Industry & Code
Heat Pumps and HRV in a Modern Burnaby Custom Home: What the Code Now Expects
Cold-climate heat pumps and balanced ventilation aren't the upgrade anymore — they're the baseline. Here's how they integrate in a current Burnaby custom home, and what to ask your mechanical designer.
A decade ago, a heat pump in a Burnaby custom home was an upgrade choice. A heat-recovery ventilator was a Passive House feature. Today, both are the baseline. The combination of the BC Energy Step Code reaching Step 5 for new residential construction, the Zero Carbon Step Code emissions tiers, and the airtightness levels modern envelopes deliver has moved cold-climate air-source heat pumps and balanced mechanical ventilation from optional to expected.
This post is for the homeowner trying to understand what their mechanical system is going to look like, why those choices are being made, and what to ask the mechanical designer when the schematic drawings come back.
From optional to expected
Two changes drove this. First, the Step Code's tightening airtightness targets — Step 5 demands 1.0 air changes per hour at 50 pascals — make a passively ventilated, leaky house impossible to deliver. The home is sealed, and sealed homes need mechanical fresh-air supply. Second, the Zero Carbon Step Code's emissions levels favour electrification. A gas furnace can hit certain code paths but not the lower-emissions tiers. Heat pumps clear the bar without exotic equipment.
Both standards are documented in the provincial guidance on the BC Energy Step Code, and the 2024 transition has codified them as the new normal for permits in Burnaby, Vancouver, Surrey, Coquitlam, and most of the Lower Mainland.
Cold-climate heat pumps in Burnaby
A cold-climate air-source heat pump is what the rest of the industry now calls "a heat pump." The qualifier matters because older split heat pumps lost capacity below freezing. Modern variable-capacity units — typically using inverter-driven compressors and refined refrigerants — maintain rated capacity to roughly -15°C and continue producing useful heat well below that.
For Burnaby's climate, where the design heating temperature is around -7°C and the coldest days each winter rarely drop below -10°C, a properly sized cold-climate heat pump handles the entire heating load without backup. We rarely specify electric resistance backup for new builds in Burnaby, Vancouver, or Coquitlam — the climate doesn't justify the cost. In Abbotsford or further into the Fraser Valley where colder snaps are more common, a small backup may be specified by the mechanical designer.
Heat pumps that meet the Natural Resources Canada cold-climate specification are the products we work with. The NRCan list is a useful filter. Beyond that, we look at HSPF (Heating Seasonal Performance Factor) and SEER2 (Seasonal Energy Efficiency Ratio) — higher is better for both — and at sound levels at the outdoor unit, which matter on tight Burnaby Heights or Brentwood lots where the unit will sit close to a neighbour.
Sizing right with CSA F280-12
Heat pump performance is a function of correct sizing. Oversized units short-cycle, run inefficiently, and fail to dehumidify in summer. Undersized units run continuously and never quite catch up. The standard for residential sizing in Canada is CSA F280-12, and any mechanical designer worth working with will produce a CSA F280-12 calculation for the specific home, not a rule-of-thumb tonnage based on square footage.
The calculation considers wall and roof insulation, window areas and U-factors, infiltration assumptions, internal gains, and the specific heating and cooling design temperatures for the location. For a Step 5 Burnaby custom home of 3,500 sq ft, the calculated heating load is often less than half of what a rule-of-thumb would predict — because the envelope is doing more work than older homes did. A 3-ton heat pump that would have been right-sized for a 1980s build of the same size is now oversized.
We require a stamped CSA F280-12 calculation as part of the mechanical drawings. So does the City. The calculation is the basis for the equipment selection, the ductwork design, and the energy model for Step Code compliance.
Ducted vs ductless
A heat pump can deliver to the home through ductwork (ducted, central system) or through individual room heads (ductless, mini-split). Both work. The choice is design-driven.
