U.S. Department of Energy

Building Technologies Office

Commercial Buildings Integration

A Common Definition for Zero 

Energy Buildings

Date: 2014-11-26

Version: Public Comment Period Draft
ZEB Definitions Report – Public Comment Version Page 1 of 15

2014-11-26

Table of Contents

Introduction ..................................................................................................................................................2

Background ...............................................................................................................................................2

Goals .........................................................................................................................................................2

Methodology.............................................................................................................................................2

Acknowledgements...................................................................................................................................3

ZEB Definition Guiding Principles..................................................................................................................4

Zero Energy Building Definitions...................................................................................................................4

Zero Energy Building (ZEB)........................................................................................................................4

Zero Energy Campus.................................................................................................................................4

Zero Energy Portfolio ................................................................................................................................4

Zero Energy Community ...........................................................................................................................4

Nomenclature ...............................................................................................................................................4

Measurement and Implementation Guidelines............................................................................................5

Boundaries................................................................................................................................................5

Energy Accounting and Measurements....................................................................................................6

Source Energy Calculations.......................................................................................................................7

Using “Zero Energy Building” ....................................................................................................................9

Additional Consideration Under Review...................................................................................................9

Appendix 1 – Research Materials ...............................................................................................................11

Appendix 2 – Subject Matter Experts.........................................................................................................13

Appendix 3 – Stakeholder Workshop Participants .....................................................................................14
ZEB Definitions Report – Public Comment Version Page 2 of 15

2014-11-26

Introduction

This Report has been prepared by the National Institute of Building Sciences (Institute) for the U.S. 

Department of Energy, Building Technologies Office (DOE). The Report summarizes the process 

employed and outcomes developed for defining identifying zero energy buildings.

Background

Zero Energy Buildings (ZEBs) have a tremendous potential to transform the way buildings use energy 

and there is an increasing number of buildings meeting this goal. Private commercial property owners 

are interested in developing zero energy buildings to meet their corporate goals and some, have already 

constructed buildings designed to be zero energy. In response to regulatory mandates, federal 

government agencies and many state and local governments, are beginning to move toward targets for 

zero energy buildings. However, there is little consensus on what it means to have a zero energy 

building: definitions differ from region to region and from one building professional to another. 

Goals

A broadly accepted definition of ZEB boundaries and metrics is foundational to efforts by governments, 

utilities, or private entities to recognize or incentivize zero energy buildings. A commonly accepted 

definition and corresponding methods of measurement for zero energy buildings would also have a 

significant impact on the development of design strategies for buildings and help spur greater market 

uptake of such projects.

To be effective and accepted definitions of ZEBs need to include clear and concise language. Metrics 

and measurement guidelines should be defined to allow verification of the achievement of the key 

elements of the definition. The definitions, metrics and guidelines should address how energy 

consumption is measured and what energy uses and types to include in its determination. 

Methodology

Creating a broadly agreed upon and supported definition of ZEB should involve participation from the 

many organizations that have a stake in the outcome. The National Institute of Building Sciences

(Institute), a non-profit, non-governmental organization was selected by DOE to accomplish this task. 

The Institute was established by the U.S. Congress, to bring together representatives of government, the 

professions, industry, labor and consumer interests, and regulatory agencies to focus on the 

identification and resolution of problems and potential problems that hamper the construction of safe, 

affordable structures throughout the United States. 

The Institute’s High Performance Building Council (HPBC), formed in April 2007 in response to Section 

914 of the Energy Policy Act, is leading the process to develop commonly agreed upon definitions for 

zero energy buildings. The HPBC, with representatives from most of the major standards writing 

organizations, industry trade associations, nonprofit organizations, and federal government entities 

involved with the built environment, has representation from all members of the building team from 

designers to constructors to owners.

Early in 2014, the Institute, with funding and support from the DOE Building Technologies Office began, 

working through the HPBC, to establish a common national ZEB definition. The Institute, with input from 

DOE, formed the project team identified in the acknowledgements section. A full list of issues to be 

addressed and a draft set of definitions and metrics were developed by the project team during the 

research phase of the project through surveying existing publications (see Appendix 3 for a list of 

publications researched) and interviewing subject matter experts (SMEs) (see Appendix 2 for a list of 
ZEB Definitions Report – Public Comment Version Page 3 of 15

2014-11-26

SME interviewed) working on zero buildings from across the building industry. These findings were 

presented to the stakeholders (see Appendix 3 for a list of stakeholder organizations) involved with the 

creation and advancement of zero energy buildings and who were invited to participate by the HPBC to 

contribute their perspective and provide their input. 

