BC Energy Step Code 5: Net-Zero Ready
Key takeaway: Step 5 is Passive-House-adjacent. Airtightness target: 1.0 ACH50. Walls R-30 to R-40 effective, triple-pane U-0.8 windows, 80%+ HRV, all-electric or hybrid heat pump mechanical. Cost premium 8 to 15%. FortisBC rebate up to $20,000 per unit. Energy bills 50 to 70% below code minimum.
What Step 5 actually requires
Step 5 is the highest tier of the BC Energy Step Code for Part 9 residential buildings. It sits one step above the Step 4 target expected provincially in 2027, and effectively brings BC builders to net-zero-ready performance, the same envelope quality target as a Passive House (Passive House requires 0.6 ACH50; Step 5 requires 1.0 ACH50).
| Metric | Step 5 target | Step 4 target | Step 3 target |
|---|---|---|---|
| Airtightness | ≤ 1.0 ACH50 | ≤ 1.5 ACH50 | ≤ 2.5 ACH50 |
| MEUI | ≤ 25 kWh/m²/yr | ≤ 30 kWh/m²/yr | ≤ 50 kWh/m²/yr |
| TEDI | ≤ 15 kWh/m²/yr | ≤ 20 kWh/m²/yr | ≤ 30 kWh/m²/yr |
The compounding effect of these three targets is what makes Step 5 demanding. You can’t paper over a leaky envelope with a better heat pump; TEDI forces envelope-first design.
Wall and roof assemblies for 1.0 ACH50
For Climate Zone 5 (Kelowna, Vernon, Kamloops, Penticton):
| Component | Step 5 spec |
|---|---|
| Wall (effective R-value) | R-30 to R-40 |
| Wall construction | Double-stud (2x4 + 2x4 + insulated cavity) OR 2x6 + R-15+ exterior |
| Vapor strategy | Smart vapor retarder (variable permeance) on interior side |
| Air barrier | Continuous, taped sheathing + membrane belt-and-suspenders |
| Roof / attic | R-60 to R-80 effective, blown cellulose typical |
| Foundation slab | R-15 to R-20 under-slab |
| Foundation walls | R-25+ insulated basement walls or insulated frost-protected shallow foundation |
| Slab edge | R-15 minimum, often more |
Most Step 5 builds use double-stud wall construction (often called “Larsen truss” or “REMOTE wall” depending on detailing). Thermal bridging through framing is minimized to less than 5% of the wall area. See the wall assemblies guide for cold-climate Step 5 build-ups.
Windows that pass Step 5
The window spec is roughly twice the performance of Step 3:
- U-value: 0.8 W/m²K or better (almost always triple-pane)
- Glazing fill: Argon or krypton (krypton for narrower IGUs)
- Spacer: Warm-edge insulating spacer, no metal-only spacers
- Frame: Fiberglass or wood-clad with thermal breaks; some PVC suitable
- Installation: Inset (in-plane with exterior insulation) for thermal continuity
Triple-pane windows in BC retail at $80 to $150/sq ft installed, versus $40 to $70 for Step 3 double-pane low-E. On a typical 2,500 sq ft home with 350 sq ft of glazing, that’s a $14,000 to $28,000 line-item difference.
Mechanical: low load, electric-leaning
Step 5 envelopes have such low heating demand that mechanical sizing changes character.
- Heat pump: Air-source heat pump (ASHP) sized at half to one-third of code-minimum equivalent; cold-climate ASHP rated to -25°C standard
- Domestic hot water: Heat pump water heater (HPWH), often the single biggest electric load
- Ventilation: HRV with 80%+ sensible recovery efficiency, or ERV in coastal/humid climates
- Combustion: Most Step 5 builds skip combustion appliances entirely. EL-4 carbon performance is essentially baked in
- Cooktop: Induction is the standard play
The mechanical room often shrinks 30 to 50% versus a code-minimum build. See HVAC for Step Code for sizing approaches and equipment selection.
