NECB

A short overview of the National Energy Code of Canada for Buildings and why it matters for the ExAC.

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NECB at a glance

Full title National Energy Code of Canada for Buildings 2020
Edition 5th edition (preceded by the 2017 edition)
Developed by Canadian Commission on Building and Fire Codes (CCBFC)
Governed by Canadian Board for Harmonized Construction Codes (CBHCC), as of 2022
Languages English and French
Primary audience Architects, engineers, building officials, and code consultants involved in new building design
ExAC relevance Sole primary resource for category 5.25 in Section 2 of Examitect's ExAC study plan
Force of law Model code only. Applies when adopted (with or without modifications) by a provincial or territorial government.

Why NECB matters for the ExAC

The NECB appears in one specific location on Examitect's ExAC study plan: Section 2, category 5.25. The task is direct: "Apply the principles of the National Energy Code of Canada for Buildings (NECB)." The NECB 2020 is the sole primary resource listed for this category, which signals that the ExAC tests functional application of the code, not only recall of its structure.

Section 2 covers codes broadly: NBC fundamentals, building classification, fire safety, accessibility, envelope performance, and energy. The NECB is the energy-specific piece. To do well on the NECB questions, you need to understand how the NECB relates to the National Building Code of Canada (NBC). NBC Section 9.36 addresses energy efficiency for Part 9 buildings (houses and small buildings) using a scope similar to NECB but without lighting and electrical power systems. Critically, NECB is referenced as an acceptable solution within NBC Section 9.36, meaning that a designer can use NECB to satisfy the energy requirements of NBC 9.36 on a Part 9 project.

The supplementary resources listed on Examitect's ExAC study plan for category 5.25 are the BC Energy Step Code Builder Guide and BC Energy Step Code Design Guide. These illustrate how one jurisdiction layers tiered energy performance requirements on top of the NECB baseline, giving you practical context for NECB's tiered compliance path in Part 10.

ExAC sections NECB supports

Section 2

What NECB is

The National Energy Code of Canada for Buildings (NECB) 2020 is Canada's primary model code for energy efficiency in new buildings and additions. It sets minimum technical provisions for energy performance across the building envelope, lighting, HVAC, service water heating, and electrical power systems. The 2020 edition is the fifth in the series, following the 2017 release.

The NECB is a model code, which means it has no force of law on its own. It applies only when a provincial or territorial government adopts it, with or without modifications. Adoption and amendments vary across Canada, so you always need to confirm which edition is in force for the jurisdiction you're working in before applying any specific provision.

One key fact: the NECB is regulation, not a design guideline. It establishes minimum acceptable performance levels only. Good energy-efficient design typically goes beyond these minimums, but the NECB defines the floor, not the ceiling.

Inside NECB: Divisions and Parts

NECB 2020 uses the same three-Division structure as the NBC. Here is the full breakdown you need for the ExAC:

Division / Part Content
Division A Compliance, Objectives, and Functional Statements
Division A, Part 2 Objectives: single principal objective OE (Environment); sub-objective OE1 (Resources); OE1.1 (Excessive Use of Energy)
Division A, Part 3 Functional Statements F90 through F100, covering air leakage, thermal transfer, lighting energy, heating and cooling energy, service water heating, and electrical equipment
Division B Acceptable Solutions (all technical requirements)
Division B, Part 1 General provisions; three compliance path options
Division B, Part 3 Building Envelope: thermal transmittance limits by climate zone, air barrier system requirements, fenestration limits
Division B, Part 4 Lighting Systems: connected lighting power density limits, daylighting controls, occupancy sensing
Division B, Part 5 HVAC Systems: equipment efficiency ratings, economizers, heat recovery, controls
Division B, Part 6 Service Water Systems: water heater efficiency, distribution system insulation
Division B, Part 7 Electrical Power Systems and Motors: voltage drop limits, transformer standards, motor efficiency, energy monitoring provisions
Division B, Part 8 Building Energy Performance Compliance Path (performance/modelling path)
Division B, Part 10 Tiered Building Energy Performance Compliance (above-baseline tiers)
Division C Administrative Provisions

Note the Part numbering gap: Division B goes from Part 1 directly to Part 3. There is no Part 2 or Part 9 in NECB Division B. Part numbers were chosen to align with the NBC structure, where Part 9 covers small buildings. Remembering this gap prevents confusion when you're navigating the code on the exam.

