Interested in participating? Read the latest information below and stay tuned for updates. Program details are subject to change until the City opens the program for applications.


The Deep Retrofit Challenge (the Challenge) is a competition-style program, funded by the Federal Government, which will support deep retrofit projects that significantly reduce greenhouse gas emissions in approximately 10 to 16 buildings in Toronto. Participating buildings will serve to demonstrate the deep retrofits needed to move buildings towards net zero emissions, with the goal of accelerating market adoption. Buildings are the largest source of greenhouse gas emissions today, generated primarily by the burning of fossil fuels for heating and hot water.

The Better Buildings Partnership is committed to ensuring that the application process is fair and transparent. All questions submitted to the City about the Challenge and the responses provided will be available via the Questions and Answers document on this web page – see below. All meetings will be hosted by the City via public information sessions promoted via this web page and by email to past webinar registrants, our Partners, and through other City channels. City staff are unable to meet privately with parties interested in participating in the Challenge prior to application approval.

To be considered for the Challenge buildings must be located within Toronto and be an Ontario Building Code Part 3 building (i.e. greater than 600m2 or greater than three storeys). The following building types would be eligible to participate:

  • Multi-unit residential buildings (including condominiums, apartments, etc.)
  • Commercial office buildings.
  • Mixed-use buildings (residential and commercial, including residential over commercial).

The Challenge will serve as a catalyst to accelerate deep energy retrofits in support of the City’s Net Zero Existing Buildings Strategy, which together with the City’s TransformTO Net Zero Strategy aims to reduce emissions from buildings and all other sectors in Toronto to net zero by 2040.

If you have a question about the Deep Retrofit Challenge, please follow these steps:

  1. Submit your question to
  2. Staff will respond to your question within 2-3 business days.
  3. Staff will post the response to the Questions and Answers document—see below. Updates with new questions and answers will be done on a weekly basis.

Please note: the following information is subject to change when applications launch and final program rules are released.

Participants selected to participate in the Challenge will receive an incentive equal to 25 per cent of their total project costs up to a maximum of up to $500,000 (depending on gross floor area and emissions reduction) to offset the incremental design and construction costs required to achieve a deep retrofit and maximize emissions reductions.

The incentive will be disbursed at the following stages: 1) design; 2) construction; and 3) post-retrofit performance evaluation, based on measured emissions reductions once the project is complete.

Retrofits should aim to reach an 80 per cent emissions reduction or greater over current building emissions, in alignment with the City’s target to reduce emissions to net zero by 2040. At a minimum, the retrofit shall target a 50% reduction in total energy use intensity and a 50% reduction in greenhouse gas (GHG) emissions compared to the pre-retrofit baseline.

Projects must utilize solutions that have a 20-year payback period or better. Calculation of savings will be based on operational energy and emissions. Retrofits must follow a comprehensive whole-building approach that considers the building as a single, integrated system and how components of the building work together.

Challenge participants will be required to:

  • Provide a calibrated pre- and post-energy model using EnergyPlus, EQuest, or similar software.
  • Participate in a design charrette and other workshops or training organized by the City to identify various energy and environmental improvements that may be achieved with their deep retrofit and opportunities to advance the design.
  • Agree that the City can make the details of their deep retrofits publicly available, including utility energy use and costs, designs, and project costs, to help drive uptake of similar retrofits. Projects will be featured in case studies and recognized for early transformative action.
  • Calculate projected embodied carbon for major construction materials during the design phase (embodied carbon will not be factored into the performance incentive calculation).
  • Agree not to apply for any rent increases above the guideline as identified in the Residential Tenancies Act in connection with any portion of improvements funded through the Challenge.
  • Submit quarterly Progress Reports and grant the City of Toronto access to the Building to verify progress status.
  • Provide an approach that is replicable to similar building types across the City and across similar climates within Canada.
  • Participate in media event(s) and/or advertising campaigns promoting the Deep Retrofit Challenge and the Participant’s Project, including the building, technologies, etc.
  • Participate in the initial cohort of volunteers for the Net Zero Existing Buildings Strategy actions 1-3, which include:
  • Annual emissions (and energy) performance reporting, public disclosure and labelling
  • Greenhouse gas emissions performance targets
  • Performing energy and emissions audits and tune-ups (at regular intervals)

In addition, projects must:

