HRV & ERV Ventilation Design for Ontario Building Permits
As of January 1, 2025, Ontario's updated Building Code makes mechanical ventilation with heat or energy recovery mandatory in every new home. Your permit application requires a certified Mechanical Ventilation Design Summary — we design the system, select the equipment, and deliver a BCIN-stamped report in 48 hours. For the complete permit package including heat loss and duct drawings, see our full HVAC design service.
- Total Ventilation Capacity (TVC) calculation
- HRV or ERV selection & sizing
- Room-by-room supply & exhaust CFM
- Principal & non-principal exhaust design
- Mechanical Ventilation Design Summary (MVDS)
- CAN/CSA-F326 & SB-12 compliance confirmed
- BCIN designer stamp & signature
HRV or ERV Is Now Mandatory in Every New Ontario Home
Ontario harmonized its Building Code with the National Building Code 2020 on January 1, 2025. The updated OBC Section 9.32 now requires mechanical ventilation with heat or energy recovery in all new residential construction. An HRV or ERV is no longer optional — it is a code-required component, and your permit application must include a certified ventilation design summary documenting compliance with CAN/CSA-F326 and OBC SB-12. This is one of the most common reasons we see in our permit rejection guide — applications submitted without the MVDS are returned immediately.
The new OBC 2024 also tightens equipment performance requirements. HRVs and ERVs must now meet a minimum Sensible Recovery Efficiency (SRE) of 55% at -25°C — and for homes in Ontario's colder climate zones requiring SB-12 Tier compliance, the minimum SRE rises to 65% or higher. Selecting the wrong unit doesn't just fail the permit — it leaves your home under-ventilated and fails your energy efficiency compliance path. Our ventilation design specifies equipment that meets every requirement for your specific home, climate zone, and SB-12 path. Use our free design temperature tool to confirm your municipality's climate zone before ordering.
This is the question we get most often, and it has a definitive answer based on your climate zone and heating system. Here's exactly how to think about it.
- Recovers 55–80% of heat from outgoing stale air
- Exhausts indoor moisture — ideal for tight, well-insulated homes
- Better choice for gas or oil heated homes where indoor humidity can be high
- Generally lower upfront cost than ERV
- Simpler maintenance — single core to clean
- Works well in Ontario's cold winters — no moisture transfer freeze risk
- Recovers both heat and water vapour from outgoing air
- Retains more indoor humidity — better for very dry climates or electric heat
- Reduces humidifier load in winter for electrically heated homes
- Better for homes in milder climates where humidity retention is desired
- Transfers moisture both ways — reduces summer dehumidification load too
- Typically more efficient for cooling-dominated climates
Ontario's ventilation design follows CAN/CSA-F326 — the standard for residential mechanical ventilation systems. The calculation starts with your home's Total Ventilation Capacity (TVC), which is the minimum airflow (in L/s or CFM) your whole-home ventilation system must deliver based on the number and type of rooms in your home.
The TVC is then distributed room by room — your primary bedroom requires 10 L/s (21 CFM) of fresh air supply, each additional bedroom requires 5 L/s (11 CFM), and every other habitable space requires a minimum 5 L/s. Your HRV or ERV must be sized to meet the total of all these requirements simultaneously.
Exhaust design is equally important. Principal exhaust fans (kitchen, laundry, bathrooms) and non-principal exhaust locations must be documented, balanced against supply air, and confirmed to avoid negative pressurization — which can cause combustion backdrafting in homes with gas appliances. This is the part most installers skip and most building officials check carefully.
If your home has more than 5 bedrooms, a CSA F326 full design or Part 6 design is required rather than the simplified Section 9.32 approach. We handle both. For context on how ventilation fits into the complete permit package, read our guide on what Ontario permit applications must include.
| Room Type | Min. Supply (L/s) | Min. Supply (CFM) |
|---|---|---|
| Primary Bedroom | 10 L/s | 21 CFM |
| Each Additional Bedroom | 5 L/s | 11 CFM |
| Basement | 10 L/s | 21 CFM |
| Living Room | 5 L/s | 11 CFM |
| Dining Room | 5 L/s | 11 CFM |
| Family Room | 5 L/s | 11 CFM |
| Kitchen | 5 L/s | 11 CFM |
| Home Office | 5 L/s | 11 CFM |
Source: CAN/CSA-F326 Total Ventilation Capacity requirements. Your HRV or ERV must be sized to deliver the sum of all room requirements simultaneously.
The updated OBC now specifies minimum Sensible Recovery Efficiency (SRE) at -25°C for HRV and ERV equipment. The required SRE depends on your home's SB-12 energy compliance path. Selecting a unit that doesn't meet the required SRE will result in a failed permit submission. For ICF homes specifically, ICF construction changes the energy compliance path and SRE requirements — these builds typically qualify for higher tiers.
| OBC Compliance Path | Min. SRE at -25°C | Typical Application | Our Selection |
|---|---|---|---|
| SB-12 Prescriptive — Basic | 55% | Standard new homes meeting minimum OBC energy requirements | ✓ Always specified |
| SB-12 Prescriptive — Enhanced | 65% | Homes with higher window-to-wall ratios or lower insulation packages | ✓ Always specified |
| SB-12 Performance Path | Varies by model | HOT2000 energy modelling approach — specific unit required for compliance | ✓ Confirmed to model |
| ICF Construction | 65%+ | ICF homes inherently meet Tier 3/4 — higher SRE typically required | ✓ Tier-appropriate selection |
SRE values must be taken from the HVI Product Certification Directory at the unit's operating CFM. Our equipment selection verifies SRE at the actual operating airflow, not just the rated airflow — a distinction that catches many off-the-shelf selections.
