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SB-12 Performance Path vs prescriptive packages: a builder's guide
Ontario's Building Code gives you three ways to prove a new house is energy efficient enough. The right one can save you money on the build, or be the only way your design passes.
THE SHORT ANSWER
- Prescriptive: pick a compliance package from SB-12 (Ontario's energy efficiency standard for new houses)'s tables and match every component to it. Simple, but rigid.
- Performance Path: model the house's energy use and show it meets the required performance. Flexible, and mandatory when windows exceed 22% of wall area.
- Other acceptable methods: ENERGY STAR for New Homes (Version 12.6) and the 2012 R-2000 Standard.
The three routes compared
| Prescriptive packages | Performance Path | ENERGY STAR or R-2000 | |
|---|---|---|---|
| How you comply | Every component meets the values of one package for your climate zone and heating system | An energy model shows the proposed house meets the required performance | Build to and document the program standard |
| Flexibility | Low: no trade-offs between components | High: trade one feature against another | Moderate: program rules apply |
| Glazing | Up to 17% of wall area, or up to 22% with upgraded windows | Any amount; required above 22% | Per program |
| Paperwork | Package selection on the energy efficiency design form | Energy model and report by a qualified modeller | Program documentation and testing |
| Extra value | None beyond compliance | Can lower build cost; the model supports rebates and mortgage refunds | A recognized label buyers value; qualifies for CMHC Eco Plus |
How prescriptive compliance works
SB-12 sets out compliance packages by climate zone: Zone 1 for areas below 5,000 heating degree days, which includes the GTA, and Zone 2 for colder areas at 5,000 or more. Each package fixes values for insulation, windows, airtightness, heating and hot water equipment, and heat recovery ventilation. Choose a package and every component must meet or beat it.
Window area is the most common trap. Up to 17% of above-grade wall area, a package applies as written. Between 17% and 22%, you can still use a package but must upgrade window performance. Above 22%, prescriptive compliance is off the table.
How the Performance Path works
Instead of matching a table, a modeller builds an energy model of the house as designed and compares it with a reference house. If the proposed house performs at least as well, it complies, however you got there.
That freedom is where the savings are. Common trade-offs include:
- A more efficient furnace, heat pump or water heater in place of thicker wall insulation
- A tested, tighter building envelope earning credit that relaxes other requirements
- Larger window areas for designs where the view sells the house
- Equipment and assemblies your trades already use, instead of package-driven substitutions
The same model can support blower door testing, heating and cooling load calculations, and evidence for buyer programs such as CMHC Eco Plus, so one piece of work does several jobs.
Which route should you choose?
- Standard tract design, under 17% glazing: prescriptive is often fine, but model it once to see whether a cheaper combination passes.
- Custom homes, large windows, or unusual shapes: Performance Path.
- Selling energy efficiency: ENERGY STAR or R-2000, which also help your buyers claim mortgage insurance refunds.
- Multiple models or phases: model each model once and reuse the results across lots.
Need modelling, testing or a compliance package for permit? See our services for builders.
Sources: Ontario 2024 Building Code Compendium: SB-12 Energy Efficiency for Housing · OAA practice tip on SB-12. Always confirm requirements with your building department.
Quick answers
What is the SB-12 Performance Path?
The Performance Path uses energy modelling to show that your proposed house meets the energy performance SB-12 requires, instead of matching every component to a prescriptive package. It lets you trade one feature against another, such as better heating equipment for less insulation.
When is the Performance Path required?
Under SB-12, a house whose windows and glass doors exceed 22% of the above-grade wall area must use the performance compliance route. Between 17% and 22%, a prescriptive package can still be used, but with upgraded window values.
Can ENERGY STAR or R-2000 replace SB-12 compliance?
SB-12 lists ENERGY STAR for New Homes (Version 12.6) and the 2012 R-2000 Standard among other acceptable compliance methods. Your building department will confirm what documentation it needs.