Netting Zero for Less

Alternate title: Key Performance Indicators for Low Carbon Buildings: A Proposed Open Building Standard for Canada (Abstract, research paper pending)

Andy Thomson, M.Arch., OAA, MRAIC – Thomson Architecture Inc.
Ted Kesik, Ph.D., P.Eng. – University of Toront

With so many building energy ratings systems to choose from; LEED, NZEB, Passive House, R2000, WELL, LBC, etc., the marketplace has become crowded and confusing, and legacy standards fail to incorporate current metrics such as specific Indoor Air Quality indicators or Embodied Energy/Exergy, Carbon and Water data. Many of these standards depend upon predictive modelling that is fraught with uncertainty, as actual performance data reveals a disparity between ‘what is’ and ‘what ought’ to be. Proprietary rating schemes furthermore cost owners/clients substantial sums to design, model and certify based on comparing their predictive model against increasingly outdated reference models, when in fact the reference models seldom ever benchmarked actual performance from the outset and do not reflect carbon targets that would reasonably comply with Canada’s international GHG emission reduction commitments.

This project proposes an Open Building Standard or OBS that considers data transparency and ease of audits and usability (it’s all in an open source spreadsheet format), that uses a post-occupancy method of certifying buildings based on actual performance data obtained from physical building attributes and utility bills. After all we don’t award Olympic Gold to Athletes until they have performed at their events, why should we award buildings silver gold or bronze before we see how they actually perform? This analysis results in a certification label that compares against provincial and/or federal benchmarks and federal climate change mitigation targets, and as targets progressively ratchet up – so does the standard.

Any existing building may be ‘certified’ using this approach, which relies on a qualified professional engineer or licensed architect to compile the data and accept professional liability for the accuracy of the data they submit. This approach promotes a universal standard that can compare a wide range of projects, from Part 9 Residential to Part 3 Commercial buildings. The standard can also be applied to new construction and/or buildings under design, by substituting actual performance data with temporary predictive modelling targets for TEUI, TEDI, GHGI and Embodied Carbon Ratio and Intensity (ECR/ECI in absolute i.e. 1:3 and kgCO2e/m2 terms, respectively), which must then be validated and confirmed post-occupancy.

Metrics for IAQ/EAQ can be added as integrated modules within the proposed certification standard, along with water usage, Renewable Energy Credit (REC) offsets, and broader atmospheric offset schema. The key metrics will be clearly defined to limit ‘gaming’ of the system (ie. buildings must report utility bills during regular occupancy periods and not when occupants are ‘on vacation’ or ‘pending a global pandemic’ for example. This completed spreadsheet can then be printed to produce a label that is legible even to lay people because it is based on a familiar ‘Nutritional Facts Table’ (Health Canada) type format. Label production is via the simple open-source spreadsheet that can be distributed to any OS platform, downloaded and completed by any qualified professional* at zero or minimal cost. (samples below)

As an open standard to be developed and deployed first in Canada, there is potential for this standard quickly gaining traction in the international market as there is a high demand for a low-cost, simple, open and transparent performance rating standard that is not proprietary, and that measures and compares actual vs. predicted performance. The proposed labelling program would be complementary and non- exclusive to any other building design, certification and/or labelling programs, thus improving its adoption rate while providing reliable and easy to understand evidence-based ratings for buildings.

*Qualified Professional is a defined term that is presently subject to harmonization between the NBC and
Provincial Codes. Please feel free to download the source files for the Open Building Standard below. Any questions around use or feature requests can be made in the comments field directly below this post.

Update 3.3 FACTS label additions:

The current iteration of the FACTS labelling tool adds a second tab to act as a source of reference values for a wide range of building codes and standards. This tool was modified to permit an objective analysis of the proposed National Building Code of Canada (NBC 2020) and the National Energy Code for Buildings 2020 (NECB), against the existing Ontario Building Code (OBC) SB10 and SB12 provisions for Energy Efficiency. While the tool is simple to use, it may not be easy to understand how the tool works. We have offered the following OAA Webinar: and we will continue to add all of the respective Tiers of the proposed 2020 National Energy Code for Buildings will as soon as they become available to us.

Creative Commons License for Use: CC-BY-NC-ND 2021 by Andy Thomson, OAA & Dr. Ted Kesik, P.Eng per:


Andy Thomson, M.Arch. OAA, MRAIC

Andy is the principal and founder of Thomson Architecture, Inc., a research-driven firm specialized in zero-emission and high performance buildings. A graduate of UBC’s School of Architecture in 2003, Andy’s 28 yrs of experience in Germany, the US and Canada in the field of green design & construction combined with his love of the outdoors, informs the work he does today. Andy is an OAA councillor, member of the City of Barrie’s Committee of Adjustment and several task forces such as the affordable housing and greenhouse gas emissions plans. Andy has also been a pioneer of integrating Building Energy Modelling, Carbon Accounting and Costing Systems into Building Information Systems and was involved in the development of the OAA’s calculator and Building Energy Ratings System (BERS).
When Andy isn’t glued to the computer, he can be found paddleboarding, cycling, or riding electric skateboards.

Ted Kesik, BASc (Ottawa), MASc, PhD (Toronto)

Ted Kesik is a professor of building science in the John H. Daniels Faculty of Architecture, Landscape and Design at the University of Toronto with a career focus on the integration of professional practice, research and teaching. He entered the construction industry in 1974 and has since gained extensive experience in various aspects of building enclosure design, energy modeling, quality assurance, commissioning, performance verification, and building systems integration. Professor Kesik’s research interests include resilience, sustainability, durability, high performance buildings, life cycle assessment and building performance simulation. His current research involves the development of design guidelines for low-carbon buildings that are resilient, sustainable and promote climate change adaptation. Dr. Kesik continues to practice as a consulting engineer to leading architectural offices, forward thinking enterprises and progressive government agencies. He remains actively involved in technical organizations and is the author of books, studies, reports and articles related to his areas of research and professional practice.


  1. UofT/Daniels SoA Thermal Resilience Design Guide v1.0:
  2. Canada Federal Green Building Strategy Discussion Paper:
  3. OAA TEUI Calculator:
  4. OAA TEUI Page:
  5. TEUI Tutorial Video:
  6. On the use of the reference building approach in modern building energy codes:


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