The three compliance paths are defined in Division B Article 1.1.2.1:

  • Prescriptive/trade-off path: Each system meets numerical limits in Parts 3 through 7. Within a given Part, a component performing below the limit can be offset (traded off) by another component performing above it.
  • Performance path (Part 8): Whole-building energy modelling. The building's predicted annual energy use cannot exceed that of a reference building meeting the prescriptive limits.
  • Tiered performance path (Part 10): Demonstrates performance above the NECB minimum. Used in jurisdictions such as British Columbia that have adopted energy step codes layered above the NECB baseline.

Key NECB terms every ExAC candidate should know

Term What it means
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.
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.
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.
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.
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.
Air barrier system A continuous assembly that limits uncontrolled air movement through the building envelope. NECB requires a continuous air barrier system in all buildings (Article 3.2.4.1), 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).
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. Used when developing alternative solutions.
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.
CBHCC Canadian Board for Harmonized Construction Codes. The body that governs the harmonized model code suite (including NECB and NBC) as of 2022. Note: CCBFC (Canadian Commission on Building and Fire Codes) developed the NECB; CBHCC governs the suite. They have different roles.
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.
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.
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.

How NECB compares to other ExAC references

Reference Relationship to NECB
NBC 2020 The companion safety code. NBC covers fire, life safety, structure, accessibility, and envelope performance broadly. NECB handles energy efficiency exclusively. For Part 9 buildings, NBC Section 9.36 references NECB as an acceptable solution for energy compliance. You will use both codes on most projects.
CHING No code content. CHING (Building Construction Illustrated) is a graphic reference for construction principles, assemblies, and site design. It supports Section 1, 2, and 3 categories but does not cover regulatory requirements.
CHOP No overlap. The Canadian Handbook of Practice (CHOP) covers architectural practice, contracts, and project management. It is a primary resource for Sections 1, 3, and 4. NECB is the primary resource only for Section 2 category 5.25.
RSMeans No overlap. RSMeans is a construction cost reference. It is a primary resource for Section 1 cost management categories. There is no interaction with energy codes.
Yardsticks No overlap. Yardsticks for Costing is a Canadian elemental cost reference. It is a primary resource for Section 1 cost management categories, not code compliance.

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-F100). Understanding this structure lets you reason through unfamiliar prescriptive requirements rather than memorizing every number in isolation.
  • Memorize the three compliance paths. ExAC questions regularly ask which path applies in a given scenario or what each path requires the designer to demonstrate. Know: prescriptive/trade-off (Parts 3-7), performance (Part 8), and tiered (Part 10).
  • Prioritize Part 3 (Building Envelope) and Part 5 (HVAC). These two parts cover air leakage, thermal transmittance limits, and mechanical equipment efficiency. They have the most direct overlap with architectural design decisions and are the most likely territory for 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 are 0.5, 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 guides. These supplementary resources on Examitect's ExAC study plan show how NECB's tiered compliance framework (Part 10) works in practice. They also clarify the difference between meeting the NECB baseline and meeting a step code tier above it.

ExAC sections NECB supports

ExAC Section How NECB appears on Examitect's ExAC study plan
Section 1: Design and analysis Not listed as a primary or supplementary resource. Energy performance is not the focus of Section 1 design categories.
Section 2: Codes Primary resource for category 5.25: Apply the principles of the National Energy Code of Canada for Buildings (NECB). This is the only ExAC category where NECB is explicitly listed. The BC Energy Step Code guides appear as supplementary resources for the same category.
Section 3: Sustainability and final project Not listed directly. The BC Energy Step Code guides appear as supplementary resources for category 13.1 (climate change impacts on design), and building science topics in categories 8.2 and 8.3 overlap with envelope energy performance. NECB informs that work but is not named as a resource for Section 3 categories.
Section 4: Construction and practice Not listed. Section 4 focuses on contracts, construction administration, and project management.

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 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.

NECB and ExAC 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 resource 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 resource.

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 resource 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 resource 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.