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Ontario looking at 1.6 U-factor maximum for all windows sold in province

September 30, 2019  By Patrick Flannery

The Ontario government is seeking industry input on a proposal to update regulations to require any windows sold in the province to meet a standard of 1.6 U-factor or 25 energy rating. The regulation would apply to products manufactured in 2022 and later. The Ontario building code presently requires a 1.6 U-factor or better for windows installed into new construction and a 2.0 U-factor/17 ER for any windows sold. Window manufacturers are invited to comment on the proposal here. Deadline for comments is Oct. 30.

Full text of the announcement from the Ministry of Energy, Northern Development and Mines:

I am writing to seek your feedback and assistance which would help inform the Ministry of Energy, Northern Development and Mines (Ministry) in its assessment of potential cost impacts associated with a potential proposal to update the efficiency standard for residential windows under Ontario’s Energy and Water Efficiency – Appliances and Products regulation (O.Reg. 509/18 made under theElectricity Act, 1998).

Window efficiency standards are an important source of potential energy savings in Ontario: inefficient windows can account for up to 30% of heat loss in the home. That is why Ontario introduced efficiency standards for windows in the province back in 2012.O.Reg. 509/18 requires that windows for low-rise residential buildings sold in the province have either a maximum U-factor of 2.0 W/m2°C or a minimum energy rating of 17 (O.Reg. 509/18, Schedule 8).


Since then, British Columbia has updated its window efficiency standards to a maximum U-factor of 1.8, and is now proposing to move to a U-factor of 1.61 beginning in 2022. The maximum U-factor prescribed under the Ontario Building Code for windows in new low-rise residential buildings is 1.6. To keep pace with other jurisdictions and drive further energy savings through efficiency, the Ministry is now considering potential updates to its window efficiency standards that would set the requirement to a U-factor of 1.6/energy rating of 25 for products manufactured in 2022 and later to further align with the Ontario Building Code minimum and British Columbia’s proposal.

I am writing to seek your assistance in assessing any potential cost impacts of this proposed change under consideration. Please review and complete the attached survey by email, or fill it out onlinehere. Your input will be an important part of the Ministry’s assessment. Should the Ministry proceed with a regulatory proposal for this change, the proposal will be posted along with proposed changes for nine other (unrelated) productson theEnvironmental Registry of Ontario. Manufacturers and other stakeholders will have the opportunity to submit more detailed comments on the proposal at that time.

Thank you in advance for your participation in this survey. Feedback is requested no later thanOctober 30, 2019. The survey can be completedonlineor using the attacheddocument. Completed surveys, as well as any questions regarding the survey, can be sent by email to feedback.to.cee@ontario.ca. Information collected by the Ministry shall be kept confidential, subject to any disclosure that may be required under theFreedom of Information and Protection of Privacy Actor other applicable law. Additionally, the Ministry may publish aggregated results of the survey responses provided. In doing so, the Ministry shall ensure that such information is appropriately anonymized and aggregated so that it is not attributable to the specific stakeholder.

Andrew Howse
Senior Advisor, Energy Efficiency Standards
Ontario Ministry of Energy, Northern Development and Mines

[Thanks to Harry Schroeder at Manitoba Hydro for correcting the original headline’s reference to U-factor “minimum.” While 1.6 U-factor is the performance minimum (ie the window must achieve this or better), U-factors are better the lower they get. Thus the proposal is setting a maximum U-factor as its minimum requirement. Now that you’re all as confused as me, let’s go out and educate the public. – Ed.]

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