The NECB 2020 gives a building three ways to comply: the prescriptive or trade-off requirements of Parts 3 to 7, the whole-building performance path of Part 8, or the tiered performance path of Part 10. Most ExAC questions on objective 5.5 hinge on spotting which route the scenario uses. In our experience, candidates who can read that cue answer faster and avoid the classic distractors. This guide from Examitect, an independent ExAC prep platform unaffiliated with the CACB, walks each path, the reference building, the tiers and the numbers worth finding fast.
| Exam section | Section 2, about 75 multiple-choice questions in three hours, open book |
|---|---|
| Specific objectives | 5.5.1 design process, 5.5.2 construction documents |
| Core article | Division B, Article 1.1.2.1. |
| Trade-off sections | 3.3. envelope and 4.3. interior lighting only |
| Model-based paths | Part 8 performance and Part 10 tiers |
The National Energy Code of Canada for Buildings 2020 shares the NBC's objective-based frame. Article 1.2.1.1. of Division A allows compliance through the acceptable solutions in Division B or through alternative solutions, the same split our post on NBC alternative solutions explains. Everything in this guide sits on the acceptable-solution side.
Inside Division B, Article 1.1.2.1. says buildings shall comply with:
Note A-1.1.2.1. draws the decision as a flow chart, Figure A-1.1.2.1. On the first route you pick a path Part by Part, so a design can meet Part 3 by trade-off and Parts 4 to 7 prescriptively. When a Part fails, the chart sends you to redesign or to another path.
| Path | Where | What you prove | Energy model? |
|---|---|---|---|
| Prescriptive | Sections 3.2., 4.2., 5.2., 6.2., 7.2. | Each listed limit is met | No |
| Trade-off | Sections 3.3. and 4.3. | The envelope or interior lighting uses no more energy than a compliant one | Envelope: no, a UA sum. Lighting: an annual energy calculation |
| Performance | Part 8 | Annual energy consumption is not above the reference building's target | Yes, two models |
| Tiered performance | Part 10 | The Part 8 result lands in Tier 1, 2, 3 or 4 | Yes, the Part 8 models |
Which buildings? Article 1.1.1.1. of Division A applies the NECB to new buildings described in Sentence 1.3.3.2.(1) of Division A of the NBC, the Part 3 buildings, and to additions, but not to farm buildings. Part 9 buildings follow NBC Section 9.36., and Sentence 9.36.1.3.(5) sends those with more than 300 m2 of non-residential occupancies, or with medium-hazard industrial occupancies, to the NECB. Our Part 3 versus Part 9 post covers that boundary.
The prescriptive path is the default. Note A-1.1.2.1. describes it as minimum thermal characteristics and efficiency measures "stated as specific instructions". Each of Parts 3 to 7 holds one, always in Section x.2.:
| Part | Prescriptive section | What it fixes |
|---|---|---|
| Part 3 Building Envelope | 3.2. | FDWR and skylight limits (3.2.1.4.), vestibules (3.2.2.1.), U-value tables by climate zone, air leakage (3.2.4.) |
| Part 4 Lighting | 4.2. | Interior lighting power by the building area method (4.2.1.5.) or the space-by-space method (4.2.1.6.), plus controls |
| Part 5 HVAC Systems | 5.2. | System and equipment requirements, including equipment efficiencies in Article 5.2.12.1. |
| Part 6 Service Water Systems | 6.2. | Service water heating equipment and controls (Table 6.2.2.1.) |
| Part 7 Electrical Power Systems and Motors | 7.2. | Electrical systems and motors, such as motor efficiency to CSA C390 |
For an architect, Part 3 is the Part that matters. Article 3.1.1.2. applies it to the envelope of conditioned buildings whose heating or cooling output is at least 10 W/m2 of floor area, and Article 3.1.1.3. gives the envelope its own three options: the prescriptive path in Section 3.2., the trade-off path in Section 3.3. and the performance path in Section 3.4.
Every prescriptive envelope number keys off heating degree-days. Article 1.1.4.1. takes climatic values from the authority having jurisdiction or, failing that, from Table C-1 for the nearest location. The Part 3 tables then group HDD into Zones 4 to 8. One trap sits in Part 1: Sentence 1.2.1.2.(2) defines a semi-heated building as one with a design set-point below 15°C, and its tables are read with degree-days below 15°C instead of 18°C.
The prescriptive path also anchors the other routes. The reference envelope in a trade-off and the reference building in Part 8 are both built to Sections 3.2. to 7.2., so learn these limits once and you have learned the baseline for every route.
Note A-1.1.2.1. calls the trade-off "an easy way to make small adjustments" without following the whole-building performance route. In the NECB 2020 it exists in two places only. Sections 5.3., 6.3. and 7.3. are printed as Reserved, so HVAC, service water and electrical systems have no trade-off.