Everything your Ontario building permit application needs for mechanical ventilation compliance — in one stamped package.
Total Ventilation Capacity Calculation
Room-by-room TVC calculation per CAN/CSA-F326, showing the minimum ventilation airflow for your specific home layout and bedroom count.
HRV or ERV Selection & Sizing
Equipment recommendation from the HVI Product Certification Directory, confirmed for your TVC requirement, climate zone SRE minimum, and SB-12 compliance path.
Supply & Exhaust Air Distribution
Room-by-room supply and exhaust airflow assignment, confirming balanced ventilation and no negative pressurization risk near combustion appliances.
Principal & Non-Principal Exhaust Summary
Documentation of all exhaust fan locations — kitchen, bathrooms, laundry — with airflow rates and confirmation that exhaust is interlocked correctly with the HRV/ERV operation.
Mechanical Ventilation Design Summary (MVDS)
The OBC-required form consolidating all ventilation design data into the standardized format your building department expects. Ready to submit with your permit package in any Ontario portal.
BCIN Stamp & Signature
All documents stamped by our BCIN-registered HVAC designer — the legal requirement for permit submission. Pairs naturally with your CSA F280 heat loss report or full HVAC design package.
Questions specific to ventilation design — for permit package questions see our Full HVAC Design page. For the full list of what Ontario permit applications must include, read our permit rejection guide.
Is an HRV or ERV required in all new Ontario homes as of 2025?
Yes. Ontario's updated Building Code, effective January 1, 2025, requires mechanical ventilation with heat or energy recovery in all new residential construction under Part 9. Permit applications submitted without a ventilation design summary documenting HRV or ERV compliance will be returned as incomplete. This is one of the most common rejection causes we document in our permit rejection guide.
Can my HVAC installer just pick an HRV without a design?
Your installer can select and install an HRV, but the permit application requires a certified Mechanical Ventilation Design Summary — a specific form documenting TVC calculations, equipment selection justification, SRE confirmation, and exhaust design. This form must be stamped by a BCIN-registered designer. An installer's product recommendation alone does not satisfy the permit requirement. This is the same reason a CSA F280 heat loss report requires a BCIN stamp.
What is Sensible Recovery Efficiency and why does it matter?
SRE measures how effectively an HRV or ERV transfers heat from outgoing stale air to incoming fresh air. Ontario's updated OBC now requires a minimum 55% SRE at -25°C — a standard that screens out lower-performing units. For ICF homes or homes on enhanced SB-12 compliance paths, the requirement rises to 65%. For the coldest climate zones like Muskoka's Zone 7, meeting the SRE requirement at operating airflow — not just rated airflow — is critical.
My home has 6 bedrooms. Does that change anything?
Yes — homes with more than 5 bedrooms cannot use the simplified Section 9.32 ventilation design approach. They require a full CAN/CSA-F326 design or a Part 6 design. This is a more detailed calculation, but we handle both. Let us know your bedroom count when requesting your quote via our contact page and we'll confirm the scope and pricing.
Can I get ventilation design as a standalone service or does it have to be part of a bigger package?
Both options are available. If you already have a CSA F280 heat loss report from us or from another provider, we can produce the ventilation design as a standalone add-on for $295. If you need the complete mechanical permit package, our Full HVAC Design package includes ventilation design alongside duct drawings, equipment schedule, and Schedule 1 form for $695.
Do ICF homes have different ventilation requirements?
ICF homes are very airtight — typically achieving air leakage rates well below code minimums. This makes proper HRV/ERV design even more critical, because there is no incidental air leakage to supplement ventilation. ICF homes also typically qualify for SB-12 Tier 3 or Tier 4 compliance, which requires higher SRE equipment. If you're building an ICF home — particularly through icfhome.ca in Simcoe County or Georgian Bay — we're well-versed in the specific requirements for these builds. For general ICF heating system context, read the best heating systems for ICF homes.
Your permit application won't pass without it. Get a certified ventilation design that meets every OBC 2024 requirement — stamped and ready to submit. Pair it with our CSA F280 heat loss report for everything your permit needs in one package.
- TVC calculation per CAN/CSA-F326
- HRV or ERV selection — SRE verified at operating CFM
- SB-12 compliance confirmed for your path
- Mechanical Ventilation Design Summary (MVDS) included
- Principal & non-principal exhaust documented
- BCIN designer stamp & signature
- Delivered within 48 hours of payment
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Ventilation design is almost always needed alongside one or more of these services for a complete Ontario permit submission.