The team studied the basic issue of what to call buildings that are designed and operated in such a way 

that energy consumption is reduced to a level that it is balanced by renewable energy production over a 

typical one-year period. To make the determination, definitions already in use were reviewed; the 

opinions of SME and Stakeholders were collected; and other DOE programs and goals were considered. 

A key consideration was feedback received by the DOE Zero Energy Ready Homes program that 

concluded the term “net” was confusing to consumers. The desire was to have a term that resonated

with building owners and that is technically correct. The idea advanced by some that “net” is necessary 

to be accurate in accounting for energy usage was considered. The conclusion reached was that the 

word “net” did not add any substantive meaning to the name, since the definition describes how to 

account for imported and exported energy. Therefore, in striving for simplicity and to accentuate the 

core objective, use of the term “Zero Energy Building (ZEB)” is being proposed. 

The “ZEB Definitions and Nomenclature” that follow are based on the commentary received at the 

Workshop. These are being provided to the SMEs and Stakeholders for review and commentary, prior to 

being made available for a public comment period. After all feedback has been received and reviewed, 

the final version will be produced. 

The need for additional definitions for related groupings of buildings was identified in the process. 

Definitions for “zero energy campuses,” “zero energy communities” and “zero energy portfolios” are all 

included here to expand the reach of the ZEB concept, to provide for the collective generation of 

renewables and to account for different energy needs of buildings. 

The goal is to achieve a commonly agreed upon definition of ZEB with supporting Nomenclature and 

Guidelines to facilitate their use, and to set a bar for achieving a ZEB that can be relevant into the future. 

The results will be published by the HPBC and made available to government and industry to support 

the developing demand for zero energy buildings.

Acknowledgements

The Zero Energy Building definitions, nomenclature and guidelines have been developed through the 

efforts of the following project team members.

Sonia Punjabi U.S. Department of Energy, Building Technologies Office

Paul Torcellini National Renewable Energy Laboratory

Richard Diamond Lawrence Berkeley National Laboratory

Roger Grant National Institute of Building Sciences (NIBS)

Ryan Colker National Institute of Building Sciences (NIBS)

Kent Peterson P2S Engineering, NIBS Consultant

Get Moy AECOM, NIBS High Performance Building Council

Earle Kennett National Institute of Building Sciences (NIBS)

The Project Team was greatly assisted by the SMEs, identified in Appendix 2, who were interviewed 

during the research phase of the project; as well as by the Stakeholder Workshop Participants identified 

in Appendix 3.
ZEB Definitions Report – Public Comment Version Page 4 of 15

2014-11-26

ZEB Definition Guiding Principles

Based on the following guiding principles, a commercial zero energy building (ZEB) definition should:

1. Create a standardized basis for identification of ZEBs for use by industry.

2. Be capable of being measured and verified, and should be rigorous and transparent.

3. Influence the design and operation of buildings to substantially reduce building operational 

energy consumption.

4. Be clear and easy to understand by the industry and policy makers.

5. Set a long-term goal and be capable of being in place without change for some time into the 

future.

Zero Energy Building Definitions

The base definition of a zero energy building follows. The bold text represents key items that are further

addressed with definitions and guidelines.

Zero Energy Building (ZEB) 

An energy-efficient building where the actual annual source energy consumption is balanced by on-site 

renewable energy.

In addition to the base definition of a ZEB that includes all renewable energy on or adjacent to the 

building, the need for definitions to accommodate collections of buildings was clearly evident. To meet 

this need, the following variations on the base ZEB definition are provided. All Guidelines for the base 

ZEB apply unless noted otherwise or expanded upon in the Guidelines section that follows.

Zero Energy Campus

An energy-efficient campus where the actual annual source energy consumption is balanced by on-site 

renewable energy.

Zero Energy Portfolio

An energy-efficient portfolio where the combined actual annual source energy consumption is 

balanced by on-site renewable energy.

Zero Energy Community

An energy-efficient community where the actual annual source energy consumption is balanced by onsite renewable energy.

Nomenclature

This nomenclature provides definitions of key terms applied to the Zero Energy definitions.

Annual: covering at least one period of 12 consecutive months.

Building: a structure wholly or partially enclosed within exterior walls, or within exterior and party walls, 

and a roof, affording shelter to persons, animals, or property. [ASHRAE 105-2014]

Building energy: energy consumed by a building or at the building site as measured at the site 

boundary. At minimum, this includes heating, cooling, ventilation, domestic hot water, indoor and 

outdoor lighting, plug loads, process energy, and transportation within the building.
ZEB Definitions Report – Public Comment Version Page 5 of 15

2014-11-26

Campus: a site made up of a collection of related building sites owned by a given institution.

