Primary Reference

NECB 2020, National Energy Code for Buildings for the ExAC

The National Energy Code of Canada for Buildings (NECB) 2020 sets Canada's minimum energy efficiency requirements for new buildings. On Examitect's ExAC study plan, the NECB 2020 is the sole primary reference for Section 2 category 5.25: Apply the principles of the National Energy Code of Canada for Buildings.

Try a free ExAC practice question See plans

NECB overview

NECB at a glance

Full titleNational Energy Code of Canada for Buildings 2020
Edition5th edition (preceded by 2017, 2015, 2011, and the 1997 Model National Energy Code for Buildings)
DeveloperCanadian Commission on Building and Fire Codes (CCBFC). The CCBFC was replaced by the Canadian Board for Harmonized Construction Codes (CBHCC) in November 2022; the CBHCC governs future editions.
PublisherNational Research Council of Canada (NRC)
LanguagesEnglish and French
Primary audienceArchitects, engineers, building officials, and code consultants involved in new building design and additions
Where to accessThrough the National Research Council of Canada (NRC). Check nrc-cnrc.gc.ca for current access terms and pricing.

Why NECB matters for the ExAC

The NECB is the National Energy Code of Canada for Buildings, a model code that sets minimum technical provisions for energy efficiency across the building envelope, lighting, HVAC, service water systems, and electrical power systems. The 2020 edition is the fifth in the series and is the current reference for ExAC preparation. Like the NBC, it has no force of law on its own; it applies only when a province or territory adopts it, with or without amendments.

The NECB appears in one specific place on Examitect's ExAC study plan: Section 2, category 5.25. The category task is direct: "Apply the principles of the National Energy Code of Canada for Buildings (NECB)." The NECB 2020 is the sole primary reference listed for that category. No other ExAC category lists NECB. That tight scope means Section 2 candidates need depth, not breadth, on this code.

To answer NECB questions well, you also need to understand how it relates to the NBC. NBC Part 9 Section 9.36 covers energy efficiency for houses and small buildings and references NECB as one acceptable solution. For larger buildings, NECB governs energy compliance directly. Knowing which code applies to which project is a common Section 2 question pattern.

How to study NECB for the ExAC

  • Start with Division A before opening Division B. Division A Part 2 gives you the single objective (OE, OE1, OE1.1) and Division A Part 3 gives you the functional statements (F90 through F100). Understanding this structure lets you reason through unfamiliar prescriptive requirements rather than memorizing every number in isolation.
  • Memorize the three compliance paths defined in Division B Article 1.1.2.1: prescriptive/trade-off (Parts 3 through 7), performance (Part 8, whole-building energy modelling), and tiered (Part 10, above-baseline performance). ExAC questions regularly ask which path applies in a given scenario.
  • Prioritize Part 3 (Building Envelope) and Part 5 (HVAC). These two Parts carry the most direct overlap with architectural design decisions and the highest concentration of ExAC questions.
  • Learn the key air leakage numbers. Whole-building testing limit: 1.50 L/s/m² at 75 Pa (ASTM E3158). Air barrier assembly compliance: 0.2 L/s/m² at 75 Pa. Component limits vary: curtain walls and fixed windows are 0.2, operable windows and standard doors are 0.5, overhead doors are 2.0.
  • Work through the NBC-NECB relationship on paper. Given a project description (building type, size, location), practise determining whether the project falls under NBC 9.36, NECB, or both. This is a frequent source of scenario questions.
  • Read the BC Energy Step Code Builder Guide and Design Guide. These supplementary references on Examitect's ExAC study plan show how NECB's tiered compliance framework (Part 10) works in practice and clarify the difference between meeting the NECB baseline and meeting a step code tier above it.
  • Remember the Part numbering gap in Division B (jumps from Part 1 to Part 3, with no Part 2 or Part 9). The numbering aligns with the NBC, where Part 9 covers small buildings. Knowing the gap prevents confusion on exam day.

ExAC sections NECB supports

  1. Section 2

    NECB is the sole primary reference for category 5.25 (apply the principles of the National Energy Code of Canada for Buildings). It is the only ExAC category where NECB appears. All other Section 2 categories (5.1 through 5.24) are covered by the NBC 2020 instead.

Inside NECB, the Divisions and Parts

NECB 2020 uses the same three-Division structure as the NBC. Division B numbers Parts to align with NBC equivalents, which leaves a gap (no Part 2 or Part 9 in NECB Division B). Because NECB is published behind a paywall by the National Research Council, the sub-section labels below are shown as tags for orientation, not as links. Here is how the structure maps to ExAC Section 2.

