BC Zero Carbon Step Code: What Builders Need to Know About Emission Levels

The BC Energy Step Code has been shaping how homes are built in this province since 2017. But the Energy Step Code only measures how much energy a building uses. It does not measure where that energy comes from or how much carbon it produces. That is the gap the Zero Carbon Step Code fills.

If you are a Part 9 residential builder in BC, the Zero Carbon Step Code is the second half of the compliance picture. It introduces Emission Levels (EL-1 through EL-4) that progressively restrict greenhouse gas emissions from buildings, with a clear trajectory toward eliminating fossil fuel heating systems by the end of this decade.

Here is what the Zero Carbon Step Code means for your business, your builds, and the mechanical systems you specify.

What the Zero Carbon Step Code Actually Is

The Zero Carbon Step Code is a companion framework to the BC Energy Step Code. While the Energy Step Code sets performance targets for energy efficiency (airtightness, TEDI, MEUI), the Zero Carbon Step Code sets targets for carbon emissions from building operations.

It uses four Emission Levels:

• EL-1: Measure and report greenhouse gas intensity (GHGI). No emissions cap. This is a “measure-only” step that requires your energy model to calculate and disclose the building’s expected carbon emissions.
• EL-2: A modest emissions cap. Buildings must meet a greenhouse gas intensity limit, which effectively discourages the least efficient fossil fuel systems but still allows gas heating in many configurations.
• EL-3: A tighter emissions cap that makes it very difficult to comply with a natural gas furnace or boiler as the primary heating system. Heat pumps become effectively mandatory at this level for most building designs.
• EL-4: Near-zero operational emissions. Fossil fuel space heating and hot water are essentially eliminated. Buildings at this level run on electricity (or approved low-carbon energy sources) for all major end uses.

The greenhouse gas intensity metric (GHGI) is measured in kg CO2e/m2/year. It accounts for the carbon intensity of the fuel sources your mechanical systems use. In BC, electricity is very low-carbon (hydroelectric), so electric heating systems score extremely well. Natural gas produces roughly 180 g CO2e per kWh of delivered heat compared to about 11 g CO2e per kWh for BC grid electricity. That 16:1 ratio is the fundamental reason the Zero Carbon Step Code pushes buildings toward electrification.

How It Differs from the Energy Step Code

This is the distinction that matters most for builders: the Energy Step Code and the Zero Carbon Step Code are separate compliance tracks that work in parallel.

The Energy Step Code (Steps 1 through 5) measures how efficiently your building uses energy, regardless of fuel source. A gas furnace in an extremely well-insulated house can still achieve good TEDI and MEUI scores at lower steps. The Energy Step Code answers the question: “How much energy does this building need?”

The Zero Carbon Step Code (EL-1 through EL-4) measures how much carbon your building emits from the energy it uses. It answers the question: “How clean is that energy?”

A building must comply with both tracks. Right now, provincially, that means meeting at least Step 3 on the energy side and EL-1 on the carbon side. But these requirements are ratcheting up on separate timelines, and some municipalities are ahead of the province on both.

The practical takeaway: you cannot solve the Zero Carbon Step Code through envelope performance alone. A house with R-40 walls, triple-pane windows, and 1.0 ACH50 will still fail higher emission levels if it heats with natural gas. Conversely, an all-electric house with mediocre insulation might pass the emission level but fail the energy step. You need to hit both targets.

Current Requirements and the Path to 2030

As of March 2025, the provincial baseline for Part 9 residential buildings is:

• Energy Step Code: Step 3 (mandatory province-wide)
• Zero Carbon Step Code: EL-1 (measure and report only)

Here is the expected trajectory:

Year	Energy Step	Emission Level	What It Means
2023	Step 3	—	Energy efficiency baseline
March 2025	Step 3	EL-1	Carbon reporting begins
Expected 2027	Step 4	EL-2 or EL-3	Gas heating becomes difficult
~2030	Step 4/5	EL-4	Fossil fuel heating effectively ended

The exact timeline for EL-3 and EL-4 adoption will depend on provincial regulation updates and consultation outcomes. But the direction is clear and irreversible. The province has committed to aligning the building code with its CleanBC targets, which call for all new buildings to be “zero carbon ready” by 2030.

For a deeper look at the energy side of this timeline, see our Step Code timeline guide.

What Each Emission Level Means for Heating Systems

This is where the Zero Carbon Step Code hits your build budgets and mechanical specifications.

EL-1 (current): No restrictions on heating fuel. Your energy model must calculate GHGI, and the number appears on the compliance report, but there is no pass/fail threshold. You can still install a high-efficiency gas furnace. The purpose of EL-1 is to get the industry accustomed to tracking emissions and to establish baseline data.

EL-2: The GHGI cap begins to bite. For a typical 2,000 sq ft home in Climate Zone 5 (Okanagan/Kamloops), the cap is expected to sit around 10-12 kg CO2e/m2/year. A 96% AFUE gas furnace as the sole heating system will push most designs over this limit. But a hybrid system (heat pump with gas backup) can often squeeze under. This is the level where FortisBC’s hybrid pathway becomes relevant.

EL-3: The GHGI cap drops to roughly 3-5 kg CO2e/m2/year (exact thresholds vary by climate zone). At this level, natural gas as a primary heating fuel is effectively off the table. You need a heat pump for space heating. Gas may survive only for fireplaces or cooking in some configurations, and even that depends on the overall emissions budget.

EL-4: The GHGI target approaches zero for space and water heating. Full electrification is the standard path. Cold-climate air-source heat pumps (ccASHP) or ground-source heat pumps for space heating, heat pump water heaters for DHW, and electric cooking. Some designs may still use a small amount of renewable natural gas (RNG) or green hydrogen if available, but for practical purposes, EL-4 means all-electric.