  • Achieve a minimum 50 per cent reduction in greenhouse gas emissions (operational emissions).
  • Achieve a minimum 50 per cent reduction in total energy use intensity.
  • Demonstrate a 20-year payback period or better.
  • Be located within the city of Toronto.
  • Be holistic; not based on implementing a single measure. A comprehensive whole-building approach should consider the building as a single, integrated system with components working together. For example, a holistic retrofit may include multiple components such as the building envelope, HVAC system, renewable energy system, building operations, etc.
  • Have an achievable project schedule and be able to meet an operational date allowing for IPMVP-compliant Measurement & Verification to be complete and evaluated before March 31, 2026. For most projects, this likely requires an operational date on or before January 31, 2025.
  • Be sufficiently far along to provide preliminary design information during the application process.
  • Be a renovation of an existing building that has been occupied within the 12 months prior to the application. Projects may include the expansion of an existing building, however, the Challenge incentive amount will only apply to retrofit costs incurred for the existing building.

Priority will be given to:

  • Buildings constructed prior to 2004.
  • Retrofits that incorporate additional components that support the City’s TransformTO Net Zero Strategy (EV chargers, waste management, active transportation, etc.)

Eligible Costs (subject to change):

  • Calibrated pre- and post-retrofit energy modelling;
  • Air tightness testing;
  • Calculation of embodied carbon impact;
  • Air sealing
  • Insulation to increase R-Value;
  • High-performance triple-pane windows;
  • Electric heat pumps (ground or air source) for space and water heating;
  • Energy recovery (ventilation, drain, or equipment);
  • Renewable electricity generation;
  • Building controls and more

Participants may also apply to the City’s Energy Retrofit Loan (ERL) and High-Rise Retrofit Improvement Support (Hi-RIS) programs to assist in funding the projects, as well as to other incentive programs.

A deep retrofit is an extensive, holistic overhaul of a building’s systems, utilizing best practices with the goal of significantly reducing energy consumption and greenhouse gas emissions. A deep retrofit is either a step or a leap towards net zero emissions. To achieve the City’s net zero greenhouse gas emissions climate target almost all buildings in Toronto will be required to undergo deep energy retrofits.

A deep retrofit can deliver significant savings on energy costs as building energy usage is reduced by 50 per cent or more. Core components of a deep retrofit typically include:

  • improvements to the building envelope
  • fuel switching away from fossil fuel natural gas heating systems to electric heat pumps
  • modification of other parts of the HVAC system, building operations, renewable energy, and more

For example, the holistic upgrade of building systems could include air sealing and extra insulation, high-performance triple pane windows, electric heat pumps (ground or air source) for space and water heating, energy recovery (ventilation, drain, or equipment), renewable electricity generation, electric vehicle chargers, building controls and more.

The energy reduction from switching building heating systems away from fossil fuels to electric heat pumps alone is enormous; as air-source heat pumps are typically at least three times more efficient than the most efficient gas-fired heating systems. Ontario’s electricity system is relatively low-emissions meaning any fuel conversion from fossil fuels to electricity will result in large emissions reductions.

To achieve the City’s net zero greenhouse gas emissions climate target almost all buildings, old and new, will need to switch away from fossil fuels to clean electricity. Most buildings will need envelope upgrades, although some of the newest, highest-performance buildings may already have high-performance envelopes and will only require fuel switching (buildings that only plan to undertake a single retrofit measure are not the target of the Deep Retrofit Challenge).

Applications for the Deep Retrofit Challenge are not yet open. In the meantime, please check out the ‘Introductory Webinar’ recording from May 26 in the accordion below to see how you can begin preparing your application.

On May 26, the City held an ‘Introductory Webinar’ for the Deep Retrofit Challenge, see the recording below and the question and answers from the webinar and other sources in the accordion below. The information provided in the ‘Introductory Webinar’ may contain outdated information, it is important to check this web page and the Questions and Answers document below for the most up-to-date information, including webinars, that take place once the application process begins.

More informational webinars will become available when applications open.

The Q&A Deep Retrofit Challenge (DRC) is a summary of the questions received as part of the virtual Deep Retrofit Challenge Introductory Webinar on May 26 or received via our Better Buildings Partnership e-mail ( Responses have been edited for clarity and will be updated on a weekly basis.

If you have a question you would like to submit, please follow these steps:

  1. Submit your question to
  2. Staff will respond to your question within 2-3 business days.
  3. Staff will post the response to the Questions and Answers document above. Updates with new questions and answers will be done on a weekly basis.