City of Toronto Launches Deep Retrofit Challenge to Accelerate Energy Efficiency in Existing Buildings to Help Meet Goal of Net Zero Emissions

April 27, 2022

The City of Toronto has announced the launch of the Deep Retrofit Challenge aimed at accelerating the reduction of greenhouse gas (GHG) emissions from existing buildings in Toronto.

Through the Challenge, the City will provide funding to support deeper-than-planned energy retrofits in 10 to 16 privately-owned buildings in Toronto, with the goal of accelerating emissions reductions and identifying pathways to net zero that can be replicated in other buildings. The Challenge is funded through a $5 million investment provided through Natural Resources Canada’s Green Infrastructure – Energy Efficient Buildings Program.

Projects will be selected through a competition-style process. Selected projects will receive a grant equal to 25% of their total project costs up to a maximum of up to $500,000 (depending on gross floor area) to offset the incremental design and construction costs required to achieve maximum emissions reductions.

Participants may also apply to the City’s Energy Retrofit Loan program and High-Rise Retrofit Improvement Support program to assist in funding their projects, as well as incentives available from other sources.

Eligible buildings include:

  • Multi-unit residential (more than six units or three storeys)
  • Residential condominiums (more than six units or three storeys)
  • Commercial office buildings
  • Mixed-use buildings
  • Residential over commercial (more than six units)


Eligible projects must:

  • Involve a deep retrofit of an existing, occupied building located in Toronto
  • Be aligned with the objectives of the City’s Net Zero Existing Buildings Strategy
  • Reduce GHG emissions by at least 50%
  • Reduce energy costs by at least 50%
  • Use an approach that is replicable to similar building types across the City and across similar climates in Canada
  • Provide a whole-building energy model for pre- and post-retrofit case studies
  • Meet a 20 year payback period or better
  • Be complete and operational by January 1, 2025


Projects must use a comprehensive whole-building approach, considering how components of the building work together as an integrated system, and may include measures such as:

  • Building enclosure improvements such as insulation, high performance windows and air sealing
  • Energy recovery (ventilation, drain or equipment)
  • Electric heat pumps (ground or air source) for space and water heating
  • Renewable electricity generation
  • Building controls


Buildings are the largest source of GHG emissions in Toronto today, generating approximately 57% of total community-wide emissions.

The retrofits funded through the Challenge are expected to result in approximately 1,750 tCO2e (tonnes of carbon dioxide equivalent) per year in emissions reductions starting in 2025 when the retrofits are complete, and will demonstrate deep retrofit pathways that building owners across Toronto can undertake to reduce emissions from their buildings.

Information from the projects, including designs, budgets and performance data will be open-sourced to drive case studies, technical reports and academic research that will help promote community knowledge of deep retrofits and facilitate the uptake of deep retrofits needed to reach the City’s net zero by 2040 target.

More information about the Deep Retrofit Challenge and next steps for interested building owners is available on the City’s Better Buildings Partnership webpage.

More information on the actions needed to bring buildings to net zero is available in the City’s Getting to Net Zero: Existing Buildings in Toronto webpage.