Community: a group of building sites that has a particular characteristic in common. For the purpose of 

zero energy building, the common characteristic is the desire to share the benefit(s) of local renewable 

energy production systems.

Delivered energy: any viable type of energy that could be bought or sold for use in the building, 

including electricity, steam, hot water or chilled water, natural gas, biogas, landfill gas, coal, coke, 

propane, petroleum and its derivatives, residual fuel oil, alcohol based fuels, wood, biomass, and any 

other material consumed as fuel.

Energy: the capacity for doing work. Energy takes a number of forms that may be transformed from 

one into another, such as thermal (heat), mechanical (work), electrical, or chemical. Customary 

measurement units are British thermal units (Btu), Joules (J), or kilowatt-hours (kWh).

Exported energy: on-site renewable energy supplied through the site boundary and used outside the 

site boundary.

On-site renewable energy: on-site renewable energy includes any renewable energy source harnessed 

within the site boundary that could be used by the building and/or could be exported outside the site 

boundary.

Portfolio: a collection of buildings owned by a single organization.

Renewable energy: energy resources that are naturally replenishing but flow-limited. They are virtually 

inexhaustible in duration but limited in the amount of energy that is available per unit of time. 

Renewable energy resources include biomass, hydro, geothermal, solar, wind, ocean thermal, wave 

action, and tidal action. [DOE EIA Glossary]

Site boundary: a fixed boundary that includes within it all areas associated with the building(s) (both 

inside and outside of the building) where energy is used and produced.

Source energy: delivered energy plus the energy required to extract, convert, and transmit the energy 

to the site boundary.

Measurement and Implementation Guidelines

The guidelines identify the methodology for establishing boundary conditions, conducting energy 

measurements and achieving energy balances that support applying the Zero Energy Building, Zero 

Energy Campus, Zero Energy Portfolio, and Zero Energy Community definitions. The guidelines address:

• Measurement boundaries for all definitions

• Energy accounting and measurements

• Source energy calculations

Boundaries

The definitions require the use of a defined site boundary. The site boundary represents a meaningful 

boundary that is functionally part of the building(s). For a single building on a single property, the site 

boundary is typically the property boundary. The site boundary should include the point of utility 

interface. Figure 1 shows the site boundary of site energy and how it forms from building energy, on 

site renewable energy production, delivered energy and exported energy.
ZEB Definitions Report – Public Comment Version Page 6 of 15

2014-11-26

Figure 1 – Site Boundary of Energy Transfer for Zero Energy Accounting

The site boundary for a Zero Energy Building (ZEB) could be around the building footprint if the on-site 

renewable energy is located within the building footprint. The boundary could be around the building 

site if some of the on-site renewable energy is on-site but not within the building footprint.

The site boundary for a Zero Energy Campus allows for the building sites on a campus to be aggregated 

so that the combined on-site renewable energy could offset the combined building energy from the 

buildings on the campus. The site boundary for a Zero Energy Community or Zero Energy Portfolio 

would allow a group of project sites at different locations to be aggregated so that the combined on-site 

renewable energy could offset the combined building energy from the aggregated project sites. Zero 

Energy Communities can share the benefit of an off-site shared renewable energy project that pools 

investments from multiple building owners in a community and provides power benefits in return.

The renewable energy produced on site is taken into account if it reduces the amount of delivered 

energy needed and and/or is exported if not used in the building(s) i.e., on-site production is not 

considered as part of delivered energy on site.

Energy Accounting and Measurements

A Zero Energy Building is typically a grid-connected building that is very energy efficient. The premise is 

that zero energy buildings use the electric grid or other systems to transfer any surplus of on-site 

renewable energy to other users.
ZEB Definitions Report – Public Comment Version Page 7 of 15

2014-11-26

Energy accounting for a ZEB would include energy used for heating, cooling, ventilation, domestic hot 

water, indoor and outdoor lighting, plug loads, process energy, and transportation within the building. 

Vehicle charging energy for transportation inside the building would be included in the energy 

accounting. Vehicle charging energy for transportation outside the building would be excluded from the 

energy accounting. Delivered and exported energy is measured at the site boundary.

