OBC 2024 HVAC Changes Ontario: What Changed for Residential Mechanical Permits — and What Stayed the Same
The Ontario Building Code 2024 (OBC 2024) came into force January 1, 2025, with full enforcement for all new building permit applications from April 1, 2025. For residential HVAC and mechanical systems, OBC 2024 made meaningful additions to the permit documentation requirements — most significantly the mandatory Mechanical Ventilation Design Summary (MVDS) — while leaving the foundational CSA F280 heat loss requirement and BCIN stamping requirements unchanged.
This guide is a clear, practical summary of what OBC 2024 changed for residential HVAC permits in Ontario, what the key dates are, and what a complete OBC 2024 compliant permit package now includes. If you submitted permits under the previous code and are now building under OBC 2024, this is your reference. For the complete HVAC permit requirements, see our HVAC permit requirements guide.
OBC 2024 Comes Into Force
OBC 2024 is the applicable building code from this date. New home applications submitted from this date are subject to OBC 2024 requirements — including the mandatory MVDS. Transitional provisions allowed some applications to proceed under the previous code for a limited time.
Full Enforcement — All Applications Under OBC 2024
From April 1, 2025, all new building permit applications across Ontario are processed under OBC 2024. No transitional provisions remain. Applications submitted without the MVDS are returned as incomplete. This is the enforcement date referenced by municipalities including Innisfil, Midland, and others who explicitly noted the April 1, 2025 deadline in their permit guidance.
Complete OBC 2024 Package Required Province-Wide
Every residential new home permit application in Ontario now requires the complete OBC 2024 package: CSA F280 heat loss, MVDS, mechanical drawings, Schedule 1, and BCIN stamp on every page. This applies to all 444 Ontario municipalities regardless of size. There is no municipal opt-out from the MVDS requirement.
| Requirement | Before OBC 2024 | Under OBC 2024 | Status |
|---|---|---|---|
| CSA F280 Heat Loss Calculation | Required under OBC Section 9.33.2.2 | Still required under OBC Section 9.33.2.2 | Unchanged — always required |
| BCIN Stamp on Design Documents | Required — every page of every document | Still required — every page of every document | Unchanged — always required |
| Schedule 1 Declaration | Required for all BCIN-stamped design work | Still required for all BCIN-stamped design work | Unchanged — always required |
| Mechanical Ventilation Design Summary (MVDS) | Not separately required as a permit document | Mandatory — must be submitted with permit application | NEW — mandatory from Jan 1, 2025 |
| HRV/ERV Installation | Required but not documented in permit package | Required and now must be documented in MVDS submitted with permit | Process changed — now part of permit documentation |
| SB-12 Compliance | Required at construction stage | Compliance path now documented in MVDS at permit stage | Earlier in process — documented at permit, not just construction |
The most significant practical change is the MVDS requirement. Before OBC 2024, a complete HVAC permit package consisted of the CSA F280 heat loss calculation, mechanical drawings, Schedule 1, and BCIN stamp. From January 1, 2025, that same package is incomplete without the MVDS. Any designer or contractor who says "the package I've always submitted is still sufficient" is describing a pre-OBC 2024 package. Under OBC 2024, that package will be returned. The MVDS is not optional, not conditional on project size, and not limited to certain municipalities — it is mandatory province-wide for all new home permits. See our MVDS guide for the full MVDS explanation and our HRV/ERV design service for the MVDS as a deliverable.
OBC 2024 added new requirements — it did not remove or relax existing ones. These three requirements were in force before OBC 2024 and remain exactly as they were.
CSA F280 — Unchanged Since 1997
OBC Section 9.33.2.2's requirement for a CSA F280 heat loss calculation has been in the code continuously since 1997. OBC 2024 did not modify it. Every new home with a heating system still requires a BCIN-stamped CSA F280 calculation at the local design temperature. See our F280 mandatory guide and our heat loss calculation service.
BCIN Stamp — Every Page
The requirement for BCIN credentials on every page of every design document submitted for permit is unchanged. OBC 2024 did not modify or relax the BCIN stamping requirement — if anything, building departments have applied it more consistently since OBC 2024's implementation brought renewed attention to the permit documentation requirements. See our BCIN guide.
Schedule 1 — Always Separate
The requirement for a separate Schedule 1 designer declaration — not incorporated into the drawings, not assumed from the BCIN stamp — predates OBC 2024 and is unchanged. Missing Schedule 1 continues to be one of the most consistent permit rejection causes across Ontario. See our Schedule 1 guide.
What is the most important HVAC change in OBC 2024?
The mandatory Mechanical Ventilation Design Summary (MVDS). Before OBC 2024, a complete HVAC permit package did not include the MVDS as a required document. From January 1, 2025, every new home permit application must include the MVDS documenting the HRV or ERV selection, ventilation capacity, SRE at -25°C, and SB-12 compliance path. Missing the MVDS returns the application before any technical review begins. See our MVDS guide.
When did OBC 2024 come into force?
January 1, 2025. Full enforcement for all new building permit applications followed from April 1, 2025. From April 1, 2025 onward, all new residential building permit applications in Ontario are processed under OBC 2024 with no transitional provisions remaining. The MVDS requirement applies to all applications submitted from April 1, 2025.
Does OBC 2024 change the CSA F280 heat loss requirement?
No — the CSA F280 heat loss calculation requirement under OBC Section 9.33.2.2 is unchanged by OBC 2024. It was mandatory before OBC 2024 and remains mandatory under OBC 2024. The design temperature, methodology, BCIN stamping, and room-by-room approach are all unchanged. What OBC 2024 added was the MVDS requirement on top of the existing CSA F280 requirement — not in place of it.
I submitted permits before OBC 2024 — what changes for my next project?
The main addition is the MVDS. Your next permit package needs everything your previous packages contained — CSA F280 heat loss, mechanical drawings, Schedule 1, BCIN stamp on every page — plus the MVDS documenting the HRV or ERV selection with SRE at -25°C and SB-12 compliance path. Every package we produce is OBC 2024 compliant by default — the MVDS is included as standard without needing to be requested separately.
Does OBC 2024 apply in every Ontario municipality?
Yes — OBC 2024 is provincial legislation that applies across all 444 Ontario municipalities. There is no municipal opt-out from the MVDS requirement or any other OBC 2024 change. Municipalities with their own additional requirements — Zoning Certificate pre-conditions, specific portal requirements — continue to have those in addition to OBC 2024. The code itself is province-wide.
Building under OBC 2024? Every package we produce is OBC 2024 compliant — MVDS included, CSA F280, Schedule 1, BCIN-stamped every page. 48 hours, province-wide.
Get Free Quote →Every package we produce meets OBC 2024 requirements as a default — the MVDS is included in every new home package, the CSA F280 is run at your confirmed local design temperature, Schedule 1 is included as a separate signed document, and BCIN credentials appear on every page. No retrofitting, no guessing, no missing documents. Upload your floor plans and we'll deliver in 48 hours. For the complete permit requirements, see our HVAC permit requirements guide.
- CSA F280 heat loss at your municipality's confirmed design temperature
- MVDS — HRV/ERV selection, SRE at -25°C, SB-12 compliance path
- Mechanical drawings — BCIN-stamped every page
- Schedule 1 — separate signed declaration
- OBC 2024 compliant · Flat-rate · 48h delivery · Province-wide