Nanaimo Step Code Requirements

Current Step: 3 | ACH Target: 2.5 ACH50 | Climate Zone: 4 | HDD: ~3,000 | Permit Office: nanaimo.ca/building

Current Requirements

The City of Nanaimo requires Step 3 for all new Part 9 residential buildings in line with the provincial mandate. Active Step Code enforcement has been in place since the province-wide requirement took effect, and the city’s building department has developed a solid process for reviewing energy compliance documentation alongside standard permit applications.

Nanaimo’s construction market has been growing steadily, with significant residential development across the city. This means more builders are going through the Step Code compliance process for the first time, and the local building department is well equipped to support permit applicants through the energy requirements.

Climate Zone 4: A Moderate Path to Compliance

Nanaimo sits in Climate Zone 4 with approximately 3,000 heating degree days. This is slightly higher than Victoria (HDD ~2,600) due to less coastal moderation, but still well within the range where CZ4 compliance is straightforward compared to Interior BC cities. The moderate HDD value means:

Energy models are forgiving: The heating load calculation produces manageable numbers that do not require extreme insulation strategies
Standard wall assemblies work: A well-detailed 2x6 wall with proper air sealing can meet Step 3 requirements without exotic materials or double-stud configurations
Heat pump efficiency stays high: Mid-Island winter temperatures rarely push air-source heat pumps into low-efficiency territory
Less thermal bridging sensitivity: The energy model is less punished by thermal bridging at CZ4 HDDs than at CZ5 or CZ6

Compared to builders working in Kelowna or Kamloops, Nanaimo builders have a real climate advantage. A design that just barely passes Step 3 in the Okanagan will likely pass with margin in Nanaimo.

Air Sealing: The Critical Success Factor

Even with Nanaimo’s moderate climate, air sealing is the key lever for hitting the 2.5 ACH50 target consistently. The most common reasons builders fail their final blower door test are air leakage issues, not insulation shortfalls. Focus areas include:

Sill plate to foundation connections: Gasket or sealant at the sill plate is non-negotiable
Rim joist assemblies: Spray foam or carefully detailed rigid foam with sealed edges
Penetrations: Every pipe, wire, and duct that passes through the air barrier needs individual attention
Window and door rough openings: Backer rod and sealant or tape, not just spray foam
Ceiling plane: Electrical boxes, pot lights, attic hatches, and top-of-wall connections

Our air sealing methods guide covers each of these areas in detail. A pre-drywall air sealing test is the most effective way to verify your envelope before close-in.

Permit Process

Nanaimo follows the standard BC permit framework for Step Code compliance:

Pre-construction: Engage a registered energy advisor to model your design and produce a Section 9B compliance report
Permit application: Submit the energy compliance report with your building permit application to the City of Nanaimo Building Permits department
Mid-construction: Optional pre-drywall blower door test (strongly recommended)
As-built: Final blower door test confirming 2.5 ACH50 and as-built energy compliance report required before occupancy permit is issued

Rebates and Incentives

Nanaimo is served by BC Hydro for electricity and FortisBC for natural gas, giving builders access to both utility rebate streams:

FortisBC: Up to $9,000 at Step 3, $15,000 at Step 4, and $20,000 at Step 5 through the hybrid heat pump pathway (full guide)
BC Hydro New Construction: Incentives for high-performance all-electric homes
CleanBC Better Homes: Provincial and federal incentives that stack with utility programs

Builders targeting Step 4 can access significantly higher rebate tiers. For duplexes and triplexes, the per-unit rebates multiply, making the business case for exceeding the minimum very strong. Use our rebate calculator to run the numbers for your Nanaimo project.

Looking Ahead: Step 4

Step 4 is expected province-wide in 2027. For Nanaimo builders, the biggest change will be the airtightness target dropping from 2.5 to 1.5 ACH50. The insulation requirements at CZ4 are manageable, but achieving 1.5 ACH50 requires a more deliberate air sealing strategy than most builders currently use.

The good news is that Nanaimo’s moderate climate means the envelope upgrades for Step 4 are less expensive here than in Interior or Northern BC. Builders who start practicing now have time to refine their approach before the requirement takes effect.

What Builders Should Do Now

Run a pre-drywall blower door test on your next project to identify where your air leakage issues are before drywall covers them up
Target Step 4 on one project to test your crew’s ability to hit 1.5 ACH50 while rebates reward the effort
Stack your rebates: Combine FortisBC and CleanBC incentives for Step 4 builds to offset the incremental cost
Train your crews on air sealing methods with a focus on the transition details that cause most blower door test failures
Contact the City of Nanaimo Building Permits department early in your design process to confirm current requirements and any local updates