A ZEB balances its energy use so that the energy exported to the grid or other energy network (i.e.,

campus or facility) is equal to or greater than the energy delivered to the building. A ZEB may only use 

on-site renewable energy in offsetting the delivered energy. On-site renewable energy is energy 

produced from renewable energy sources within the site boundary. Renewable fuels are not included in 

this term, because they are treated as delivered energy to the building, i.e. off-site renewables. Nonrenewable energy that is exported from the site boundary is not allowed to offset delivered energy.

Annual balance of zero source energy use typically leads to the situation where significant amount of the 

on-site renewable energy generation would be exchanged with the grid. Therefore, a ZEB produces onsite renewable energy when conditions are suitable and uses delivered energy during the rest of the 

time.

Delivered energy to the building includes grid electricity, district heat and cooling, renewable and nonrenewable fuels. 

On-site renewable energy production systems may supply building energy, thus reducing the need for 

the delivered energy to the building, or may be directly exported to energy networks. This is taken into

account in the net delivered energy balance. Zero Energy Campuses, Portfolios and Communities can 

combine the on-site renewable energy among different sites under an aggregated site boundary to 

balance the delivered energy.

The annual net energy balance can be measured with the use of appropriate energy metering 

devices. Energy meters provide the basis for buildings to document the quantity of energy used by the 

site and the quantity of on-site renewable energy generation. These meters may include utility meters 

that track purchased energy usage, meters specifically measuring onsite renewable energy generation 

that is exported, or "net" meters that measure both purchased energy and onsite renewable energy 

exported and calculate the difference.

Source Energy Calculations

Most building managers are familiar with site energy, the amount of energy consumed by a building as 

reflected in utility bills. Site energy may be delivered to a facility in one of two forms: primary and/or 

secondary energy. Primary energy is the raw fuel that is burned to create heat and electricity, such as 

natural gas or fuel oil used in on-site generation. Secondary energy is the energy product (heat or 

electricity) created from a raw fuel, such as electricity purchased from the grid or heat received from a 

district steam system. A unit of primary and a unit of secondary energy consumed at the site are not 

directly comparable because one represents a raw fuel while the other represents a converted fuel. 

Therefore, to assess the relative efficiencies of buildings with varying proportions of primary and 

secondary energy consumption, it is necessary to convert these two types of energy into equivalent 

units of raw fuel consumed to generate that one unit of energy consumed on-site. To achieve this 

equivalency, the convention of source energy is utilized. 

When primary energy is consumed on site, the conversion to source energy must account for losses that 

are incurred in the storage, transport, and delivery of fuel to the building. When secondary energy is 

consumed on site, the conversion must account for losses incurred in the production, transmission, and 

delivery to the site. The factors used to restate primary and secondary energy in terms of the total 
ZEB Definitions Report – Public Comment Version Page 8 of 15

2014-11-26

equivalent source energy units are called the source-site energy ratios. The Zero Energy definition uses 

national average ratios to accomplish the conversion to source energy because the use of national 

average source-site ratios ensures that no specific building will be credited (or penalized) for the relative 

efficiency of its energy provider(s).

Source energy is calculated from delivered and exported renewable energy for each energy type using

source-site energy ratios. Source-site energy ratios are applied to convert each kBtu of energy delivered 

and exported on site into the total kBtu of equivalent source energy. The source-site energy ratios 

utilized are from EPA ENERGY STAR1 with the single exception of on-site renewable electricity, which is 

the same electrical value for delivered and exported energy. Table 1 summarizes the national average 

source-site energy ratios for various energy types.

Energy Type

ENERGY STAR

Source-Site Ratio, r

Electricity 3.14

Natural Gas 1.05

Fuel Oil (1,2,4,5,6,Diesel, Kerosene) 1.01

Propane & Liquid Propane 1.01

Steam 1.20

Hot Water 1.20

Chilled Water 1.00

Wood 1.0

Coal/Coke 1.0

Table 1 – National Average Source-Site Energy Ratios

Source energy would be calculated using the following formula:

Esource = ∑i(Edel,irdel,i) − ∑i(Eexp,irexp,i)

Where

Edel,iis the delivered energy for energy type i;

Eexp,iis the exported on-site renewable energy for energy type i;

rdel,iis the source-site energy ratio for the delivered energy type i;

rexp,iis the source-site energy ratio for the exported energy type i;

 

1

ENERGY STAR Portfolio Manager Technical Reference: Source Energy, EPA, July 2013
ZEB Definitions Report – Public Comment Version Page 9 of 15

2014-11-26

Using “Zero Energy Building”

The designation Zero Energy Building should be used only for buildings that have demonstrated through 

actual annual measurements that the on-site renewable exported energy is greater than or equal to the 

delivered energy through the site boundary. Buildings that have been designed to be zero energy, but 

have not yet had a full year of operation demonstrating that they meet the requirements, are 

encouraged to identify their intent to be a Zero Energy Building.