Air sealing approach: belt-and-suspenders required
Hitting 1.0 ACH50 reliably requires more than careful manual sealing. The successful Step 5 approach combines:
- Continuous primary air barrier. Self-adhered or fluid-applied membrane on the exterior sheathing, fully detailed at all penetrations
- Sheathing as backup air barrier. Taped seams at every panel
- Interior smart vapor retarder. Doubles as a redundant air barrier
- Aerosol sealing for distributed micro-leaks. The pragmatic path to closing the last 0.5 to 1.0 ACH50; manual sealing alone struggles to land below 1.5 reliably
- Pre-drywall blower door test (mandatory in practice). Pre-drywall testing at 1.5 ACH50 or below is the typical milestone before drywall
Builders attempting 1.0 ACH50 with manual sealing alone typically miss on the first test and rework into the 1.5 to 2.0 range. The cost of that rework usually exceeds the cost of aerosol sealing in the first place.
Cost premium: 8 to 15%
For a typical 2,500 sq ft Step 5 build in CZ5:
| Item | Incremental cost vs Step 3 |
|---|---|
| Triple-pane windows | $12,000 to $25,000 |
| Double-stud wall framing + extra insulation | $20,000 to $40,000 |
| R-60+ ceiling insulation | $3,000 to $6,000 |
| R-15 to R-20 under-slab insulation | $4,000 to $8,000 |
| Aerosol air sealing | $3,000 to $6,000 |
| 80%+ HRV vs basic HRV | $1,500 to $3,500 |
| Heat pump (cold-climate) vs furnace | $5,000 to $12,000 |
| Heat pump water heater vs gas tank | $1,500 to $3,500 |
| Energy advisor (extended scope) | $2,000 to $4,000 |
| Total incremental cost | $52,000 to $108,000 |
That’s 8% to 15% on a $700K to $1.2M build. See cost of compliance for the full breakdown.
Rebate stack for Step 5
| Source | Amount | Notes |
|---|---|---|
| FortisBC New Home Program | $11,000 to $20,000 | Step 5 hybrid heat pump pathway |
| CleanBC Better Homes | $4,000 to $10,000 | Heat pump rebate, stacks |
| BC Hydro New Construction | up to $15,000 | All-electric high-performance homes |
| Greener Homes Loan | up to $40,000 | Interest-free for energy upgrades |
Combined rebate potential on a single Step 5 home: $30,000 to $45,000 in straight rebates plus the Greener Homes loan. That offsets roughly 40 to 60% of the Step 5 premium. See the Step Code rebates guide for stacking rules and current eligibility.
Operating cost and value
Step 5 homes typically use 50 to 70% less energy than code-minimum builds. For a 2,500 sq ft home in CZ5:
- Annual heating bill at code minimum: ~$1,800 to $2,400
- Annual heating bill at Step 5: ~$500 to $900
- Annual savings: ~$1,000 to $1,800
Beyond utility savings, Step 5 homes typically command a 3 to 6% resale premium and qualify for green mortgage products. Comfort gains (no drafts, even temperatures, quiet) are real but harder to quantify in dollars.
Where Step 5 makes sense
Step 5 is overkill for most BC builders today. It makes sense for:
- Custom homes where the buyer is already paying $1,500+/sq ft and values comfort/efficiency
- Acreage and off-grid sites where mechanical complexity is expensive to service
- High-fuel-cost regions where operating savings compound (Yukon-adjacent, propane-served)
- Builders positioning for Step 5 becoming mandatory (currently expected post-2032)
For most builders, Step 4 is the practical 2027 target and Step 5 is an opt-in upgrade for specific projects.
Next steps
- Run the rebate calculator to size your Step 5 rebate stack
- Compare air sealing methods for 1.0 ACH50 builds
- Review wall assemblies for double-stud and exterior-insulated options