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Do I Need a Heat-Loss Calculation in Ontario? (Short Answer: Yes)
Heat-loss for your permit
CSA F280-12 | BCIN-stamped
OBC 9.33.2.2
Part of: Radiant & In-Floor Heating in Ontario · How radiant works
Do I Need a Heat-Loss Calculation in Ontario? (Short Answer: Yes)
If you’re building a new home in Ontario, the answer is yes – and it’s not optional. The Ontario Building Code requires a CSA F280-12 heat-loss calculation, stamped by a BCIN-registered designer, with every new-home permit application; your building department won’t accept the application without it. It’s also the document that sizes your heating, sets your radiant water temperatures, and keeps your equipment from being oversized. Here’s exactly what it is, what’s in the permit package, and how to get one done fast.
Yes – new homes
Required by code
CSA F280-12
The required method
BCIN-stamped
Must be certified
~$500-$700
Typical permit package
The short answer
For a new home in Ontario, yes – a heat-loss calculation is mandatory. Under Ontario Building Code Section 9.33.2.2, every new-home permit submission must include a heat-loss calculation done with the CSA F280-12 methodology, and the report must be stamped by a BCIN-registered designer. Municipalities won’t accept the permit application without it. For a renovation or addition that adds or changes heating, you usually need one too – confirm with your building department, because the threshold varies. Only a minor reno that doesn’t touch the heating system typically escapes it.
What a heat-loss calculation actually is
CSA F280-12 is the Canadian standard for figuring out exactly how much heat a home needs. It’s a room-by-room, wall-by-wall, window-by-window calculation of how much heat your house loses on a design-cold winter day (and gains in summer), based on your insulation, windows, air-tightness, orientation, and local climate. The output is a precise heating (and cooling) load in BTU per hour – the number that tells your designer what size of boiler, heat pump, or furnace you actually need, and for radiant, how to lay out the loops and what water temperature to run.
Why the code requires it – three jobs in one
1. Right-size the equipment (9.33)
The whole point is to stop the old habit of guessing big. An oversized furnace or boiler short-cycles, wastes fuel, and heats unevenly; an undersized one can’t keep up. The F280 load is the honest number everything else is sized from – including accurate heat-pump sizing for energy compliance under Section 9.36.
2. Ventilation (9.32)
The 2024 code requires mechanical ventilation with heat or energy recovery – an HRV or ERV – in every new home, and the permit needs a Mechanical Ventilation Design Summary (MVDS) documenting it per CAN/CSA-F326. Radiant heats, but it doesn’t ventilate, so this is a separate, required piece.
The third job is energy compliance: most Ontario new-home permits also need an SB-12 Energy Efficiency Design Summary (EEDS) showing the home meets the energy code. Together, these documents are how the municipality confirms your house will be comfortable, efficient, and code-compliant before a shovel goes in the ground.
What’s in the HVAC permit package
For a typical Ontario new home, the building department expects a BCIN-stamped package that usually includes:
| Document | What it does | Typical cost |
|---|---|---|
| Heat loss / gain (CSA F280-12) | The room-by-room heating and cooling load | from ~$250 |
| Mechanical / HVAC design | System layout, duct or loop design, equipment sizing | from ~$250 |
| Ventilation summary (MVDS) | HRV/ERV design per CAN/CSA-F326 | ~$100 |
| SB-12 Energy Efficiency Design Summary | Proves energy-code compliance | ~$100 |
| Complete package (typical home) | All of the above, BCIN-stamped, permit-ready | ~$500 – $700 |
Pricing varies with the provider and the complexity of the home (HVAC design pricing is commonly quoted for homes up to about 3,000 sq ft). The non-negotiable part is that every document is stamped by a BCIN-registered designer – that’s what makes it acceptable to the municipality.
Why radiant floor heating especially needs it
For radiant, the heat-loss calculation isn’t just a permit formality – it’s the blueprint. You literally cannot design a radiant system without it: the loop spacing, the water temperature, the number of zones, and whether any room needs a supplemental boost all come straight out of the F280 numbers. Size it wrong and you get the classic complaints – lukewarm floors, short-cycling, a room that never quite keeps up. Size it right and radiant disappears into the background and just works. The room-by-room load is exactly what tells us whether radiant will heat your house and how to set up the hydronic system.
The order that saves money: heat-loss numbers first, then the heat source, then the radiant design, then the install. Do it in that order and every dollar is sized to reality. Do it backwards – pick equipment, then hope – and you overpay for oversized gear and chase comfort problems later. The calculation costs a few hundred dollars and routinely saves thousands.
BCIN-stamped, permit-ready, fast turnaround.
Get your CSA F280-12 heat-loss + radiant design
Upload your plans and our heat-loss engineer emails you a price for the full BCIN-stamped, Cloudpermit-ready package – heat loss/gain, mechanical and radiant design, the ventilation summary, and the SB-12 form your municipality needs. It’s the one document that sizes everything and gets your permit moving. This is the work we do.
You can also sanity-check your own numbers first with our free heat-loss calculator – handy for early budgeting, though the permit still needs the stamped CSA F280-12 report.
When you might not need one
A handful of cases skip it, but verify with your building department before assuming: a minor renovation that doesn’t add or alter the heating system, like new flooring or cosmetic work, generally won’t trigger it. Replacing like-for-like equipment may not, depending on the municipality. But anything that builds a new dwelling, adds conditioned space, or changes the heating system almost always does. When in doubt, a quick call to your local building department settles it – and if you’re putting in radiant, you’ll want the calculation regardless, because the system can’t be designed without it.
Building in Georgian Bay or Simcoe County?