Additional Considerations Under Review

1. The potential value of a definition for a Zero Energy Building that uses Renewable Energy Credits 

(RECs) to balance actual annual source energy consumption is under consideration. According to 

the EPA: “A REC represents the property rights to the environmental, social, and other non-power 

qualities of renewable electricity generation. A REC, and its associated attributes and benefits, can 

be sold separately from the underlying physical electricity associated with a renewable-based 

generation source.”

Multi-story buildings occupying entire lots, especially those located in urban areas may use off-site 

renewable energy or purchase RECs to balance their source energy consumption. For similar 

reasons, urban ZEB portfolios and urban ZEB campuses may want to purchase RECs if on-site 

renewable generation is limited due to physical constraints. These buildings cannot claim ZEB status 

as defined in this document, but could possibly be recognized as REC-Zero Energy Buildings (RECZEB). Renewable energy certificates (RECs) may provide large urban buildings with an avenue to 

address their energy consumption beyond what they could achieve with onsite generation alone. 

The project team is still evaluating the possible value of a REC-ZEB definition and is seeking specific 

comments on the following draft definition to help determine if it should be incorporated into this 

report:

REC-ZEB: an energy-efficient building where the actual annual source energy consumption is 

balanced by on-site renewable energy production to the maximum extent possible and then 

utilizes Renewable Energy Credits (RECs) from certified sources to make up the difference in 

renewable energy required to achieve a ZEB level.

Esource = [(200,000kBtu × 3.14) + (60,000kBtu × 1.0) + (100,000 × 1.05)]

− (260,000kBtu × 3.14)

= 793,000kBtu − 816,400kBtu

= −23,400kBtu

Example Calculation

A building has the following delivered energy types: 200,000 kBtu electricity, 60,000 kBtu chilled 

water, and 100,000 kBtu natural gas. The on-site renewable exported energy is 260,000 kBtu 

electricity from photovoltaics. (Note: The equation is using energy transferred across the site 

boundary and does not include on-site renewable energy consumed by the building.) 

Using the formula above, the annual source energy balance would be:

Since Esource ≤ 0, the building would be a Zero Energy Building.
ZEB Definitions Report – Public Comment Version Page 10 of 15

2014-11-26

2. There is interest in the concept of Zero Energy Ready (ZER) buildings. Essentially a ZER building is a 

highly energy efficient building that could conceivably become a ZEB in the future with the addition 

of renewable energy. While this is an interesting and popular concept, due to the number of 

variables involved, a methodology for establishing what constitutes a ZER building was not readily 

identifiable. Consequently, it has not been defined in this Report. However, comments on the need 

for a common definition and measurement guidelines for ZER buildings, to accompany the definition 

of a ZEB, are welcomed.
ZEB Definitions Report – Public Comment Version Page 11 of 15

2014-11-26

Appendix 1 – Research Materials

NZEB/NZERB Publications, Reports and Other Resources

2014-06-10

Resource Description Author(s) Publisher Pub. Date

2014 Getting to Zero Status Report The research report is a look at the projects, policies and 

programs driving zero net energy performance in 

commercial buildings. It examines the numbers, locations, 

types, ownership, and policy and program drivers for ZNE.

Cathy Higgins, Amy Cortese, Mark Lyles New Buildings Institute 2014-01

ANSI/ASHRAE Standard 105-2014 Standard Methods of Determining, Expressing, and 

Comparing Building Energy Performance and Greenhouse 

Gas Emissions

ASHRAE ASHRAE 2014-01

ASHRAE Vision 2020 Describes the vision held by members of the American 

Society of Heating, Refrigerating and Air-Conditioning 

Engineers of a future when buildings will produce as much 

energy as they use. These are net zero energy buildings 

(NZEBs). We believe such buildings can be market-viable 

by the year 2030.

ASHRAE 2020 Ad Hoc Committee ASHRAE 2008-01

Clean Energy Trends 2014 Review of developments in clean energy in 2013 including 

section on Net Zero Energy Buildings Gaining Ground.

Ron Pernick, Clint Wilder, James Belcher Clean Edge 2014-03

Definition of a "Zero Net Energy" Community This paper begins with a focus solely on buildings and 

expands the concept to define a zero-energy community, 

applying the ZEB hierarchical renewable classification 

system to the concept of community.

