The "40% reduction" claim gets repeated a lot, and for good reason. In Ontario, one of the most widely cited evaluations of submetering is a Navigant Consulting report prepared for Enercare, titled "Evaluation of the Impact of Sub-Metering on Multi-Residential Electricity Consumption and the Potential Economic and Environmental Impact on Ontario" (January 8, 2016).
The report analyzes data provided by Enercare for thousands of apartment units over multiple years. It estimates that once units switched from bulk billing to submetering, average monthly suite electricity use dropped materially. The report describes an average first-year reduction of 139 kWh per unit per month, and frames that as roughly a 40% reduction in the first year, with discussion of persistence over subsequent years.
The important takeaway is not that every building will see the same percentage. It is that suite-level billing accountability drives real conservation at scale.
Submetering changes three things at once: the cost becomes personal, the feedback loop becomes real, and effort becomes worth it. When usage is bundled into rent or common expenses, the marginal cost of waste feels invisible.
When you hear "40% reduction," ask: 40% of what? In the Navigant analysis, the reduction is framed relative to suite consumption. It is not automatically a 40% reduction of the building's total electricity use, because total building use includes common areas, central mechanical systems, and building equipment loads.
Practical implication: if suites represent a large portion of total building electricity, the building-wide impact can still be meaningful. If common areas dominate, you still get billing fairness and operating expense relief, but total kWh reductions may look smaller without additional efficiency work.
Use wording like: "A landmark Ontario evaluation found average first-year reductions around 40% in suite electricity use after submetering, with savings persisting over time." Avoid wording like: "You will cut your building bill by 40%."