Division or PartWhat it coversWhere it lands on the ExACSub-sections
NECB: Division ACompliance, Objectives, Functional Statements
 The compliance framework. Defines terms, sets the single objective (OE1.1), establishes functional statements F90 through F100, and frames how Division B provisions tie back to limiting excessive energy use. Section 2: 5.25 (apply the principles of the NECB), as the framework that all NECB requirements trace back to.
  • Part 1: Compliance
  • Part 2: Objectives (OE, OE1, OE1.1)
  • Part 3: Functional Statements
  • Definitions of Terms
  • F90–F100 Statements
NECB: Division B, Part 1General & Compliance Paths
 General provisions plus the three compliance paths: prescriptive/trade-off (Parts 3 through 7), performance (Part 8), and tiered (Part 10). Defines which path applies and what each demonstrates. Section 2: 5.25 (path selection and applicability questions).
  • 1.1 General
  • Article 1.1.2.1. Compliance
  • Prescriptive / Trade-off
  • Performance (Part 8)
  • Tiered (Part 10)
NECB: Part 3Building Envelope
 Thermal transmittance limits by climate zone, air barrier system requirements, fenestration and door limits, continuous insulation, and thermal bridging. The most architecturally relevant Part of the code. Section 2: 5.25 (envelope provisions and air leakage limits are the highest-yield NECB territory).
  • 3.1 General
  • 3.2 Building Envelope
  • 3.2.4 Air Leakage
  • Article 3.2.4.2 Whole-Building Test
  • Article 3.2.4.3 Assembly Compliance
  • Thermal Transmittance Limits
  • Fenestration & Doors
NECB: Part 4Lighting Systems
 Connected lighting power density limits by space type, exterior lighting power limits, daylighting controls, occupancy sensing, and time-of-day controls. Section 2: 5.25 (lighting power density and controls questions).
  • 4.1 General
  • 4.2 Lighting Power Density
  • 4.3 Lighting Controls
  • Daylighting & Occupancy
  • Exterior Lighting
NECB: Part 5HVAC Systems
 Equipment efficiency ratings, economizers, heat recovery, duct and pipe insulation, ventilation controls, and zoning. Heavily tested alongside Part 3 in envelope-and-HVAC questions. Section 2: 5.25 (HVAC equipment and controls questions).
  • 5.1 General
  • 5.2 Equipment Efficiency
  • 5.3 HVAC Controls
  • Economizers & Heat Recovery
  • Duct & Pipe Insulation
NECB: Part 6Service Water Systems
 Service water heater efficiency, distribution system insulation, pump controls, and pool heaters. Narrower scope but high-yield for service-water questions. Section 2: 5.25 (service water heating questions).
  • 6.1 General
  • 6.2 Water Heater Efficiency
  • Distribution Insulation
  • Pump & Pool Controls
NECB: Part 7Electrical Power Systems & Motors
 Voltage drop limits, transformer efficiency standards, motor efficiency, and energy monitoring provisions for buildings with electrical service over 250 kVA. Section 2: 5.25 (monitoring provisions and electrical efficiency questions).
  • 7.1 General
  • 7.2 Monitoring (250 kVA)
  • Voltage Drop Limits
  • Transformer & Motor Efficiency
NECB: Part 8Performance Compliance Path
 Whole-building energy modelling. The design building's annual energy use must not exceed that of a reference building meeting the prescriptive limits. Allows trade-offs across Parts. Section 2: 5.25 (energy modelling and performance-path questions).
  • 8.1 General
  • Reference Building
  • Proposed Building Model
  • Annual Energy Use Comparison
NECB: Part 10Tiered Performance Compliance
 A framework for demonstrating energy performance above the NECB baseline. Aligned with provincial step codes (most notably the BC Energy Step Code). Section 2: 5.25 (tiered/step code questions, supplemented by the BC Step Code guides).
  • 10.1 General
  • Tiered Energy Targets
  • Above-Baseline Performance
  • Provincial Step Codes
NECB: Division CAdministrative Provisions
 Rules about how the code is administered and enforced. Adopting jurisdictions frequently customize these provisions. Know it exists and what it covers. Section 2: background context for 5.25 (code scope and administration).
  • Part 1: General
  • Part 2: Administrative Provisions

If you're short on time, Division A (objective and functional statement framework), Division B Part 1 (compliance paths), Part 3 (Building Envelope), and Part 5 (HVAC) carry the heaviest exam load on category 5.25. Parts 4, 6, and 7 are narrower but high-yield for their specific topics. Part 8 (performance path) and Part 10 (tiered) appear less often but are common scenario triggers.