Nancy Carlisle, Otto Van Geet, Shanti Pless NREL 2009-11

DOE Challenge Home Why Zero Energy Ready is Readily Achievable:

Technical Specifications for DOE Challenge Home

Overview of Department of Energy Challenge Home 

Program and requirements for creating Zero Energy Ready 

Homes.

Jamie Lyons Department of Energy 2010-02

Energy Star Portfolio Manager Technical 

Reference: Source Energy

Evaluation of Source vs. Site Energy as metric for 

meausuring energy use by a building.

U.S. Environmental Protection Agency U.S. Environmental 

Protection Agency

2013-07

Getting to Net Zero The intent of this article is to provide an overview of the 

DOE’s efforts toward realizing cost-effective net-zero 

energy buildings (NZEBs).

Drury Crawley, Shanti Pless, Paul Torcellini NREL/ASHRAE Jouurnal 2009-09

Getting to Zero Final Report of the Massachusetts Zero Net Energy 

Buildings Task Force

Massachusetts Zero Net Energy Buildings 

Task Force

Massachusetts Zero Net 

Energy Buildings Task 

Force

2009-03

Living Building Challenge 2.1 Description of the Living Building Challenge program 

including a definition and measurement system for Net 

Zero Energy Buildings.

International Living Futures Institute International Living Futures 

Institute

2012-05

Main Street Net-Zero Energy Buildings: The Zero 

Energy Method in Concept and Practice

Discussess ways to achieve large-scale, replicable NZEB 

performance. Many passive and renewable energy 

strategies

are utilized, including full daylighting, high-performance 

lighting, natural ventilation through operable windows, 

thermal mass, transpired solar collectors, radiant heating 

and cooling, and workstation configurations to maximize 

daylighting.

Paul Torcellini, Shanti Pless, Chad Lobato, 

Tom Hootman

ASME 2010 4th International 

Conference on Energy 

Sustainability

2010-05

Net Zero and Living Building Challenge Financial 

Study: A Cost Comparison Report for Buildings in 

the District of Columbia

The purpose of the Net Zero and Living Building Challenge 

Financial Study: A Cost Comparison Report for Buildings 

in the District of Columbia was twofold. First, to investigate 

costs, benefits and approaches necessary to improve 

building performance in the District of Columbia from LEED

Platinum to zero energy, zero water and Living Building 

status. Second, to advise District government on policy 

drivers related to deep green buildings and to analyze the 

opportunities for the District to offer incentives to advance 

most rapidly toward zero energy, zero water and Living 

Buildings.

International Living Futures Institute

New Buildings Institute

Skanska

District Department of the 

Environment

2014-02

Net Zero Blueprint This article presents the process used for delivering the 

RSF as a replicable blueprint to achieve a large reduction 

in building energy use and to adopt a net zero energy 

approach for large-scale commercial buildings without 

increasing cost.

TOM HOOTMAN; DAVID OKADA.; SHANTI 

PLESS; MICHAEL SHEPPY; AND PAUL 

TORCELLINI

NREL/ASHRAE High 

Performance Buildings 

Journal

2012-11

Net Zero Energy Buildings Book Karsten Voss, Eike Musall Detail Green Books 2013-02

Net Zero Energy Buildings Page on WBDG with overview including links to related 

resources and publications - 

http://www.wbdg.org/resources/netzeroenergybuildings.php 

Steven Winter Associates Whole Building Design Guide 2013-09

Net Zero Energy Buildings White Paper White Paper on Sustainability to inspire architects, 

engineers, contractors, building owners, developers, 

building product manufacturers, environmentalists, 

policymakers, government officials, corporate executives, 

officeholders, and the public to foster the development of 

net-zero energy buildings and homes.

Rob Cassidy, Editor with various chapter 

authors

Building Design & 

Construction

2011-03

Net-Zero Energy Buildings: A Classification 

System Based on Renewable Energy Supply 

Options

A classification system for NZEBs based on the renewable 

sources a building uses.

Shanti Pless, Paul Torcellini NREL Technical Report 2010-06
ZEB Definitions Report 

– Public Comment Version Page 12 of 15

2014-11-26

NZEB/NZERB Publications, Reports and Other Resources

2014-06-10

Resource Description Author(s) Publisher Pub. Date

Pursuit of Net Zero: The Walgreens Experience Webinar on Walgreen's experience with developing and 

operating a net zero store in Chicago, IL.

