Energy Modeling for Performance Path Building Code Compliance (Ontario Building Code SB12 3.1.2 & NBC 9.36)

Did you know that thoughtfully designed performance-based homes can use less energy, are more comfortable and have far better indoor air quality than minimum building-code-compliant homes? (e.g 2017 OBC SB12 3.1.1 PKG A1 to A6 or NBC 9.36). It IS possible to construct and maintain homes that cost less and are more energy efficient by applying performance compliance energy modeling and strong building science principles.

Through Performance Path compliance, builders and designers can find construction cost savings of $500 to nearly $2,000 per home.

Does this sound too good to be true? It's not, here are the facts:

There are two ways of meeting and exceeding the minimum energy efficiency levels within the 2017 Ontario Building Code SB-12 standards or National Building Code of Canada section 9.36 :

  • Option #1: Prescriptive Compliance

The builder or designer picks from a short list of compliance options such as insulation values for enclosures, U/ER values for windows and efficiency levels for HVAC components.

Options are limited and expensive, there's no construction cost optimization, and options often have negligible (or even negative) impacts on the actual comfort and efficiency of the home.

  • Option #2: Performance Compliance

Builder or designer works with a professional, registered energy evaluator to model the home, applying solutions, technologies and solid building science principles. This holistic design approach results in:

    • Design Flexibility
    • Construction Cost Reduction; Insulate or increase efficiencies where it really matters based on the geometry, climate, orientation, expectations and regional cost-effective technologies or building practices.
    • A More Comfortable & Healthy Home: Take advantage of better air barriers/air-tightness, efficient ventilation systems and implement better enclosure technologies that minimize drafts, reduce noise infiltration, ensure balanced comfort across all levels of the home and more.

The Building Knowledge Canada team works with numerous designers and builders across Ontario and Canada reducing the energy use of home designs to meet new building code standards, increasing the performance of the home, and doing it for less cost than the minimum building code!

Option 1: Performance Path (No Blower Door Test)

In this option, Building Knowledge Canada evaluates and optimizes the enclosure design, insulation and mechanical performance of each home using energy modeling software.

With this method, many designers and builders are often surprised to find their current specifications meet or exceed even the new Ontario Building Code requirements. Most notably, energy modeling allows the designer and builder to create their own energy solutions, taking advantage of local best practices, better performing building products and equipment, and favourable building geometry and orientation. For example, a designer may struggle to fit more insulation into the above grade walls due to loss of internal square footage or inability to accommodate garage and stair clearances. By eliminating the "prescriptively" required 1" to 2" of continuous exterior insulation and increasing the efficiency of the mechanical equipment and upgrading the window performance specifications, the designer maintains the valuable square footage and eliminates the clearance issues. This results in a design that uses less energy (lower utility bills and better comfort) than even the original prescriptive requirements.

Table 1 Example: Performance -No Blower Door Test

Option 2: Performance Path + Blower Door Test

This is the same as option one, with the exception that an air test is performed on the home prior to closing. For example, the prescriptive compliance packages of the OBC assumes homes have a normal-to-high air leakage rate for example of 3.0 ACH50 for singled detached and 3.5 ACH50 for attached homes. Most designers and builders are constructing homes that have robust air barriers which perform far better than the OBC assumed minimum levels.

As Canadians, we also know that:

  • Air leakage and infiltration can add 20% to 40% more heating/cooling load to a home
  • Air leakage/exfiltration of interior air (warm interior air leaking into the enclosure during cold temperatures) is a leading cause of moisture and decay inside walls, roofs and floors in North America Builders
  • Building codes across N. America are swiftly adopting air infiltration testing/blower door testing as a minimum code compliance requirement to ensure the durability, health and efficiency of homes and buildings.

As an example, a designer or builder can reduce the energy use of a common new, 2-story , 2,000 sq. ft. residence by simply building better, ensuring continuity of the Air Barrier and achieving better air-tightness (1.5 ACH50 to 2.5 ACH50). This level of air-tightness performance reduces energy use, drafts, sound infiltration and makes the enclosure last longer than this following list of prescriptive items combined:

  • Increasing attic insulation from R50 to R60
  • Increasing furnace efficiency from 92% to 98%+
  • Increasing wall insulation from R20batt to R24 batt.

Another example

of performance path optimization includes drain water heat recovery DWHR requirements in the OBC SB12 3.1.1 Prescriptive inclusions. DWHR is an excellent, passive technology that, like many other efficiency options, may or may not make sense to include in a homes design. Through performance compliance, the builder or designer can choose to apply an alternative method to achieve the efficiency of the home without using DWHR.

Table 2 Example: Performance -No Blower Door Test

There are many more examples where the Building Knowledge Canada team has worked with builders, architects and designers to determine what additional energy efficiency improvements, such as triple pane windows, energy recovery ventilation, under-slab insulation and highly efficient domestic hot water heating equipment may be used to meet or exceed the OBC SB-12 or NBC 9.26 reference design.

Option 3: ENERGY STAR® for New Homes Certification

We've saved the best for last (in our opinion). For those of you that are already certifying to ENERG

Y STAR®, congratulations! All your years of hard work constructing comfortable and durable homes is paying off.

For everyone else, this truly is a no-brainer, cost-effective choice. The preferred rating system for energy efficiency in homes, ENERGY STAR® homes are 20% more efficient than the building code. The little blue ENERGY STAR® label has a consumer recognition rate of 90%+ and helps buyers feel confident they are getting a well-built home that is 3rd party tested and inspected! When you choose to certify to ENERGY STAR® standards, you should expect to design to requirements like this:

Attic/Ceiling : R50/R31
Walls: R20+R5 sheathing
Windows: Zone 2 ENERGY STAR®
Basement: R20
Furnace: 95% afue
Hot water: 0.80/ 90% TE
HRV: 65% SRE
DWHR: 42% serving one shower
Fireplace: spark ignition
Air tightness test: 2.5ach detached /3.0 ach attached

So there are your path to performance options!

We hope this helps you make an informed decision. Moving towards performance compliance with energy codes is a great way to build better homes for less cost.

Please connect with our team and we'll arrange assistance immediately.

We can help you navigate the new codes, contact us today!