What is the minimum efficiency for a household gas tankless heater in Canada?

NRCan lists 0.86 UEF for units with a maximum flow rate below 6.4 L/min and 0.87 UEF for 6.4 L/min or more, for products manufactured on or after January 1, 2020.

What counts as a household unit?

NRCan defines it as a flow-activated gas or propane water heater with an input below 58.56 kW (200,000 Btu/h), a Vr of no more than 7.6 L (2 US gallons), designed to deliver water at no more than 82°C.

What about commercial tankless heaters?

Units outside the household definition, such as those above 58.56 kW input, are treated as commercial. NRCan lists a minimum thermal efficiency of 94% for those made on or after July 1, 2023.

Do provinces have their own rules?

Some do, for certain products. NRCan's page notes that some provinces regulate federally regulated products too, and links to a list. Check your province before relying on the federal floor alone.

Is this news or an explainer?

An explainer. We found no new federal change to these requirements when we checked in October 2026, so we've labelled it as a reference article rather than a news story.

Canada's Minimum Efficiency Rules for Gas Tankless Heaters

Canada sets minimum energy performance for gas tankless water heaters through the federal Energy Efficiency Regulations, 2016. Natural Resources Canada (NRCan) publishes plain-language summaries of the requirements, and those pages are a quick way to check what a model must meet before you quote it. This is a reference explainer, not a news report: we found no new federal change to these requirements when we checked in October 2026.

The household requirement

The short answer: 0.86 or 0.87 UEF, depending on maximum flow, for units made since 2020.

NRCan's household gas-fired instantaneous water heater page, last modified November 20, 2025, lists:

Maximum flow rate	Minimum UEF	Applies to units made
Less than 6.4 L/min	0.86	On or after January 1, 2020
6.4 L/min or more	0.87	On or after January 1, 2020

Products are tested to CAN/CSA-P.3-15. UEF, the uniform energy factor, is the efficiency rating homeowners see on spec sheets and rebate lists.

To fall into the household category, a unit must be flow-activated, run on natural gas or propane, have an input below 58.56 kW (200,000 Btu/h) and a Vr of no more than 7.6 L (2 US gallons), and be designed to deliver water no hotter than 82°C (180°F). Most residential wall-hung tankless heaters sold for a single home fit that description.

The commercial requirement

The short answer: 94% thermal efficiency for units made since July 2023.

Units that fall outside the household definition, for example those with an input above 58.56 kW, are covered by NRCan's commercial gas-fired instantaneous water heater page, modified January 6, 2026. It lists a minimum thermal efficiency of 94% for products manufactured on or after July 1, 2023, tested under the U.S. federal test procedure it cites. In practice, an efficiency that high points buyers toward condensing equipment.

Reporting and paperwork

The short answer: manufacturers and importers report each model to NRCan.

For household units, NRCan requires an energy efficiency report listing the product and brand name, model number, manufacturer, the certification body whose mark appears on the product, whether a mathematical model was used, the UEF and Vr, fuel type, input rate and maximum flow rate. Reports go through NRCan's online compliance database. The legal text sits in the Energy Efficiency Regulations, 2016, which the Justice Laws site showed as current to September 30, 2026 when we checked.

NRCan also notes that some provinces have their own energy efficiency rules for certain federally regulated products.

Terms worth knowing

The short answer: UEF, Vr and maximum flow rate are the three numbers on the NRCan page.

UEF (uniform energy factor): a single efficiency figure from a standard test, used for household units. Higher is better.
Vr: the rated storage volume. Household tankless units hold very little water, no more than 7.6 L.
Maximum flow rate: the most hot water the unit can deliver under test conditions, in litres per minute. It decides which UEF minimum applies.
Thermal efficiency: the measure used for commercial units instead of UEF.

Analysis: what the floor means for selling tankless

This section is TanklessNews.ca analysis, not NRCan guidance.

The legal floor is not a selling point. Every household tankless unit legally sold in Canada must meet 0.86 or 0.87 UEF, so "meets Canadian efficiency standards" tells a homeowner nothing. Compare the actual UEF of the models you quote instead.
Rebate bars can match the floor. SaskEnergy's August 2026 terms set 0.87 UEF for its $1,000 tankless rebate, the same figure as the federal floor for higher-flow units. The deciding factor there is SaskEnergy's eligible model list, not the number.
Flow rate drives sizing conversations. The 6.4 L/min split is a regulatory line, not a sizing rule, but it is a useful prompt to explain flow rate to customers. An undersized unit is one of the easier ways to end up with an unhappy customer.
Commercial is a different sale. At 94% minimum thermal efficiency, commercial buyers are choosing among condensing units. Marketing to property managers should focus on redundancy, maintenance and venting, not efficiency claims.
Ignore U.S. headlines unless they reach Canada. The U.S. withdrew its December 2024 gas tankless standard in 2025, as we reported in our DOE withdrawal story. Canada's numbers above did not change as a result.

We are a marketing and business consulting service, not a contractor or a compliance adviser; confirm requirements with NRCan. If you want product pages that explain efficiency accurately, see our local SEO service for tankless installers, or call, text or email.

What Canada's federal efficiency rules require of gas tankless water heaters