The OPA Measures and Assumptions Lists were created to provide best available information and consistent conservation program assumptions needed to estimate potential energy and demand savings which, in turn, serve as the basis for the design, implementation, and evaluation of conservation and demand side management programs.  Depending on various factors such as project size, ease of implementation or level of incentives, the estimation of resource savings may be approached in three different ways: prescriptive, quasi-prescriptive or custom approach. The prescriptive approach makes use of prescribed input assumptions that include default efficiencies for a type of equipment specified or annual operating hours for the type of building selected while the quasi-prescriptive approach makes use of key, measure-specific input assumptions (e.g. different annual operating hours for different type of buildings or different levels of efficiencies).  The custom approach is used when neither prescribing input assumptions nor providing key specific input parameters is sufficient in estimating the resource savings.  It is usually considered when project complexity is high, when very precise and accurate savings estimates are required, or when program budget and timeline are able to accommodate the implementation. Any new measures adopted to the lists require at least a minimum standard of substantiation. Substantiating involves identifying the base and high-efficiency case, the appropriate key input assumptions (i.e., equipment capacity, number of hours), calculation methods of energy and demand savings, effective useful life, incremental costs and measure assumptions used in other jurisdictions. This required depth of substantiation and documentation will ensure the integrity of the Measures and Assumptions Lists and make it a valuable resource for everyone in the electricity sector.  It made use of existing lists of inputs and assumptions, reports, technical literature and publications, and based on best information gathered and some new research, the lists were refined to be suitable and specific to Ontario. The OPA maintains Measures and Assumptions Lists under two categories: Prescriptive List -- is a collection of electricity conservation measures which present energy and demand savings using prescriptive input assumptions (PIAs).  The 2010 Prescriptive Measure and Assumptions Release 1 – January 2010 is a revised and updated version of 2009 Mass Market Measures and Assumptions List issued in April 2009. Quasi-Prescriptive List -- is a collection of electricity conservation measures which present key parameter inputs and a prescribed methodology for estimating resource savings.  A common quasi-prescriptive methodology is to prescribe energy and demand savings for a measure on a scalable basis (such as per unit-of-capacity or per hour-of-operation).  It includes equations requiring minimal inputs or lookup tables with pre-generated values. The 2010 Quasi-Prescriptive List is a revised and updated version of the 2009 Commercial and Institutional Measures and Assumptions List issued in November 2008.  . Revisions and updates to the Lists include revised values for some measure assumptions based on program evaluation feedback and measures’ research as well as the addition of new measures.

2010 Prescriptive Measures and Assumptions 2010 Quasi-Prescriptive Measures and Assumptions Download Previous Versions   2009 Mass Market Measures and Assumptions  2009 Commercial and Institutional Measures and Assumptions

Free Ridership Rates and Other Adjustment Factors Free ridership rates and other adjustment factors are not included in any of the OPA Measures and Assumptions Lists. For more information, please refer to the introduction in an any of the Lists.

Measure Updates

Measure updates will be posted as they become available. Prescriptive and quasi-prescriptive measures under review are listed in their respective List. Click here to receive Measure Updates.


Submisson Process for Measures

The OPA is continuously accepting nominations for updates to its Measures and Assumptions Lists. The measures may include: new measures, new measure ideas, and revisions to existng measure values.