1, 129-162

41. Summary of the Main Technologies for NZEB
Proven technologies Still developing
technologies
Technologies on the horizon
Heating and
cooling
equipment
Condensing gas boilers;
biomass boilers; high
EER chillers and heat
pumps (ground and air
source)
Micro CHP Solar CHP; thermally activated
HP; TE cooling; frostless HP;
distributed refrigeration/water-
source HP
Ventilation Mixed mode natural and
mechanical with heat
recovery (HR); nightly
cooling; stack effect
ventilation
Hybrid ventilation systems
with automatic controls;
displacement ventilation
Heat recovery windows;
personalized ventilation
Renewable
technologies
Thermal solar; biomass
heating; PV systems;
PV thermal solar
systems; air solar
collectors
PV systems (increased
efficiency); PV thermal
solar systems
BIPV systems, wind turbines
(WT) and micro WT
Building energy
management
systems
Sensors; energy control
(zone heating and
cooling) and monitoring
systems
Monitoring and control
systems running on IP
communication
infrastructure
Improved management
systems with grid/consumer
supply-demand integration
Source: Maria Kapsalaki & Vitor Leal (2011): Recent progress on net zero energy buildings, Advances in Building
Energy Research, 5:1, 129-162

42. ZEB Renewable Energy Options
Option Number
(Hierarchy)
ZEB Supply-Side Options Examples
0 Reduce site energy use low-
energy building technologies
Daylighting, high-eff. HVAC equip.,
natural ventilation, evaporative cooling…
On-site Supply Options
1 Use renewable energy sources
within the building’s footprint
PV, solar hot water, and wind located on
the building
2 Use renewable energy sources
available at the site
PV, solar hot water, low-impact hydro,
and wind located on-site, but not on the
building
Off-site Supply Options
3 Use renewable energy sources
available off site to generate
energy on site
Biomass, wood pellets, ethanol…
4 Purchase off-site renewable
energy sources
Utility-based wind, PV, emissions
credits, other “green” purchasing
options
Highly
preferred
preferred
Source: Torcellini et al., 2006, Zero energy buildings: a critical look at the definition, ACEEE Summer Study, Aug. 14-
18, Pacific Gove, CA

43. Technology Penetration
Data is collected based on a database of 60 net zero energy/ net zero
energy capable commercial buildings
Source: Getting to zero 2012 status update: a first look at the costs and features of zero energy commercial
buildings, New Building Institute research report, March 2012

44. Solar Curtain Wall
Source: Case study: solar curtain wall, Konarka, Aug. 2011

45. Building Integrated Wind Turbines
Source: http://www.mymodernmet.com/profiles/blogs/what-big-wind-turbines-you;
http://sustainability.yale.edu/sites/default/files/bec3.jpg
Wind turbines in World Trade Center,
Bahrain
Micro wind turbines in Yale Univ.

46. Cost/Performance Curve
Source: Anderson R. and Roberts D., Maximizing Residential Energy Savings: Net Zero Energy Home Technology
Pathways, NREL/TP-550-44547

47. Previous ThermCom Development
47

48. 48
Max Tech and Beyond: Ultra-Low
Energy Use Appliance Design
Competition for 2011-2012

49. SSLCAC Design Overview
Radiative Heat Exchanger: Cooling Wall
49

50. Other examples

51. Net Zero Homes
Sep. 2010 R.
Radermacher
51
Net Zero home - Ft. Worth, Texas

52. Net Zero Homes
Sep. 2010 R.
Radermacher
52Net Zero “Beach House” - California

53. Net Zero Homes
Sep. 2010 R.
Radermacher
53Net Zero - Chicago

54. Net Zero Homes
Sep. 2010 R.
Radermacher
54Net Zero – Staplehurst, England

55. Net Zero Homes
Sep. 2010 R.
Radermacher
55
“Cannon Beach Residence”
Oregon coast

56. Net Zero Homes
• LEED Platinum
• Currently holds
highest rating
for a Net Zero
residence in
the US
• Produces 40%
more energy
than it
consumes
Sep. 2010 R.
Radermacher
56
Yannell Residence, Illinois

57. Belgian NZE station at Antartica

58. Sustainable Homes