|
Window Energy
Performance
Total unit "U" values*
Data supplied by Manufacturers
For average size windows with insulated, dual pane glass & warm
edge spacer
| Atrium |
w/Clear Glass |
w/Low E2 |
w/Low E2
& Argon |
|
|
| 200 Single Hung |
.50 |
N/A
|
.33 |
|
|
| 200 XO Slider |
.50 |
N/A |
.33 |
|
|
| 7800 Double Hung |
.48 |
N/A |
.31 |
|
|
| 7800 XX Slider |
.48 |
N/A |
.31 |
|
|
| 7800 Casement |
.46 |
N/A |
.30 |
|
|
| CertainTeed |
|
|
|
|
|
| Somerton Single Hung |
.54 |
.42 |
.35 |
|
|
| Somerton XO Slider |
.53 |
.41 |
.34 |
|
|
| Bryn Mawr II Double Hung |
.50 |
.38 |
.33 |
|
|
| Bryn Mawr II XX Slider |
.50 |
.37 |
.32 |
|
|
| Bryn Mawr II Casement |
.50 |
.38 |
.33 |
|
|
| Superior |
|
|
|
|
|
| Deluxe Single Hung |
.49 |
.35 |
N/A |
|
|
| Deluxe XO Slider |
.49 |
.35 |
N/A |
|
|
| Ultima Single Hung |
.47 |
.35 |
N/A |
|
|
| Ultima Double Hung |
.48 |
.36 |
N/A |
|
|
| Ultima XO Slider |
.47 |
.34 |
N/A |
|
|
| Ultima Casement |
.42 |
.32 |
N/A |
|
|
| Magic |
|
|
|
|
|
| Single Hung (Thermosonic) |
.50 |
.42 |
.33 |
|
|
| XO Slider (Thermosonic) |
.50 |
.41 |
.33 |
|
|
| Double Hung (Thermosonic) |
.48 |
.39 |
.31 |
|
|
| XX Slider |
.48 |
.38 |
.31 |
|
|
| Casement |
.45 |
.37 |
.30 |
|
|
| |
|
|
|
|
|
* "U" value:
The rate of heat flow through a window or door system; the lower the
value, the better the insulating quality. U-value can be compared to
R-value by dividing 1 by the U-value. I.E. A U-value of .5 equals an
R-value of 2.
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U-value and R-value
Comparisons
| |
Typical Window Construction |
U-value |
R-value |
| 1. |
Aluminum Frame
Single Pane
Clear Glass |
1.3 |
.76 |
| 2. |
Aluminum Frame
Dual Pane, 1/2" Air Space
Clear Glass |
.75 |
1.3 |
| 3. |
Vinyl Frame
Dual Pane, 1/2" Air Space
Clear Glass |
.52 |
1.9 |
| 4. |
Vinyl Frame
Dual Pane, 1/2" Air Space
Low E2 Glass with
Argon gas fill |
.30 |
3.3 |
| 5. |
Vinyl Frame
Triple Pane
Double Low E2
With argon gas fill |
.13 |
7.6 |
| 6. |
Vinyl Frame
Triple Pane
Double Low E2
With krypton gas fill |
.10 |
10.0 |
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Typical Glass
Performance
| |
Clear Single Pane |
Clear Dual Pane |
Low E2
Dual Pane |
Low E2
w/ Argon Dual Pane |
| U-value |
1.29 |
.46 |
.34 |
.28 |
| R-value |
.77 |
2.2 |
2.9 |
3.6 |
| Visible Light Transmittance |
90% |
82% |
72% |
72% |
| Ultra Violet Blockage |
27% |
42% |
84% |
84% |
| Shading Coefficient |
1.00 |
.87 |
.47 |
.47 |
| Solar Heat Gain Coefficient |
.80 |
.72 |
.33 |
.33 |
U-value - The amount of heat
transmitted by the glass, the lower the better.
R-value - Designates the glass resistance to heat flow, the
higher the better.
Visible Light Transmittance - The percentage of visible
light transmitted through the glass.
Ultraviolet Blockage - The percentage of harmful &
damaging UV rays blocked from transmitting through the glass, the
higher the blockage percentage, the better.
Shading Coefficient - The ratio of solar heat gain through
a particular type of glazing compared to the solar heat gain
allowed through a single lite of 1/8" clear glass. The lower
the number, the better.
Solar Heat Gain Coefficient - The fraction of incident
solar radiation entering a home through the windows. The lower the
number, the better the window is at preventing solar heat gain.
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