Section 3.3. contains a single Subsection, 3.3.1. Simple Trade-off Path. If a study guide mentions a "detailed" envelope trade-off, it is not in the 2020 edition, so an option built on one is a distractor. Article 3.3.1.1. sets the scope and limits:
Article 3.3.1.2. is the test. The proposed and reference buildings have the same total above-ground area, and the sum of each assembly's U-value times its area in the proposed building must not exceed the same sum with every assembly complying with Section 3.2.
Here is our own worked example. A Winnipeg office has 1,000 m2 of gross wall. Table C-1 gives Winnipeg 5670 degree-days below 18°C, Zone 7A, so the maximum FDWR is (2000 − 0.2 × 5670) / 3000, about 0.29. The client wants 0.40, which fails Article 3.2.1.4. Ignoring doors, the reference wall holds 290 m2 of glazing at 1.73 W/(m2·K) and 710 m2 of opaque wall at 0.215, for a UA of about 654 W/K. Keep the proposed 600 m2 of wall at 0.215 (129 W/K) and the 400 m2 of glazing must average about 1.31 W/(m2·K) or better. Better walls would loosen that target; better airtightness would not.
Article 4.3.1.3. compares annual interior lighting energy, not installed power. The proposed building, calculated under Subsection 4.3.2. or CSA C873.4, must use no more than the reference building's allowance under Subsection 4.3.3. or the same standard. Article 4.3.1.2. keeps Articles 4.2.1.1. and 4.2.1.2. in force, along with Subsections 4.2.3. and 4.2.4., so exterior lighting stays prescriptive.
Part 8 replaces the prescriptive requirements of Sections 3.2. to 7.2. or the trade-offs of Sections 3.3. and 4.3., Article 8.1.1.1. Note A-1.1.2.1. describes the proof as two energy analyses: one of the building as if it met the prescriptive requirements, which sets the target, and one of the actual design.
Article 8.1.1.2. applies Part 8 only where the occupancy is known and enough is known about the components. Where information is missing, the prescriptive requirements apply. A design altered during construction must be reassessed, and the method covers one building at a time, though a structure divided by firewalls may be treated as one.
Under Article 8.4.4.1., the reference building's components and systems meet the prescriptive requirements of Sections 3.2. to 7.2. Its floor area, use of spaces, thermal blocks, shape, exterior dimensions and orientation are identical to the proposed building's, and it uses the same climatic data. Sentence 8.4.4.3.(3) is the envelope rule examiners like: if the proposed FDWR differs from the maximum in Article 3.2.1.4., the reference FDWR is adjusted proportionally on each orientation until it complies. Sentence 8.4.4.3.(4) leaves permanent shading devices out of the reference building, while Sentence 8.4.3.1.(8) puts them in the proposed model, which is how fins and overhangs earn credit.
Article 8.4.2.2. requires the model to cover heating, cooling, fans, lighting, service water heating, pumps, auxiliary HVAC equipment, receptacle loads, appliances, and elevators and escalators, over 8 760 hours at intervals of one hour or less. Software must conform to ANSI/ASHRAE 140 or an equivalent test method.
Each Part's x.4. Section points to Part 8 and lists limits that survive it. Article 3.4.1.2. keeps Article 3.2.1.1. and Subsection 3.2.4., protection of insulation and air leakage, in force. Articles 5.4.1.2. and 6.4.1.2. still require HVAC and service water heating equipment to meet the applicable energy efficiency act or standard. For objective 5.5.2, Article 2.2.2.8. of Division C requires a building performance compliance calculation report with envelope, lighting and HVAC data for both the proposed and reference buildings.
Part 10 is new ground for many candidates. Article 10.1.1.1. lets it replace the prescriptive or trade-off provisions, and Article 10.1.1.2. repeats Part 8's application rules. Under Article 10.1.2.1., a building complies by meeting one of four tiers in Table 10.1.2.1., measured with the Part 8 models:
| Energy Performance Tier | Percent building energy target | Percent improvement |
|---|---|---|
| Tier 1 | ≤ 100% | ≥ 0% |
| Tier 2 | ≤ 75% | ≥ 25% |
| Tier 3 | ≤ 50% | ≥ 50% |
| Tier 4 | ≤ 40% | ≥ 60% |
Sentence 10.1.2.1.(2) gives the arithmetic: divide the proposed annual energy consumption by the reference target, or subtract it from the target and divide by the target. Note A-10.1.2.1.(2) works it through. With a 200 GJ target and a 150 GJ design, the result is 75%, or a 25% improvement: Tier 2. At 160 GJ the design reaches only 80%, a 20% improvement, so it is Tier 1.
Tier 1 is the Part 8 pass mark and each higher tier asks for a deeper cut. The model code does not say which tier a project must reach; Article 2.2.1.1. of Division C leaves administration to federal, provincial or territorial regulations or municipal bylaws. BC's version is covered in our BC Energy Step Code post. For the ExAC, answer from the national text.