Key NECB terms every ExAC candidate should know

The NECB's Division A definitions and Division B technical terms are precise and deliberately worded. These terms appear in ExAC questions without re-definition, so learning them from the code is faster than guessing from everyday usage.

TermWhat it means in NECBWhere to read in NECB
Energy use efficiency The NECB's stated measure of performance. Every NECB requirement aims to limit excessive energy use (OE1.1), not to maximize absolute efficiency.
  • Division A: Part 2 Objectives
  • OE1.1
Prescriptive path The compliance route where each system component meets the specific numerical limits in Parts 3 through 7. Most straightforward for buildings with standard assemblies.
  • Division B: Article 1.1.2.1.
  • Division B: Parts 3–7
Trade-off A provision within the prescriptive path that allows a below-limit component to be offset by an above-limit component within the same Part. Trade-offs cannot cross Parts.
  • Division B: Article 1.1.2.1.
  • Division B: Parts 3–7
Performance path (Part 8) The whole-building energy modelling compliance route. The design building's annual energy use is compared to a reference building. Allows greater design freedom than the prescriptive path.
  • Division B: Part 8
  • Reference Building
Tiered compliance (Part 10) A framework for demonstrating energy performance above the NECB baseline. Aligns with provincial step codes where higher tiers are required or incentivized.
  • Division B: Part 10
  • BC Energy Step Code (supp.)
Air barrier system A continuous assembly that limits uncontrolled air movement through the building envelope. NECB requires a continuous air barrier in all buildings, with two compliance options: whole-building testing (1.50 L/s/m² at 75 Pa) or air barrier assembly (0.2 L/s/m² at 75 Pa).
  • Division B: Article 3.2.4.1
  • Division B: Article 3.2.4.2
  • Division B: Article 3.2.4.3
Functional statement (F90–F100) Plain-language descriptions in Division A Part 3 of what each Division B provision is intended to achieve. F90 and F92 address air and thermal control in the envelope; F94 through F97 address energy demand for lighting, HVAC, service water, and electrical systems.
  • Division A: Part 3
  • F90–F100 Statements
OE1.1 The sub-objective "limit probability of excessive use of energy." Every single NECB requirement is attributed to OE1.1. Knowing this makes it easier to reason through unfamiliar provisions.
  • Division A: Part 2 Objectives
  • OE → OE1 → OE1.1
CBHCC Canadian Board for Harmonized Construction Codes. The body that governs the harmonized model code suite (including NECB and NBC) as of November 2022. CCBFC developed the NECB; CBHCC now governs the suite.
  • Division A: Preface
  • NRC Code Governance
Thermal transmittance The rate of heat flow through an assembly (expressed as a U-value or RSI). NECB Part 3 sets maximum thermal transmittance limits for walls, roofs, floors, and fenestration by climate zone.
  • Division B: Section 3.2
  • Climate Zone Tables
Design temperature (Table C-1) Climate data in NECB Appendix C specifying January and July dry-bulb and wet-bulb design temperatures, heating degree days, and wind pressures for Canadian locations. Required for HVAC equipment sizing and energy performance calculations.
  • Appendix C: Table C-1
  • Division B: Part 5
Monitoring provision (Part 7) A requirement that buildings with electrical service over 250 kVA include physical provisions (conduit, panel space) for future energy monitoring of HVAC, interior lighting, and exterior lighting. Monitoring equipment itself is not required to be installed.
  • Division B: Part 7
  • Article 7.2.1.1

Tips for Intern Architects reading NECB

Tip 1, Confirm local adoption before applying anything. NECB is a model code. Some provinces adopt it directly, others adopt it with amendments, and some use their own energy codes. British Columbia, for example, layers the BC Energy Step Code on top of NECB. Ontario has incorporated energy requirements differently in the Ontario Building Code. Never assume the federal NECB text applies without checking.

Tip 2, Know the Part numbering gap. Division B jumps from Part 1 to Part 3. There is no Part 2 or Part 9 in NECB Division B. When you're reading an Article reference like "3.2.4.1", the leading digit is the Part number (Part 3: Building Envelope). Getting comfortable with this numbering system saves time when navigating the code on the exam.