Jamie J. Meyers Energy Center of Wisconsin 2014-03

The Technical Feasibility of Zero Net Energy 

Buildings in California

This study is a forward-looking "stress test" of the Zero Net 

Energy (ZNE) new construction goals set forth by 

California's enegy angecies. This study asesses the 

potential performance of best-in-class building desings in 

2020 for both residential and commercial structures.

ARUP. Davis Energy Group, Sun Light & 

Power, New Builidngs Institute, Engineering 

350, Sustainable Design + Behavior

Pacific Gas & Electric 

Company

2012-12

Toward Fully Functional Net Zero Buildings: An 

Engineering Perspective

In this article, current concepts of NZEB are analyzed; an 

operational definition (OZEB) of “Net-Zero Energy 

Commercial Buildings” is proposed; a design approach 

toward achieving site-specific OZEBs is presented; and 

examples of evidence-based results are reviewed and 

Boggarm S. Setty, James E. Woods Unpublished, pending review 2014-04

Zero Energy Buildings: A Critical Look at the 

Definition

This study shows the design impacts of the definition used 

for ZEB and the large difference between definitions. It also 

looks at sample utility rate structures and their impact on 

the zero energy scenarios.

Paul Torcellini, Shanti Pless, and Michael 

Deru, National Renewable Energy Laboratory

Drury Crawley, U.S. Department of Energy

NREL 2006-06

European 

How to define nearly net zero energy buildings 

nZEB

A technical definition for nearly zero energy buildings 

required in the implementation of the Energy performance 

of buildings directive recast. Energy calculation framework 

and system boundaries associated with the definition are 

provided to specify which energy flows in which way are 

taken into account in the energy performance assessment.

Jarek Kurnitski, Francis Allard, Derrick 

Braham, Guillaume Goeders, Per Heiselberg, 

Lennart Jagemar, Risto Kosonen, Jean 

Lebrun, Livio Mazzarella, Jorma Railio, Olli 

Seppänen, Michael Schmidt, Maija Virta

REHVA Journal 2011-05

Nearly-zero, Net zero and Plus Energy Buildings The topic of Zero Energy Buildings (ZEBs) has received 

increasing attention in recent years, up to inclusion in 

strategic energy policy papers in several countries. 

However, despite the emphasis placed on the goals, the 

various ZEB definitions applied mostly remain generic and 

are not yet standardised.

Karsten Voss, Igor Sartori, Roberto Lollini REHVA Journal 2012-12

Principles for Nearly Zero-Energy Buildings The study builds on existing concepts and building 

standards, analyses the main methodological challenges 

and their implications for the nZEB definition, and compiles 

a possible set of principles and assesses their impact on 

reference buildings. Subsequently the technological, 

financial and policy implications of these results are 

evaluated. Finally, the study concludes by providing an 

outlook on necessary further steps towards a successful 

implementation of nearly Zero-Energy Buildings.

Thomas Boermans, Andreas Hermelink, 

Sven Schimschar, Jan Grözinger, Markus 

Offermann, Kirsten Engelund Thomsen, 

Jørgen Rose, Søren O. Aggerholm

Building Performance 

Institute Europe (BPIE)

2011-11

Technical definitions for nearly zero energy buildingsREHVA has revised its nZEB technical definition, since 

now the only available methodology suitable for the 

implementation in national building codes for the primary 

energy indicator

calculation. The 2013 version was prepared in cooperation 

with European standardization organization CEN and it 

replaces 2011 version with the intention to help the experts 

in the

Member States to define the nearly zero energy buildings 

in a uniform way. 2013 version is complemented with 

specifications for nearby renewable energy and for the 

contribution of

renewable energy use. A set of the system boundaries and 

equations are given for energy need, energy use, delivered 

and exported energy, primary energy and for renewable 

energy

ratio calculation. With these definitions and energy 

calculation framework, primary energy indicator and 

renewable energy ratio can be calculated as required by 

the directive.

Calculation principles are explained with worked examples 

in order to assure uniform understanding of the definitions.

Jarek Kurnitski REHVA Journal 2013-05

Towards nealy zero-energy buildings: Definition of 

common principles under the EPBD

The project supports the European Commission in its 

activities to:

Give guidance to Member Sates on how to interpret 

requirements for nearly zero energy buildings.

Develop a common reporting format on nearly zero energy 

buildings to be used by MS and evaluate the adequacy of 

measures and activities reported by MS in their national 

plans on nearly zero energy buildings.

Link cost optimality and the nearly zero energy buildings 

principle in a consistent way and facilitate their 

convergence until 2021.