Ducted is the default for new Burnaby custom homes for several reasons:
- Whole-house air filtration through a single high-quality filter
- Cleaner aesthetic — no wall-mounted heads in living spaces
- Easier integration with the HRV's distribution network
- Better humidity control on summer cooling days
- Single piece of equipment to maintain
Ductless has its place. It's the right call when:
- Renovations make running ductwork impractical
- Specific zones need independent control (a home office, a guest suite over a garage)
- Architecture is too sculptural for a hidden duct chase
For most ground-up custom homes in Burnaby, we specify ducted with a small number of dedicated zones. Multi-zone ducted systems with VAV (variable air volume) dampers are common where the architecture demands fine-grained control.
The mechanical decision people regret most isn't the equipment brand. It's the duct layout. Ducts that are forced to bend around structure they were never designed for don't deliver the air the model said they would.
— Sanj Aggarwal, CHBA BC Master Residential Builder
Why HRV/ERV becomes mandatory
When the envelope is sealed to 1.0 ACH50, the home cannot ventilate naturally. Bath fans pulling stale air out of a bathroom create a partial vacuum that has nowhere to draw replacement air from — except through the ducts that don't exist or through the few unintentional leaks the airtightness target was meant to eliminate.
The solution is balanced mechanical ventilation. A heat-recovery ventilator (HRV) or energy-recovery ventilator (ERV) supplies fresh air to bedrooms and living spaces, exhausts stale air from kitchens and bathrooms, and recovers heat (HRV) or heat plus humidity (ERV) from the outgoing stream. The unit runs continuously at low rate, with boost modes during showers and cooking.
In Burnaby's climate, an HRV is generally the right call for new construction. The west coast's mild humidity year-round doesn't demand the moisture transfer that an ERV provides; in mid-winter, an ERV can hold a little too much humidity inside, increasing condensation risk on cold surfaces. Drier interior climates (the Fraser Valley in summer) sometimes argue for ERV, and very airtight homes with high occupant density also benefit. The mechanical designer makes this call per project.
Sizing follows HRAI ventilation guidelines and the requirements in CSA F326. The HRV's distribution network is sized and balanced like any other ductwork — and on tight envelopes, a poorly balanced HRV is a comfort complaint waiting to happen.
Commissioning and balancing
Ventilation systems don't deliver design performance until they're commissioned. Commissioning is the formal process of measuring airflow at every supply and exhaust grille, adjusting dampers to match the design intent, and documenting the result. It's required as part of the mechanical scope on Step Code compliant homes.
The blower-door test verifies envelope airtightness. The commissioning process verifies ventilation airflow. Both happen near the end of construction. Both produce documentation that goes to the energy advisor for the Step Code compliance file.
We've seen homes where the mechanical equipment was right but the airflow was wildly off because no one balanced the system at completion. The owners moved in with the wrong air patterns and lived with cold rooms or noisy supply registers for years. Commissioning is the small step that prevents this.
Choosing a mechanical designer
A mechanical designer for a Step 5 Burnaby custom home is doing more than picking equipment. They are:
- Producing the CSA F280-12 calculation
- Designing the duct and HRV distribution network
- Selecting the heat pump and HRV/ERV based on the calculation
- Coordinating with the energy advisor on the Step Code energy model
- Producing the commissioning protocol
- Reviewing the installer's work in the field
The right designer has done this on Burnaby and Vancouver custom homes in the current code era. Older HVAC contractors who have not updated their methods will sometimes propose oversized equipment, exhaust-only ventilation, or no commissioning. Each of those is a flag.
What to ask your mechanical designer
When the mechanical schematic comes back, the questions worth asking:
- Where's the CSA F280-12 calculation, and what design temperatures did you use?
- What's the heat pump's rated capacity at -10°C, not just at 8°C?
- Is the HRV ducted independently or sharing the heat pump's ductwork?
- What's the commissioning plan and who does it?
- How will the system be controlled — single thermostat, zoned controls, smart-home integration?
For more on the envelope side of the same conversation, our companion piece on Step Code Step 5 covers the airtightness and thermal envelope decisions that drive heat pump sizing. For the durability conversation that the equipment is part of, why we don't believe in builder-grade covers our take on long-term value.
If you're looking at a mechanical proposal for a Burnaby, Vancouver, or Coquitlam custom home and want a second read before you sign off, reach out. The mechanical drawings are technical, but the questions a homeowner needs to ask are accessible — we'll walk through them with you.
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