How the NECB 2020 is laid out
The NECB borrows the NBC's three-Division shape but fits it into a single volume. Picture it before you tab it.
Three Divisions in one book
Division A holds Part 1 Compliance, Part 2 Objectives and Part 3 Functional Statements. Division B, the acceptable solutions, runs Part 1 General, Part 2 (Reserved), Part 3 Building Envelope, Part 4 Lighting, Part 5 Heating, Ventilating and Air-conditioning Systems, Part 6 Service Water Systems, Part 7 Electrical Power Systems and Motors, Part 8 Building Energy Performance Compliance Path, Part 9 (Reserved) and Part 10 Tiered Building Energy Performance Compliance. Then comes the climatic information with Table C-1, and after it Division C, the administrative provisions, followed by the index. Parts 2 and 9 of Division B are empty placeholders, so do not go looking for them.
Three ways to comply
Division B Article 1.1.2.1, on page 1-1, gives three routes: the prescriptive or trade-off requirements of Parts 3 to 7, the performance requirements of Part 8, or the tiered requirements of Part 10. The envelope then splits the first route in two under 3.1.1.3, a prescriptive path in Section 3.2 and a trade-off path in Section 3.3, which is where the "four ways to comply" you will hear from colleagues comes from. Only the envelope (3.3) and lighting (4.3) have trade-off sections; the HVAC, service water and electrical trade-off sections are Reserved. Figure A-1.1.2.1, one leaf past the Notes to Part 1 on page 1-9, draws the whole decision as a flow chart.
Notes, folios and the page-number trap
The explanatory notes sit at the end of each Part, not in a separate appendix. The Part 3 notes run from page 3-13 to 3-18, and the Division C Part 2 notes are on page 2-7, almost the last page before the index. Because each Division numbers its pages from 1-1, the same folio can exist two or three times: page 3-1 is the functional statements in Division A and the envelope scope in Division B, and page 2-1 is the objectives in Division A and the construction documents article in Division C. Write "Div A" or "Div C" on any flag that points outside Division B.
Semi-heated buildings live in Part 1
One envelope rule is filed where nobody looks for it. Article 1.2.1.2 on page 1-2 defines a semi-heated building as one with a design set-point below 15°C. Every Part 3 table is then read with degree-days taken at 15°C rather than 18°C, and the trade-off path is not available at all. It sits in Division B Part 1, not in Part 3, which is exactly why it earns a flag.