Tip 3, Understand that NECB sets minimums only. The code establishes the minimum acceptable performance for each system. Many building projects, especially those targeting green building ratings or meeting step code requirements, go beyond these minimums. On the ExAC, the question is usually about meeting the code floor, not about exceeding it.

Tip 4, Air leakage testing requires design-stage planning. Whole-building air leakage testing under ASTM E3158 must be specified and coordinated before construction begins. You need to detail the air barrier continuity at all penetrations and interfaces, and the test itself must be scheduled before partitions and finishes close in. If you wait until construction, it's too late to fix air barrier gaps easily.

Tip 5, The performance path doesn't mean fewer requirements. Part 8 gives more design flexibility because you can trade off performance across systems (not just within a Part). But it requires a full energy model, a reference building definition, and documentation of the comparison. For a straightforward building, the prescriptive path is often faster. For a building with one high-performing system offsetting another, the performance path may be the only viable route.

Tip 6, Part 7 monitoring is about provisions, not equipment. The code requires buildings over 250 kVA to include provisions to facilitate monitoring of HVAC, interior lighting, and exterior lighting. This means panel space, conduit, and breaker capacity for future metering. It does not require actual monitoring devices or data logging at the time of construction. Architects coordinate this with the electrical consultant during design development.

Tip 7, Use climate data carefully in energy calculations. NECB Appendix C (Table C-1) provides design temperatures and degree days for Canadian locations. The January 2.5% design temperature drives heating system sizing. The July 2.5% dry-bulb and wet-bulb temperatures drive cooling. Degree days below 18 degrees Celsius drive annual energy estimates. Selecting the wrong location or the wrong percentile column affects all downstream calculations.

Common ExAC scenarios where NECB is the answer

  • You are designing a new four-storey office building. The project team wants to use a curtain wall system and needs to confirm the maximum allowable air leakage rate for the assembly. Which NECB Part and Article applies, and what is the limit?
  • The mechanical consultant proposes exceeding the NECB HVAC efficiency requirements to offset a building envelope assembly that is slightly below the thermal transmittance limit. Is this allowed under the prescriptive path? If not, which compliance path should you consider?
  • A client is building a new two-storey, 400 m² house in Alberta. The contractor asks whether the NECB or NBC Section 9.36 governs the energy performance requirements. How do you determine which applies, and what is the relationship between them?
  • A project in British Columbia must meet the BC Energy Step Code Tier 3. Your engineer asks which part of the NECB this refers to and what demonstrating Tier 3 performance requires. What do you tell them?
  • The electrical engineer is sizing the distribution system at 310 kVA. What specific NECB requirement does this trigger, and what must the design include?
  • Your client wants to demonstrate that the building exceeds the NECB minimum through energy modelling rather than prescriptive compliance. What compliance path does this involve, and what is the key requirement it must satisfy?
  • During design development, a peer reviewer notes that your air barrier detail at a major thermal bridge may not satisfy NECB requirements. Which functional statement(s) and prescriptive articles should you review to resolve the issue?

How NECB compares to other ExAC references

NECB is the sole primary reference for Section 2 category 5.25, but it sits alongside the other primary ExAC references that candidates read for different purposes. Use this comparison to keep the references straight.

ReferenceWhat it's forHow NECB relates
NECBMinimum energy efficiency requirements for new buildings and additions, covering envelope, lighting, HVAC, service water systems, and electrical power systems.The sole primary reference for Section 2 category 5.25 on Examitect's ExAC study plan.
NBC 2020Minimum building requirements: occupancy, fire safety, structure, accessibility, and envelope, for buildings across Canada.The companion code in Section 2. NBC covers categories 5.1 through 5.24; NECB covers category 5.25. For Part 9 (small) buildings, NBC Section 9.36 references NECB as an acceptable solution for energy compliance.
CHOPArchitectural practice management, including code research workflow and the AHJ relationship.Different jobs. NECB carries the energy provisions you must comply with; CHOP describes how to manage the broader compliance and practice process. CHOP is primary for Sections 1, 3, and 4; NECB is primary only for Section 2 category 5.25.
CHINGBuilding assemblies, construction systems, and detailing.CHING illustrates how envelope assemblies are built; NECB sets the minimum energy performance those assemblies must meet. Many assemblies CHING shows are designed to achieve common NECB thermal transmittance and air leakage values.
Provincial energy codesThe law in each province or territory, adopted from the model NECB with local amendments (or replaced entirely, as in Ontario and BC).The ExAC tests the model NECB 2020, not any province's adopted version. Be aware that amendments and step codes exist and govern real projects, but study the model for the exam.
RSMeans and YardsticksConstruction cost data for early-stage estimating.NECB requirements influence cost by setting minimum standards for envelope, lighting, and mechanical systems. The cost references give you the numbers to estimate those compliance costs in Section 1.