We produce heat-loss and mechanical paperwork and build the radiant to match – in our own ICF homes for 30+ years. Tell us about your project and we’ll call you back, usually within one business day, with a real plan and price. No cost, no obligation.
OK
You’re on the list!
Thanks – we’ll call you within one business day about your heat-loss and radiant project.
Questions about the permit paperwork? Get a one-on-one consult.
What your municipality needs, what the package costs, or how the heat-loss feeds your radiant design. We scope it on a quick call and send a secure payment link – you only pay once you know what you’re getting.
Building new? The HST rebate can cover a big slice
While you’re sorting the paperwork: a new build in Ontario likely qualifies for the enhanced HST rebate – up to $130,000 back if your build contract is signed before the deadline. Check your number before you commit.
Ontario HST Rebate | Deadline April 1, 2027
You Could Lose Up To $106,000 If You Don’t Start Before April 2027
Ontario’s enhanced HST rebate puts up to $130,000 back in a new-home builder’s pocket – but only if your build contract is signed before April 1, 2027. Miss that window and you fall back to the standard $24,000 rebate.
$0
Contract signed before Apr 1, 2027
$24,000
Signed after the deadline
$900,000
Miss the deadline and you forfeit
$0
Estimate based on Ontario’s 2026 enhanced HST rebate (Bill 114). Final eligibility is confirmed by a licensed rebate specialist – that’s what the free check is for. Full HST rebate details
Lower heat loss, simpler everything: ICF
The lower your heat loss, the smaller and cheaper your heating equipment - and the easier the F280 numbers make every downstream decision. An ICF home has remarkably low heat loss, which is why our own ICF homes run radiant on small, efficient equipment. See what ICF is, browse our ICF house plans (every one offered with the ICF + radiant package), run the ICF cost calculator, or check code with the OBC Code Navigator.
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Heat-loss calculator
Heat-loss calculations in Ontario: frequently asked questions
Do I need a heat-loss calculation for a building permit in Ontario?
For a new home, yes - it's mandatory. Ontario Building Code Section 9.33.2.2 requires a CSA F280-12 heat-loss calculation, stamped by a BCIN-registered designer, with every new-home permit application, and your building department won't accept the application without it. Renovations and additions that add or change heating usually need one too; confirm the threshold with your municipality.
What is a CSA F280-12 heat-loss calculation?
CSA F280-12 is the Canadian standard for determining a home's required heating and cooling capacity. It calculates, room by room and window by window, how much heat your house loses on a design-cold winter day (and gains in summer), based on insulation, glazing, air-tightness, and climate. The result is the precise BTU-per-hour load that everything else - boiler, heat pump, radiant loops - is sized from.
Does the heat-loss report need to be BCIN-stamped?
Yes. The Ontario Building Code requires the heat-loss calculation and the rest of the HVAC design documents to be prepared and stamped by a BCIN-registered designer. The BCIN stamp is what makes the package acceptable to Ontario municipalities; an unstamped spreadsheet won't pass.
What's in the HVAC permit package?
For a typical new home it usually includes the CSA F280-12 heat loss/gain calculation, the mechanical/HVAC design (system layout and equipment sizing), a Mechanical Ventilation Design Summary (MVDS) for the HRV/ERV, and an SB-12 Energy Efficiency Design Summary - all BCIN-stamped. Together they prove the home will be properly sized, ventilated, and energy-compliant.
Do I need an HRV or ERV too?
Yes - in a new Ontario home it's required. OBC Section 9.32 (2024) mandates mechanical ventilation with heat or energy recovery, so an HRV or ERV is part of the build, and the permit package needs a Mechanical Ventilation Design Summary per CAN/CSA-F326. Radiant heats but doesn't ventilate, so this is a separate, required system.
How much does a heat-loss calculation cost in Ontario?
As planning numbers, a heat loss/gain calculation starts around $250 and a mechanical HVAC design starts around $250 (commonly for homes up to about 3,000 sq ft), with the ventilation summary and SB-12 form around $100 each. A complete BCIN-stamped permit package for a typical Ontario home usually runs about $500 to $700. Pricing varies with provider and complexity.
Do I need one for a renovation or addition?
Often, yes - if the work adds conditioned space or adds/changes the heating system, a heat-loss calculation is generally required. A minor renovation that doesn't touch heating, like flooring or cosmetic work, usually isn't. The threshold varies by municipality, so confirm with your building department - and if you're adding radiant, you'll need the calculation regardless to design it.
Why does radiant floor heating specifically need it?
Because the heat-loss numbers are the blueprint for the radiant design. Loop spacing, water temperature, the number of zones, and whether any room needs supplemental heat all come straight from the F280 load - you cannot design a radiant system without it. Size it right and radiant just works; skip it and you get lukewarm floors and short-cycling.
What is SB-12 / the Energy Efficiency Design Summary?
SB-12 is Ontario's energy-efficiency supplementary standard for housing, and the Energy Efficiency Design Summary (EEDS) is the form that shows your home meets it - the insulation, windows, and mechanical efficiency package. Most Ontario new-home permits require it alongside the heat-loss and ventilation documents.
How long does it take, and how do I get one?
Once your plans are ready, a heat-loss and mechanical package is typically a quick turnaround - often within a couple of business days for a standard home. Upload your plans to our heat-loss engineer and you'll get a price for the full BCIN-stamped, permit-ready package; we can also design and build the radiant to match.
Note: code references (OBC 9.33.2.2, 9.32, 9.36, SB-12) and cost figures are general guidance, not legal or engineering advice. Requirements and thresholds vary by municipality and edition of the code - confirm with your building department and a BCIN-registered designer for your specific project.
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