Andreas Hermelink, Sven Schimschar, 

Thomas Boermans, Lorenzo Pagliano, Paolo 

Zangheri, Roberto Armani, Karsten Voss, 

Eike Musall

Ecofys: Politecnico di 

Milano / eERG: University of Wuppertal

2013-02
ZEB Definitions Report – Public Comment Version Page 13 of 15

2014-11-26

Appendix 2 – Subject Matter Experts

The following individuals were interviewed during the research phase of the project and their responses 

used to formulate the definitions and supporting materials. Their review and input also contributed to

subsequent versions.

Organization SME Category

1 Whole Foods Kathy Loftus Commercial 

Owner

2 Walmart Stores, Inc. James McClendon, PE Commercial 

Owner

3 Integral Group John Andary, PE, LEED AP Design 

4 David Kaneda, PE, FAIA, LEED AP BD+C Consultant

5 Peter Rumsey Peter Rumsey, PE, FASHRAE, CEM, LEED 

AP

Design 

Consultant

6 Architecture Interiors Planning Urban 

Design

Scott Shell, FAIA LEED AP BD+C Design 

Consultant

7 Indoor Environments Consultant James Woods, Ph.D., P.E. Design 

Consultant

8 US Army Ft. Carson Colorado Hal Alguire Federal 

Mark Hunsiker Owner

Joe Wyka

9 U.S. General Services Administration

Office of Chief Greening Officer

Kevin Powell Federal 

Owner

10 Building Design & Construction Rob Cassidy Media

11 Building Green/Green Source/ 

Environmental Building News

Nadav Malin Media

12 Lawrence Berkeley National Laboratory Rick Diamond National 

Laboratory

13 National Renewable Energy Laboratory Shanti Pless, LEED AP National 

Laboratory 14 Paul Torcellini

15 National Institute of Building Sciences Ryan Colker, JJD NGO

16 Passive House Institute U.S. Walter Grondzik, PE, LEED AP NGO

17 Daikin Applied/ASHRAE Rick Hermans, PE, HFDP NGO

18 New Buildings Institute Dave Hewitt NGO

Cathy Higgins

19 International Living Futures Institute Brad Liljequist, AICP, LEED AP NGO

20 Architecture2030 Edward Mazria NGO

21 AECOM, Inc.

High Performance Building Council

Get W. Moy, P.E, LEED AP NGO

22 Green Building Initiative Jerry Yudelson, PE, LEED Fellow NGO

23 Pacific Gas & Electric Peter Turnbull Utility
ZEB Definitions Report – Public Comment Version Page 14 of 15

2014-11-26

Appendix 3 – Stakeholder Workshop Participants

The following individuals participated in the Defining Zero Energy Buildings Stakeholders Workshop June 17, 2014 

providing their input to the research and resulting draft definitions and nomenclature presented at the Workshop

and providing comments on the revised definitions, guidelines and supporting materials after the Workshop.

Name Organization

Brian Castelli Alliance to Save Energy

Harry Misuriello American Council for an Energy Efficient Economy

Pamel Sams American Institute of Architects

Daniel Lapato American Public Gas Association

Tanzina Islam American Public Power Association

Edward Mazria Architecture 2030

Vincent Martinez Architecture 2030

Doug Read ASHRAE

Ron Burton Building Owners and Managers Association International

Paul Bertram Business Council for Sustainable Energy

Bill Updike District of Columbia Department of the Environment

Daniel White District of Columbia Department of the Environment

Steve Rosenstock Edison Electric Institute

Neil Leslie Gas Technology Institute

Jeff Johnson International Facility Management Association

Brad Liljequist International Living Future Institute

Patrick Hughes National Electrical Manufacturers Association 

Sandy Fazeli National Association of State Energy Officials

Ryan Colker National Institute of Building Sciences

Roger Grant National Institute of Building Sciences

Henry Green National Institute of Building Sciences

Earle Kennett National Institute of Building Sciences

Get Moy National Institute of Building Sciences

Kent Peterson National Institute of Building Sciences

Paul Torcellini National Renewable Energy Laboratory

Cathy Higgins New Buildings Institute

Carolyn Sarno Northeast Energy Efficiency Partnerships

Peter Turnbull Pacific Gas & Electric (PG&E)

Lawrence Miltenberger PNC Bank Corporation

Scott Williams Target Corporation

Dave Del Rossi TD Bank Corporation

Kristine Kingery U.S. Army

Kristen Thomas U.S. Army

Cody Taylor U.S. Department of Energy 

Sonia Punjabi U.S. Department of Energy

Cindy Jacobs U.S. Environmental Protection Agency