How Examitect reinforces NECB

Examitect's Section 2 practice questions include scenario-based problems built around NECB 2020. You'll work through compliance path selection, air leakage limit application, the NBC-NECB relationship for Part 9 buildings, and Division A objective attribution. These questions are designed so you can't just recognize the answer: you have to apply the code logic to a specific project situation.

Reading NECB once will help you navigate it. Practising with questions that force you to apply it is what builds the retrieval speed you need on exam day. See the full question bank at Examitect's free trial and the plans page for full Section 2 coverage.

FAQ

NECB FAQ

The National Energy Code of Canada for Buildings (NECB) is a model code that sets minimum technical requirements for energy efficiency in new buildings and additions. It is developed by the Canadian Commission on Building and Fire Codes (CCBFC) and governed by the Canadian Board for Harmonized Construction Codes (CBHCC) as of 2022. It has no force of law until a provincial or territorial government adopts it.

Yes. NECB 2020 is listed as the sole primary reference for category 5.25 in Section 2 on Examitect's ExAC study plan. The category task is: "Apply the principles of the National Energy Code of Canada for Buildings (NECB)." This is the only ExAC category where NECB appears as a primary reference.

NECB 2020 offers three compliance paths defined in Division B Article 1.1.2.1: the prescriptive/trade-off path (each system component meets numerical limits in Parts 3 through 7, with trade-offs allowed within a Part), the performance path (Part 8, whole-building energy modelling against a reference building), and the tiered performance path (Part 10, demonstrating above-baseline performance for jurisdictions with step codes).

Under NECB 2020 Article 3.2.4.2, the maximum whole-building air leakage rate is 1.50 L/s/m² at 75 Pa pressure differential, tested to ASTM E3158. The alternative air barrier assembly path (Article 3.2.4.3) requires a maximum of 0.2 L/s/m² at 75 Pa. Individual components such as curtain walls and fixed windows also have a limit of 0.2 L/s/m², while operable windows and standard doors are limited to 0.5 L/s/m².

The National Building Code of Canada (NBC) covers fire safety, life safety, structural requirements, accessibility, and building envelope performance broadly. The NECB is focused exclusively on energy efficiency. For Part 9 buildings (houses and small buildings), NBC Section 9.36 addresses energy efficiency and references NECB as an acceptable solution. For larger buildings, the NECB typically governs energy directly.

NECB has one principal objective: OE (Environment). Under OE is sub-objective OE1 (Resources), and under OE1 is OE1.1, which addresses excessive energy use. Every requirement in the NECB traces back to OE1.1. This structure is found in Division A Part 2 and is tested as part of understanding how objective-based codes work.

NECB Part 7 (Article 7.2.1.1) requires buildings with electrical service over 250 kVA to include provisions to facilitate monitoring of HVAC, interior lighting, and exterior lighting. This means the design must accommodate future monitoring hardware: panel capacity, conduit, and breaker space for meters. It does not require that monitoring equipment itself be installed at the time of construction.

Examitect's ExAC study plan lists the NECB 2020 as the primary reference for category 5.25. The 2020 edition is the fifth in the series and is the current version in active use across Canadian jurisdictions. Some provinces may still use earlier editions depending on their local adoption schedule, but the 2020 edition is the reference for ExAC preparation.

Keep exploring

Other ExAC reference books.

NECB covers energy. These are the other primary references on Examitect's ExAC study plan.

NBC 2020

National Building Code of Canada. The companion safety code for fire, life safety, structure, accessibility, and envelope performance.

CHOP

Canadian Handbook of Practice. Primary reference for Sections 1, 3, and 4: practice, contracts, construction administration, and project management.

CHING

Building Construction Illustrated. Graphic reference for construction principles, site design, and assemblies across Sections 1, 2, and 3.

RSMeans

Construction cost data. Used for elemental estimating and cost-management questions in Section 1.

Yardsticks

Hanscomb Yardsticks for Costing. Canadian elemental cost data by building type and region, used alongside RSMeans in Section 1.

Supporting references

The extended reading list of supplementary references that appear across Examitect's ExAC study plan.