For detailed guidance on heat pump selection and HVAC system design for Step Code compliance, see our HVAC for Step Code guide.

The FortisBC Hybrid Heat Pump Pathway

FortisBC has been promoting a hybrid heat pump approach: an air-source heat pump handles the majority of heating load (roughly 80-90% of annual heating hours), while a natural gas furnace provides backup during the coldest periods. This approach reduces gas consumption by 70-80% compared to gas-only heating.

Under the Zero Carbon Step Code, hybrid systems have a limited but real window of viability:

• EL-1 and EL-2: Hybrid systems typically comply. The heat pump does most of the work, and the remaining gas use keeps GHGI within the cap at EL-2 for most building designs.
• EL-3: Hybrid systems become marginal. Whether a hybrid passes depends on the building’s envelope performance, climate zone, and how many heating hours the gas furnace actually runs. In milder climate zones (Vancouver, Victoria), a hybrid might still pass. In colder zones (Kamloops, Prince George), it likely will not.
• EL-4: Hybrid systems will not comply. The emissions cap is too tight for any meaningful gas combustion.

FortisBC offers rebates through its New Home Program that support both hybrid and full-electric configurations. If you are currently building with hybrid systems, the financial incentives are strong through 2027-2028. But if you are planning builds that will be completed after 2028, designing for full electrification now avoids costly mechanical retrofits later. See our FortisBC rebates breakdown for current incentive amounts.

Why Air Sealing Is Still the Key Lever

The Zero Carbon Step Code targets emissions, not airtightness directly. So why does air sealing matter?

Because tighter buildings use less energy. And buildings that use less energy produce fewer emissions, regardless of fuel source.

Here is the math: every reduction in ACH50 lowers your TEDI, which lowers the total heating energy required, which lowers your GHGI. For an all-electric home, a tighter envelope means a smaller heat pump, lower electricity consumption, and a lower GHGI score. For a hybrid home trying to stay under an EL-2 or EL-3 cap, a tighter envelope means fewer hours when the gas backup kicks in, which directly reduces emissions.

At Step Code 4 (expected 2027), you need 1.5 ACH50 or better. At Step 5, the target drops to 1.0 ACH50. These airtightness levels do double duty: they satisfy the Energy Step Code requirements and they make it dramatically easier to meet the Zero Carbon emission levels.

In practical terms, a home that achieves 1.0 ACH50 with a cold-climate heat pump will have almost no trouble meeting EL-3 or even EL-4. A home at 2.5 ACH50 with the same heat pump will have to compensate with more insulation, a larger heat pump, or both, and it may still struggle at EL-3 in colder climate zones.

Air sealing is the single most cost-effective way to improve both energy and carbon performance simultaneously. It is not either/or. It is the foundation that makes everything else work.

Municipality-Specific Zero Carbon Requirements

As with the Energy Step Code, some BC municipalities are moving faster than the province on emission levels.

Vancouver has been the leader. The City of Vancouver’s building bylaw already requires near-zero emissions for new Part 9 residential buildings, effectively mandating EL-3 or equivalent performance. If you are building in Vancouver, you are already operating in a near-fossil-fuel-free environment for new construction.

Victoria and North Vancouver have signaled intent to adopt higher emission levels ahead of the provincial schedule, with EL-2 or EL-3 requirements expected to come into effect between 2026 and 2028.

Kelowna, Kamloops, and other Interior municipalities are generally following the provincial timeline but are watching the Vancouver and Victoria experience closely. Builders in these markets should expect local amendments once the provincial EL-2 or EL-3 requirements are finalized.

The pattern is the same as it was with the Energy Step Code: coastal municipalities adopt first, Interior municipalities follow 1-3 years later, and the province eventually catches up. If you are building in multiple jurisdictions, designing to the most stringent requirement you expect to face in the next 2-3 years is the most cost-effective strategy.

What Builders Should Do Now

The Zero Carbon Step Code is not a surprise. The trajectory has been public and consistent for years. Here is how to position your business:

1. Get your energy advisor modeling GHGI now. Even though EL-1 only requires reporting, ask your advisor to show you how close (or far) your standard designs are from the EL-2 and EL-3 thresholds. This gives you a planning horizon.

2. Start specifying heat pumps as primary heating. If you are still defaulting to gas furnaces, begin transitioning to cold-climate air-source heat pumps (ccASHP) as your standard specification. The product availability, contractor familiarity, and rebate programs are all mature enough to support this shift today.

3. Tighten your air barrier. Aim for 1.5 ACH50 or better on every build, even if your current step code requirement is 2.5 ACH50. This gives you margin on both the energy and carbon sides and positions your homes for resale value as code requirements increase. Every tenth of an ACH you save today is emissions headroom tomorrow.

4. Understand the rebate landscape. FortisBC, BC Hydro, and the CleanBC program all offer incentives that reward low-carbon building. Stacking these rebates can offset a significant portion of the incremental cost of electrification. The window for hybrid system rebates is narrowing, while full-electrification incentives are increasing.

5. Talk to your mechanical sub-contractors. Make sure your HVAC partners are comfortable sizing and installing heat pumps, heat pump water heaters, and HRV systems for tight envelopes. The mechanical side of Zero Carbon compliance is where most builders will face the steepest learning curve.

6. Watch your municipality. Check with your local building department for any planned adoption of emission levels beyond the provincial minimum. Getting ahead of local amendments is always cheaper than scrambling to comply after they take effect.

The Zero Carbon Step Code is the final piece of BC’s building performance framework. Combined with the Energy Step Code, it creates a complete system: build tight, insulate well, heat with electricity. The builders who internalize this formula now will have a significant competitive advantage as the requirements ratchet up through 2030 and beyond.