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 receive a grant equal to 25 per cent of their total project costs up to a maximum of $500,000 (depending on gross floor area and building performance) to offset the incremental design and construction costs required to achieve maximum emissions reductions. The selected projects 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 in Toronto today, generated primarily by the burning of fossil fuels for heating and hot water.

Applications were accepted from August 26 to October 31, 2022. During this time, the City led two informational webinars (recordings available below), promoted the program via multiple channels and media, and answered all inquiries with interested parties (see Questions and Answers document below). To help ensure a fair and transparent application process, the City did not meet privately with parties interested in participating in the Deep Retrofit Challenge before application approval.

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 to address the climate crisis.

At this time, the City is reviewing all applications submitted. If you are interested in receiving updates about this program such as announcements about the selected participants, future case studies, and other news, please contact the Better Buildings Partnership team at and ask to be added to the mailing list.

Applications for the Deep Retrofit Challenge were accepted from August 26 to October 31, 2022 at 5 p.m. (Eastern Standard Time).

The following application materials were made available during that period:

Deep Retrofit Design Requirements

Deep Retrofit Projects must meet all of the following mandatory requirements:

  • Minimum greenhouse gas emissions reduction of 50%
  • Minimum energy use intensity reduction of 50%
  • Maximum payback of 20 years.

Additional Project Requirements

  • Use a comprehensive whole-building analysis approach to deep retrofits.
  • Meet complete the Deep Retrofit Project and be operational on or before January 31, 2025.
  • Be a retrofit of an existing building that has been occupied (not vacant) within the 12 months prior to the Application submission.
  • Must not have commenced the retrofit and/or construction phase of their Deep Retrofit Project.
  • Must be able to demonstrate ability to fund the project.

Building Eligibility

Buildings must be located within Toronto and be an Ontario Building Code Part 3 building (i.e. greater than 600 square metres or greater than three storeys). Eligible buildings include:

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

Participant Obligations

  • Enter into the Deep Retrofit Challenge Participant Agreement
  • Provide a calibrated pre- and post- retrofit 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 including opportunities to advance the design.
  • Agree that the City can make the details of the Deep Retrofit Project publicly available, including utility energy use and costs, designs, and project costs, to help drive uptake of similar retrofits. Deep Retrofit Projects will be featured in case studies and recognized for early transformative action.
  • Calculate and report on projected embodied carbon for major construction materials during the design phase (embodied carbon will not be factored into the performance incentive calculation) and prepare a plan to minimize embodied carbon during the retrofit.
  • Not 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.
  • Allow the City to make all decisions respecting the disposition of the emission reduction credits attributable to the Deep Retrofit Project.
  • Submit quarterly Progress Reports throughout the Project Term.
  • Grant the City of Toronto access to the Building to verify progress status, support creation of knowledge sharing products, or similar activities.
  • Provide a minimum of one year of pre-retrofit utility data for the Building (with preference given to additional provided data).
  • Provide a minimum of five years post-retrofit utility data for the Building.
  • Design and implement the retrofit using an approach that is replicable to similar building types across the city of Toronto and across similar climates within Canada.
  • Participate in City media event(s) and/or advertising campaigns promoting the Deep Retrofit Challenge and the Participant’s Deep Retrofit Project, including the building, technologies, etc.
  • Participate in the initial cohort of volunteers for the Net Zero Existing Buildings Strategy Actions 1 to 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)

The incentive limit for each selected deep retrofit project is:

$200 per square metre of gross floor area up to a maximum of $500,000 or 25% of Total Project Cost, whichever is less.

See Sections 4.6 (Claims and Incentive) and 4.7 (Emissions Performance Incentive Limit) of the Applicant Guide for more details.

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).

Upcoming Webinars:

There are no further webinars scheduled for the Deep Retrofit Challenge.

Previous Webinars:

In September 2022, the City hosted two webinars, covering the same content, for those interested in submitting an application for the Deep Retrofit Challenge.

September 9 Informational Webinar: 

September 21 Informational Webinar:

On May 26, the City held an ‘for the Deep Retrofit Challenge shortly after the grant program was announced. The information provided in the ‘Introductory Webinar’ includes some information that is now out of date, it is important to check the most recent webinar recordings, the Applicant Guide and the Questions and Answers document for the most  current information. Although some content in this webinar has been updated, we must keep this webinar posted for transparency purposes throughout the application intake period.

This final Q&A Deep Retrofit Challenge (DRC) is a summary of the questions received as part of the Deep Retrofit Challenge webinars and via the City’s Better Buildings Partnership e-mail (

The question and answer period for the Deep Retrofit Challenge closed on October 21, 2022.

Should you have any questions in regards to the program and receiving updates, please e-mail