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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.

Note: Effective October 1, 2010 the requirements are changing. The tables indicate the current requirements followed by the new requirements.

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

Zone Maximum U-Values
and Minimum R-Values
Minimum Energy Rating (ER) Values
(Maximum U-Value 2.00 W/m2•K)
U-Value
(W/m2•K)
U-Value
(Btu/h•ft.2°F)
R-Value
(ft.2•h•°F/Btu)
  Most Windows and
All Doors
(includes fixed
casement
style windows)
Picture
Windows
Only
1998 2004* 1998 2004*
A 2.00 0.35 2.9 or –16 17 –6 27
B 1.80 0.32 3.2 or –12 21 –2 31
C 1.60 0.28 3.6 or –8 25 +2 35
D 1.40 0.25 4.0 or –5 29 +5 39

*The methodology used to calculate Energy Ratings, as defined by the Canadian Standards Association, was recently changed. Under the new 2004 standard, all windows and doors have positive ER numbers.


Windows (Effective October 1, 2010)
Zone Heating
Degree-Day
Range
Compliance Paths
Energy Rating (ER) or U-Factor
Minimum ER (unitless)
Maximum U-Factor 2.00
W/m²•K
(0.35 Btu/h•ft.²•°F)
  Maximum
U-Factor
W/m²•K
(Btu/h•ft.²•°F)
Minimum
ER
(unitless)
A <= 3500 21 or 1.80 (0.32) 13
B > 3500 to <= 5500 25 or 1.60 (0.28) 17
C > 5500 to <= 8000 29 or 1.40 (0.25) 21
D > 8000 34 or 1.20 (0.21) 25

Doors (Effective October 1, 2010)
Zone Heating
Degree-Day
Range
Compliance Paths
Energy Rating (ER) or U-Factor
Minimum ER (unitless)
Maximum U-Factor 2.00
W/m²•K
(0.35 Btu/h•ft.²•°F)
  Maximum
U-Factor
W/m²•K
(Btu/h•ft.²•°F)
Minimum
ER
(unitless)
A <= 3500 21 or 1.80 (0.32) N/A
B > 3500 to <= 5500 25 or 1.60 (0.28) N/A
C > 5500 to <= 8000 29 or 1.40 (0.25) N/A
D > 8000 34 or 1.20 (0.21) N/A

ENERGY STAR Requirements for Skylights

Zone Maximum U-Value
(W/m2•K)
Maximum U-Value
(Btu/h•ft.2•°F)
Minimum R-Value
(ft.2h•°F/Btu)
A 3.10 0.54 1.8
B 2.80 0.50 2.0
C 2.60 0.46 2.2
D 2.38 0.42 2.4

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 Categories – 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

Test Lowest Category Highest Category
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 removeable 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

Test Lowest Category Highest Category
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.