Natural Resources Canada (NRCan), a department of the Canadian federal government, develops policies and programs that enhance the contribution of the natural resources sector to the economy and improve the quality of life for Canadians.
As part of its mandate, NRCan works in the fields of housing, building, communities, industry, and transportation to help Canadians take advantage of the benefits of energy efficiency, such as lower energy costs, cutting emissions, improving operating performance, and increasing asset values. ENERGY STAR Canada is a voluntary partnership between NRCan and organizations in the public, private and not-for-profit sectors to promote energy efficiency. ENERGY STAR certification makes it easy for Canadians to make energy efficient choices that help them save money on energy bills, increase their competitiveness, and fight climate change.
NRCan manages a program to encourage higher energy performance for residential windows, doors, and skylights by offering ENERGY STAR and “Most Efficient” energy rating labeling for products that achieve specific levels of performance. The program is somewhat complex, with different levels for three Canadian climate zones plus a two paths to qualify for the energy rating label.
NRCan was considering several different options for updating the ENERGY STAR labeling levels. These included:
- Harmonizing the levels across Canada (effectively merging the three climate zones into one)
- Simplifying the paths to ENERGY STAR qualification (currently obtained by either achieving a specific U-factor or by achieving a specific Energy Rating based on a combination of U-factor, SHGC and leakage)
- Adopting several other combinations of performance specifications.
NRCan employed Posterity Group Navigator™ to model national energy savings and GHG reduction from changing ENERGY STAR rating levels for residential windows, doors and skylights over a 20 year period. The comprehensive analysis included 22 regions, 6 fuels, 4 dwelling types, 7 vintages, 12 end uses and dozens of ENERGY STAR measures. Steve Hopwood, Account Manager for ENERGY STAR within NRCan’s Office of Energy Efficiency was responsible for leading the analysis.
The performance criteria for windows, doors and skylights focus on three variables: leakage, U-factor (a measure of the rate of conductive heat loss per unit of window area), Solar Heat Gain Coefficient (SHGC) (a measure of solar heat gain as a fraction of solar energy striking the window). The analysis quickly zeroed in on assessing the potential energy savings across Canada for proposed new ENERGY STAR criteria with different combinations of just U-factor and SHGC levels.
To explore the opportunity to simplify the path to ENERGY STAR qualification, a total of 6 variations of U-factor and SHGC values were evaluated using Posterity Group Navigator™. Although the hope was to establish a single path to qualification, U-factor alone (with no Energy Rating path) provided the lowest energy savings relative to the current ENERGY STAR program. The variation that offered improved versions of both paths ultimately provided the highest savings. All other variations examined fell somewhere between these two.
Posterity Group Navigator™ has enabled NRCan to explore and communicate the detailed results of ENERGY STAR program changes in new ways. The model revealed that the proposed use of a common set of requirements across all climate zones had a varying impact in different regions. In colder zones, the proposed harmonization of ENERGY STAR performance levels would have a small impact. However in warmer zones the more stringent common national levels proposed would result in dramatic savings. The granularity of the model enabled NRCan to see these impacts separately and meant that, for example, the savings related to space heating versus air conditioning was also visible. If they wanted to discuss the potential savings for fenestration product improvements with an electric utility that serves one province, they have the ability to produce tables and charts that highlight that part of the results.
Based on the comprehensive analysis enabled by Posterity Group Navigator™, NRCan concluded that a hybrid option was the most attractive choice, combining most of the savings potential with flexibility for manufacturers to choose how they modify their products to comply. The second path to qualifying for ENERGY STAR, using the Energy Rating, was also worth retaining.
Going forward, NRCan intends to keep the model current for further uses such as assessing the potential for new national standards for fenestration products. It will also be valuable for evaluating other measures to improve residential building envelopes, and potentially other types of research questions within the department.