What should I know about windows, doors and skylights?

In addition to what is described about windows, doors and skylights section of the Grant Table, there are a number of important considerations.

 

As proof of ENERGY STAR qualification, homeowners must provide the ENERGY STAR label or a copy of an invoice indicating the brand/product name, and the NRCan model reference number or the manufacturer's model code, as well as the climate zone for which the windows, doors or skylights are qualified.  If possible, DO NOT remove ENERGY STAR stickers before your post-retrofit evaluation or, if they must be removed, keep them as proof.

 

For purposes of the grant, NRCan defines one unit of window as one rough opening in the wall. A large window consisting of multiple panels of glass is counted as one opening in the wall, regardless of how large the window is, or how many windows is required to fill the rough opening. For example, NRCan considers a typical bay or bow window as one rough opening or one window which would therefore qualify for a single window grant.

Windows in unconditioned spaces such as unheated attics, garages and sun porches are not eligible for a grant.

 

Technical specifications for ENERGY STAR qualified windows, doors and skylights (fenestration products) became more stringent as of October 1, 2010, and there is now mandatory labelling of all such products in Canada.  (See table below for requirements).

 

A window may consist of one or more factory-assembled individual units: multiple units may be connected together at the factory or at the site of installation, and each unit in the assembly must be ENERGY STAR qualified. The new window may be installed within the existing frame of the old window, but you cannot replace only the glass or sash. An ENERGY STAR door system will consist of a door “slab” (with or without glazing) and optional sidelites or transoms fully assembled (“prehung”) within a new frame. Sidelites and transoms are rated separately and must also be ENERGY STAR qualified if included in the door system for one rough opening. Replacement of door slabs without a frame and individual sidelights or transoms are not eligible. Skylights must be factory assembled, as site assembled skylights do not qualify for a grant. Glass or sash replacement only does not qualify for a grant.

ENERGY STAR^®Qualifications for Fenestration Products

For ENERGY STAR, windows and doors are qualified for their energy efficiency by either a U-value or Energy Rating (ER) for each of the four Canadian zones. Skylights are qualified by their U-value only. The energy efficiency values were developed primarily for low-rise residential dwellings (three floors or less).

The following tables show the levels for each climate zone in Canada. The ratings given in the tables are for the entire product.  Energy efficiency ratings for the glass portion only, often called "centre-of-glass", ratings usually make the product appear more energy efficient than it really is.

ENERGY STAR Requirements for Windows and Doors
Products may comply based on either their U-value and R-value or their Energy Rating

ENERGY STAR Requirements for Skylights

Skylights* (Effective October 1, 2010)
Zone	Heating Degree-Day Range	Maximum U-Factor W/m²•K (Btu/h•ft.²•°F)
A	<= 3500	2.80 (0.50)
B	> 3500 to <= 5500	2.60 (0.46)
C	> 5500 to <= 8000	2.40 (0.42)
D	> 8000	2.20 (0.39)

*includes Tubular Skylights

U-Factor Conversion to R-Value

Windows, doors and skylights are not normally assigned an R-value when tested. To help you better understand their insulating performance, sample U-factors in both metric and imperial units have been converted to R-values in the table below. Because Energy Rating values are derived from a formula that uses both U-factor and solar heat gain, there is no method to directly convert the Energy Rating value to R-value.

U-Factor Conversion to R-Value
U-Factor W/m²•K	U-Factor Btu/h•ft.²•°F	R-Value ft.²•h•°F/Btu
3.40	0.60	1.7
3.20	0.56	1.8
3.00	0.53	1.9
2.80	0.50	2.0
2.60	0.46	2.2
2.40	0.42	2.4
2.20	0.39	2.6
2.00	0.35	2.9
1.80	0.32	3.2
1.60	0.28	3.6
1.40	0.25	4.0
1.20	0.21	4.8
1.00	0.18	5.6
0.80	0.14	7.1
0.60	0.11	9.1

Airtightness and Other Ratings

All windows and sliding glass doors must be rated for their airtightness, watertightness, wind load strength, resistance to forced entry, insect screen strength (windows only) and ease of operation (sliding glass doors only) when they are installed in new homes or buildings. Provincial/territorial and local building codes require different airtightness, watertightness and window load strength categories depending on the climatic conditions.

All ENERGY STAR qualified sliding glass doors and operable windows must have at least an A2 for airtightness. Picture windows must receive a "Fixed" rating. The following table shows the range for each product type.

Airtightness – Windows and Sliding Glass Doors
Type	Least Airtight	Most Airtight
Most operable windows	A1	A3
Single-hung windows*	A1/Fixed	A3/Fixed
Single sliding windows*	A1/Fixed	A3/Fixed
Non-operable (fixed) casement windows	A1	A3
Picture windows	Fixed (pass/fail rating)
Sliding glass doors	A1	A3

*Operable and non-operable sashes may be tested and rated separately for single-hung and single sliding windows.

There are no minimum requirements for ENERGY STAR for the other categories. The following table shows the ranges for each product type.

Other Categories – Windows
Type	Least Airtight	Most Airtight
Watertightness	B1	B7
Wind load strength	C1	C5
Insect screen strength*	S1	S2
Resistance to forced entry	F10 or F1	F20 or F2

*This test measures only how well the screen mesh stays fastened to the screen mesh frame, not how well the insect screen stays fastened to the window frame. Most insect screens are designed to be easily removable from the window to allow for egress in case of an emergency. An S1 rating is normally adequate for residential applications.

Other Categories – Sliding Glass Doors
Type	Least Airtight	Most Airtight
Watertightness	B1	B4
Wind load strength	C1	C3
Ease of operation	E1	E3
Resistance to forced entry	F1	F2

NOTE:  Insect screen strength, resistance to forced entry and ease of operation ratings are not available in the ENERGY STAR qualified model listings.

The ENERGY STAR name and symbol are administered and promoted in Canada by Natural Resources Canada and are registered in Canada by the United States Environmental Protection Agency.