Objective 5.5 is short on the page of Appendix 1 of the 2026 Preparation Guide (p.17): 5.5.1 applies the NECB to the design process and 5.5.2 to the construction documents. Both verbs are "apply", so expect a scenario, and the scenario usually tells you the path in a few words:
| Cue in the question | Path | Open |
|---|---|---|
| Maximum U-value, FDWR limit, climate zone, vestibule | Prescriptive | Section 3.2., Table C-1 |
| More glazing offset by better walls or windows, UA | Simple trade-off | Articles 3.3.1.1. and 3.3.1.2. |
| Lighting energy compared with an allowance | Lighting trade-off | Section 4.3. |
| Energy model, reference building, unmet hours | Performance | Part 8, Article 8.4.1.2. |
| Percent better than the reference, a named tier | Tiered performance | Table 10.1.2.1. |
| What the drawings or report must show | Documentation | Division C, Subsection 2.2.2. |
Sentence 3.2.1.4.(1) sets the maximum FDWR at 0.40 up to 4000 HDD, (2000 − 0.2 × HDD) / 3000 between 4000 and 7000, and 0.20 at 7000 or more. Table A-3.2.1.4.(1) prints the results, and skylights stay under 2% of the gross roof area. The zone bands and the Zone 4 to Zone 8 limits from Tables 3.2.2.2. and 3.2.2.3.:
| Zone (HDD below 18°C) | Walls, W/(m2·K) | Vertical fenestration | Example from Table C-1 |
|---|---|---|---|
| 4 (under 3000) | 0.290 | 1.90 | Vancouver (City Hall) 2825 |
| 5 (3000 to 3999) | 0.265 | 1.90 | Toronto (City Hall) 3520, FDWR 0.40 |
| 6 (4000 to 4999) | 0.240 | 1.73 | Montréal (City Hall) 4200, FDWR about 0.39 |
| 7A (5000 to 5999) | 0.215 | 1.73 | Winnipeg 5670, FDWR about 0.29 |
| 7B (6000 to 6999) | 0.190 | 1.44 | Whitehorse 6580, FDWR about 0.23 |
| 8 (7000 and over) | 0.165 | 1.44 | Yellowknife 8170, FDWR 0.20 |
Section 2 is the only open-book section. The 2026 Preparation Guide (p.12) permits paper copies of the NECB 2020 with annotations, highlighting and tabs made beforehand, but no added pages and no marks in the room. Our guide on how to tab the NECB 2020 covers the flags; this sequence is how to use them:
Match the stem's wording to prescriptive, trade-off, performance, tiered or documentation.
Take HDD below 18°C from Table C-1, or below 15°C for a semi-heated building, and note the zone.
Confirm the path is open: no simple trade-off for additions or semi-heated buildings, and Part 8 or Part 10 only when occupancy and components are known.
Read the prescriptive limit in Section 3.2., the FDWR from Sentence 3.2.1.4.(1) or the reference building rules in Subsection 8.4.4.
Compare the limit, the UA sum, the energy target or the tier percentage, whichever the path requires.
Rule out options that ignore Article 3.4.1.2., the equipment efficiency limits or the Division C documentation.
These items are lookups once the path is clear, so bank them; our Section 2 pacing post explains why. The NECB 2020 reference guide covers the rest of the code.
Article 1.1.2.1. of Division B of the NECB 2020 lists three: the prescriptive or trade-off requirements of Parts 3 to 7, the performance requirements of Part 8, and the tiered performance requirements of Part 10. The prescriptive and trade-off options are chosen Part by Part.
No, the NECB 2020 has no detailed trade-off path. Section 3.3. of Division B contains only Subsection 3.3.1., the Simple Trade-off Path for the building envelope. The only other trade-off is the interior lighting trade-off in Section 4.3.
Only Part 3, Building Envelope, in Section 3.3., and Part 4, Lighting, in Section 4.3., have a trade-off path in the NECB 2020. Sections 5.3., 6.3. and 7.3. for HVAC, service water and electrical systems are Reserved.
The reference building is a model of the same building built to the prescriptive requirements of Sections 3.2. to 7.2. Under Article 8.4.4.1., it has the same floor area, space use, thermal blocks, shape, dimensions, orientation and climatic data as the proposed building. Its annual energy consumption is the building energy target.
No, the NECB performance path does not remove every prescriptive envelope rule. Article 3.4.1.2. keeps Article 3.2.1.1., protection of insulation materials, and Subsection 3.2.4., air leakage, in force even when Part 8 is used.
Sentence 3.2.1.4.(1) of the NECB 2020 sets the maximum FDWR at 0.40 up to 4000 heating degree-days, (2000 − 0.2 × HDD) / 3000 between 4000 and 7000, and 0.20 at 7000 or more. Table A-3.2.1.4.(1) lists the results in 250 HDD steps.
Table 10.1.2.1. of the NECB 2020 sets four tiers. Tier 1 is at or below 100% of the reference building's energy target, Tier 2 at or below 75%, Tier 3 at or below 50% and Tier 4 at or below 40%, which equals 0%, 25%, 50% and 60% improvement.
Yes, the 2026 ExAC Preparation Guide permits a paper copy of the NECB 2020 during Section 2 only. It may carry annotations, highlighting and tabs made beforehand, but added pages are not allowed, nor is marking the book in the room.