Building Energy Benchmarking: Where to Start

A deadline that reshuffles the priorities

If you manage a commercial or institutional building over 5,000 m² in Greater Montreal, one date already concerns you: June 30, 2027. That is the day the first energy consumption disclosure becomes mandatory in Quebec — and it will require two years of monthly data. Which means the history you will have to submit in the summer of 2027 starts piling up now, in the summer of 2026.

Energy efficiency is often framed as a technician’s job. Building energy benchmarking flips that logic: before touching a single burner, you need to know where the property stands, and that is exactly what it measures. Far from an accounting chore, it is the decision tool that tells you whether your building consumes normally or wastes — and where to start. Here is the method.

What is building energy benchmarking, exactly?

Building energy benchmarking means measuring a property’s consumption, dividing it by its floor area, and comparing it to similar buildings. The first metric is energy use intensity (EUI): all the energy consumed in a year, divided by the gross floor area. In Canada it is expressed in gigajoules per square metre (GJ/m²). That single index blends natural gas and electricity onto one scale, which finally makes two very different buildings comparable.

The second metric is the ENERGY STAR score, from 1 to 100. A score of 50 is the median of the Canadian stock; a score of 75 or more makes the building eligible for certification. The reference tool for producing both numbers is ENERGY STAR Portfolio Manager, free and adapted to the Canadian context by Natural Resources Canada. As a rough marker, the median source EUI across all buildings in the system sits around 1.3 GJ/m², and about 1.5 GJ/m² for offices. These are orders of magnitude, not targets: your true reference is the peer group for your specific building type.

Why start now in Montreal?

The regulatory reason is blunt. The Building Environmental Performance Act introduces a mandatory disclosure overseen by the Ministère de l’Environnement. From June 30, 2027 it covers commercial and municipal buildings of 5,000 m² and up, residential buildings of 50 units and up, and government buildings over 100 m². In 2028 the threshold drops to 2,000 m² and 25 units. Because the first submission requires two years of monthly data and a professional validation is planned at regular intervals, waiting until 2027 to begin already puts you behind.

The financial reason is just as concrete. A serious benchmarking almost always exposes one or two abnormally hungry end uses — and that is exactly the prerequisite for tapping grant programs. Our guide to energy efficiency subsidies in Quebec funds precisely the kind of work a benchmark justifies with hard numbers. For a portfolio across Greater Montreal, it is the difference between investing blindly and investing where the payback is proven.

The method in six steps

Benchmarking does not require a consultant for a first pass. A methodical manager can do it in-house.

Tools you need

• Utility bills for the last 12 to 24 months (gas, electricity, any other source);
• the building’s gross floor area, exterior walls included;
• a free ENERGY STAR Portfolio Manager account;
• the building’s exact use type and occupancy hours.

1. Gather your utility bills

Collect all consumption, every source, over at least 12 months — aim for 24 to cover the disclosure requirement up front. A utility can often push consumption data straight into Portfolio Manager, which removes the manual entry.

2. Measure the gross floor area

This is the EUI denominator. An approximate area throws off the whole comparison: a 10% error on floor area shifts the score as much as a genuine efficiency gain. Take the gross measurement, exterior walls included.

3. Set up the building in Portfolio Manager

Open the account, enter the address (Canadian postal codes are recognized), the use type, the areas and the monthly data. The tool bakes in Canadian weather to normalize for climate.

4. Read the EUI and the score

Portfolio Manager computes EUI in GJ/m² and assigns a 1-to-100 score to eligible building types. The score is already weather-corrected: a harsh Montreal winter will not artificially penalize your number.

5. Compare against the peer group

The comparison draws on the Canadian CIEUS survey (Commercial and Institutional Energy Use Survey). Position your EUI against the median for your category. Above it, there is an opportunity; well above it, there is a problem.

6. Target and prioritize the gaps

Break consumption down by end use. Under Montreal’s climate — a long heating season measured in heating degree-days on an 18 °C base — heating is nearly always the top end use. A high EUI most often points to the boiler room: a mistuned burner, an outdated control sequence, an oversized appliance. That is where energy optimization delivers the best return per dollar.

How do you read your ENERGY STAR score?

The score reads at a glance, but it deserves some nuance.

A low score is not a verdict: it is a map. It tells you there is headroom, and step 6 tells you where to dig. Conversely, a good score has to be defended: without a track record, there is no proof a building holds its performance over time — and that is exactly what mandatory disclosure will verify.

A typical case: the boiler room dragging the score

Take a 1980s Montreal office building, some thirty thousand square feet, heated with natural gas. The manager believed it was “fine”: no complaints, bills paid without surprise. A first benchmark, however, lands it well above the median for its category — a high EUI, a score under 50.

The end-use breakdown points straight to the mechanical room: two original, oversized boilers short-cycling all through the shoulder seasons. Nothing broken, but a poor seasonal efficiency. Simply measuring it turned a vague hunch into a costed investment case — and made modernization work eligible for support that, without data, would have stayed at the bottom of the pile. It is the principle of good preventive maintenance scaled up to the whole building: you cannot fix what you have not measured.

The first number to go get this week

Building energy benchmarking is not a months-long project: it is a free account, two years of bills and one afternoon of data entry. The concrete move to make this week is simple — pull your bills and measure the gross floor area of your largest building. Before the month is out, you will have a first EUI and a score. From there, every maintenance or investment decision rests on numbers, not impressions. And the day disclosure becomes mandatory, you will not be scrambling for two years of data: you will already have it. Montréal Combustion works alongside Greater Montreal managers once the target is identified, turning a measured gap into real savings.