By-law concerning GHG emission disclosures and ratings of large buildings

Last updated March 5, 2026
Reading time: 3 min
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The city adopted the By-law concerning GHG emission disclosures and ratings of large buildings on September 27, 2021 with the objective of becoming carbon-neutral by 2050. The by-law fulfills one of the objectives set out in the Montréal Climate Plan.

By-law 21-042 requires owners of large buildings with an area of 2,000 square metres (21,528 square feet) or greater OR buildings with 25 dwellings or more to report GHG emissions generated by their building’s energy consumption. The city aims to gather more information about these emissions; compare them, in particular by assigning a rating; and develop measures to reduce them.

Obligations

Owners of large buildings must submit monthly energy consumption data for the entire building to the city by June 30 of each year. The data must cover the period from January 1 to December 31 of the previous year.

This information collected will let the city draw a complete portrait of greenhouse gas (GHG) emissions from large buildings in Montréal. This portrait will be used to develop programs to improve buildings’ energy performance.

Buildings subject to the by-law

The by-law is intended for owners of existing buildings in the commercial and institutional sectors, and large multi-unit residential buildings of 2,000 m2 or more or of 25 dwelling units or more.

Exceptions 

  • Buildings whose predominant use on the property assessment roll includes an industry
  • Buildings occupied in whole or in part by a company, facility or establishment subject to section 6.1 of the Regulation respecting the mandatory reporting of certain emissions of contaminants into the air (CQLR, chapter Q-2, r. 15).
See subject buildings

The fact that a building appears or does not appear on this list cannot be interpreted as exempting anyone from compliance with by-law 21-042 or any other applicable municipal by-law. The list of buildings subject to this requirement has been compiled based on preliminary data and is subject to change. Its only purpose is to serve as a reference for building owners.

For questions or changes to the list, please e-mail [email protected].

Steps

Read the Detailed Guide (in French)

1 - Identify your building: Find the building ID under “Identifiant standard Montréal ‐ Divulgation ID” (standard ID type “Montréal - Disclosure Building ID#” ) in the list of buildings subject to the by-law (in French).

2- Go to the ENERGY STAR Portfolio Manager® online portal.

  • Create an account and add your buildings.
  • Enter the information required under the by-law (address, type of building use, floor area by type of use, building ID and billing data from your energy suppliers, etc.).
  • Activate automatic transfer of energy consumption data from Hydro-Québec and Énergir.
  • Check your data with the ESPM Data Quality Checker.
  •  Transfer your data to Montréal:

3 - E-mail the city’s disclosure rating department to get the form provided by the city.

Benefits

The disclosure and rating system for large buildings, and the future integration of performance thresholds as foreseen in the Climate Plan 2020-2030, will have important benefits for building owners and Montréal residents.

This system will:

  • Track GHG emissions from buildings and compare them to similar buildings in Montréal.
  • Target measures to improve building performance and assess their impact.
  • Reduce the costs and GHG emissions generated by energy consumption.
  • Show that Montréal building owners are leaders in energy transition, a major competitive advantage in the real estate sector.

Support for owners

Ville de Montréal

Guidance

Webinars

Understanding the by-law:

Using the ESPM:

  • Webinar about using the ENERGY STAR Portfolio Manager (in French)
  • Visual support for the webinar (in French)
  • Video about automating energy data transfer (in French)

Hydro-Québec

Énergir

Natural Resources Canada (NRCan)

Any questions?

E-mail: [email protected].

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