Energy and Carbon Emissions Savings Benefits of Roof Replacements (Canada)

For most non-residential buildings located in Canada, the roof surface (often a low-sloped roof) comprises the largest single side of the building's thermal envelope. This large, opaque surface creates an opportunity to cost-effectively improve building energy performance during roof replacement projects. Where an existing roof contains insulation entirely above the deck and requires replacement, industry best practices in Canada encourage that the replacement roof system comply with minimum thermal envelope insulation levels required for new construction. For most existing buildings, upgrading the roof insulation during full roof replacement projects can significantly decrease whole-building energy use and reduce associated costs and carbon emissions. Understanding these benefits can help building owners make informed decisions that maximize the savings opportunities during alteration projects.

PIMA worked with the globally-recognized firm, ICF International, to quantify the benefits of energy code-congruent roof replacements in terms of energy and carbon emissions savings for the following common building types: primary school, retail store, strip mall and small office (source: U.S. Department of Energy (DOE) prototype buildings). The studied buildings were located in reference cities representing Climate Zones 4 through 7A as described in the National Energy Code of Canada for Buildings 2020. The results of this independent analysis demonstrate that increasing levels of roof insulation installed entirely above deck can help building owners cost-effectively reach energy reduction goals while cutting costs and carbon emissions in the process. Specific findings from the report include:

• For all building types and climate zones modeled, the reduction in natural gas used for space heating as a result of increased roof insulation was the primary driver for absolute energy savings.
• Roof replacement projects that feature enhanced levels of roof insulation are economical under a range of various conditions when analyzed from a life-cycle cost perspective.
• Energy-efficient roof replacements can support a wide-range of building decarbonization policies, including reduced carbon emissions associated with building operations, the implementation of building performance standards for existing buildings, and electrification targets.
  

The fact sheets below summarize the energy and carbon emissions savings estimates for each of the modeled climate zones and the building types within each region. A copy of the complete ICF International research report can also be downloaded below.

Canadian Climate Zone 4 (Example City: Vancouver, BC)

Installing additional roof insulation during a roof replacement project for buildings located in Canadian Climate Zone 4 is estimated to generate whole-building energy savings of 4-8% annually depending on the building type. This translates into cumulative energy cost savings per square meter of $21.57 to $35.72 (CAD) and cumulative carbon equivalent emissions reductions per square meter of approximately 20 to 110 kg.

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Canadian Climate Zone 5 (Example City: Toronto, ON)

Installing additional roof insulation during a roof replacement project in Canadian Climate Zone 5 is estimated to generate whole-building energy savings of 6-10% annually depending on the building type. This translates into cumulative energy cost savings per square meter of $39.64 to $57.56 (CAD) and cumulative carbon equivalent emissions reductions per square meter of approximately 60 to 170 kg.

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Canadian Climate Zone 6 (Example City: Montreal, QC)

Installing additional roof insulation during a roof replacement project in Canadian Climate Zone 6 is estimated to generate whole-building energy savings of 6-11% annually depending on the building type. This translates into cumulative energy cost savings per square meter of $40.25 to $67.66 (CAD) and cumulative carbon equivalent emissions reductions per square meter of approximately 70 to 210 kg.

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Canadian Climate Zone 7A (Example City: Edmonton, AB)

Installing additional roof insulation during a roof replacement project in Canadian Climate Zone 7A is estimated to generate whole-building energy savings of 9-11% annually depending on the building type. This translates into cumulative energy cost savings per square meter of $54.99 to $84.40 (CAD) and cumulative carbon equivalent emissions reductions per square meter of approximately 120 to 250 kg.

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Research Report: Life-Cycle Benefits of Energy Code-Congruent Roof Replacements

The ICF International research report explains the methodologies used to generate the energy and carbon emissions savings estimates for the modeled climate zones and buildings. The report includes details on the baseline assumptions for the analysis as well as data that highlight the cost-effective opportunity presented by adding roof insulation during full roof replacement projects to reduce whole building energy use and associated operational costs and carbon emissions.

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