Glass Performance Chart
| Code | Description | U-Value | R-Value | Solar Heat Gain | Visible Light Transmittance | |
|---|---|---|---|---|---|---|
| Clear | Dual | Dual pane, clear glass, no coatings | 0.480 | R-Value">2.084 | 0.760 | 81% |
| Clear | Tri | Triple pane, clear glass, no coatings | 0.310 | R-Value">3.226 | 0.685 | 74% |
| LOW-E | HS1-C180 | Dual pane, one Low-E coating, Argon | 0.260 | R-Value">3.846 | 0.685 | 79% |
| LOW-E | HS2-C180 | Triple pane, one Low-E coating, Argon | 0.184 | R-Value">5.433 | 0.615 | 73% |
| LOW-E | HS3-C180 | Triple pane, two Low-E coatings, Argon | 0.133 | R-Value">7.521 | 0.560 | 70% |
| SUNSTOP | HS4-C270 | Dual pane, one SunStop coating, Argon | 0.248 | R-Value">4.033 | 0.367 | 70% |
| SUNSTOP | HS5-C270 | Triple pane, one SunStop coating, Argon | 0.186 | R-Value">5.377 | 0.338 | 63 |
| SUNSTOP | HS6-C270 | Triple pane, two SunStop coating, Argon | 0.124 | R-Value">8.065 | 0.310 | 54 |
| SYSTEM V | HS1V-C180/i89 | Dual pane, two Low-E coatings, Argon | 0.209 | R-Value">4.783 | 0.623 | 77 |
| SYSTEM V | HS4V-C270/i89 | Dual pane, one Low-E & one SunStop coating, Argon | 0.200 | R-Value">4.998 | 0.361 | 69 |
Notes
Values are in METRIC. All performance for C.O.G. (centre of glass) ratings are based on Vision v4.0 simulations. All C.O.G U- and R-values are based on ASHREA Winter Conditions. Framing, cladding, frame type and other items will affect the overall thermal values of a complete window.
U Value: the total heat transfer out of a window (Btu/hr-sq ft-F or W/sq m- C). The lower the number the better the glass.
R-Value: the amount of heat retained by the window. The higher the number the better the glass.
Solar Heat Gain Coefficient: the amount of solar radiation which enters the house through radiation. This is expressed as a dimensionless number between 0 and 1. It represents the heat gain through 3mm clear glass.
Visible Light Transmittance: measures how much of the visible light is entering the building through the glass. 1.0 would mean all of the light was getting through and 0 would mean none of it was getting through. Our atmosphere naturally filters out 5% of the visible light. Clear glass with no coatings lets in approx. 90% of visible light.