Comfort in all types of weather.

Who says you can’t do anything about the weather? Cardinal's LoĒ² coated glass delivers year-round comfort in all types of weather. In summer, it rejects the sun’s heat and damaging UV rays. In winter, it reflects heat back into the room.

Cardinal LoĒ² glass includes two variations, LoĒ²-272 and LoĒ²-270. LoĒ²-272 offers a little more light transmittance, while LoĒ²-270 gives a little more solar control.

Regardless of where your home is located, choosing windows that provide you with the highest level of comfort and energy savings year-round is extremely important. And choosing the right glass for your windows is the most important factor in that decision. Go beyond ordinary low-e glass. Let LoĒ² glass help you handle the weather – any weather.

Hot sun? Cool windows.

When the temperature is heading to the top of the thermometer, ordinary window glass simply welcomes in the heat. Cardinal LoĒ², however, has been specially formulated to reject the sun’s heat and damaging rays and keep your home cool and comfortable.
The patented LoĒ² coating provides high performance solar control and visual clarity. The end result of all this engineering is that Cardinal LoĒ² provides the ultimate in comfort because it reduces window heat gain by 50% or more when compared to ordinary glass.

Frigid outside, cozy inside.

During cold weather, the insulating effect of your windows has a direct impact on how your rooms feel. Typically, 75% of the exposed surface of a window is glass, and the temperature of the room-side of the glass directly affects the air temperature in the room. The better insulated the window glass, the warmer your room will be.
In fact, the Efficient Windows Collaborative ( suggests that when glass surface temperatures fall below 52°F, there is a risk of thermal discomfort. To maintain the best comfort during the winter, select a glass product that produces surface temperatures that will stay above this point during the coldest outdoor conditions.

Inside glass and outside temperatures.

The table below compares the room-side center of glass temperatures of different glass types against two different winter conditions.
IG Type
and Coating
Single-pane, Clear
Double-pane, Clear
Ordinary low-e
LoĒ²-272 / LoĒ²-270 (air fill)
LoĒ²-272 / LoĒ²-270 (argon fill)
    Inside Glass Temperature: °F°C
  • 37°
  • 46°
  • 49°
  • 52°
  • -19°
  • 10°
  • 31°
  • 51°
  • 57°
  • 58°
  • 60°
  • -3°
  • 13°
  • 14°
  • 15°
The superior insulating capability of Cardinal LoĒ² glass is a key factor in the construction of comfortable windows for cold climates. The dramatic comfort improvement from windows with warm glass surfaces also means the relative humidity of the indoor air can be controlled and maintained properly. Proper humidity levels (not too much, not too little) will improve comfort and promote a healthier living environment.

Glass so smart, it controls your comfort.

Although windows provide beautiful views and wonderful natural light, they can also account for up to 50% of the heating and cooling energy consumed in a home. In the summer Cardinal LoĒ² keeps your home cool and comfortable by rejecting the sun’s heat and damaging rays. In the winter it helps your home stay warm and cozy by blocking heat loss to the cold weather outside. In short, it can save energy year around.
Thermostat settings are the largest variable in establishing the heating and cooling energy savings potential with window replacements. If you tolerate the discomfort from your current windows and don’t change thermostat settings with the weather, consider the savings suggested from the “Fixed Thermostat” column. If on the other hand you frequently adjust the thermostat, add space heaters to compensate for cold rooms, or close drapes/blinds to block the sun consider the additional savings suggested in the “Equal Comfort” column.

Heat/Cool portion of your energy bill:DOE estimates that in 2005 the average house spent $2,003 on utilities and that 43% of this total ($886) is for heating and cooling energy. (

Savings values are average of multiple locations within climate zone.

“Average” house as described in the Buildings Data Book at The model house is described as a mid-1970’s single-story dwelling with natural gas furnace, central air-conditioning, adequate insulation, and double-pane windows.

Window orientation set as uniformly distributed on all sides to represent a neighborhood average and the total window area set to 15% of the floor area.

Interior shading devices are presumed to be closed 50% of the time throughout the year.

“Fixed Thermostat” conditions are 70°F for heating and 75°F for cooling.

“Equal Comfort” thermostat settings determined using window thermal comfort research from the University of California at Berkeley ( The existing double-pane windows used heat/cool thermostat setpoints of 72°F/74°F to match the comfort of LoĒ²-270 glass at 70°F/78°F.

House heat/cool energy simulations used the Resfen program from Lawrence Berkeley National Lab (

Glass Performance

IG Type
and Coating
Single-pane, Clear
Double-pane, Clear
Ordinary low-e
    Visible light
  • 90%
  • 82%
  • 76%
  • 72%
  • 70%
  • 8%
  • 15%
  • 17%
  • 11%
  • 12%
  • 8%
  • 15%
  • 17%
  • 12%
  • 13%
    Fade Transmission
  • 71%
  • 58%
  • 50%
  • 16%
  • 14%
  • 84%
  • 75%
  • 68%
  • 55%
  • 53%
  • 0.86
  • 0.78
  • 0.72
  • 0.41
  • 0.37
  • 5.91
  • 2.73
  • 1.93
  • 1.70
  • 1.70
  • 1.04
  • 0.48
  • 0.34
  • 0.30
  • 0.30
  • --
  • --
  • 1.70
  • 1.42
  • 1.42
  • --
  • --
  • 0.30
  • 0.25
  • 0.25
GENERAL NOTES: (1) Data was calculated using the LBNL Window computer program per NFRC environmental conditions. (2) 90% argon/10% air fill is used for IG’s with LoE coated glass, otherwise 100% air fill is used for uncoated units.

All values calculated using Window 7.4. (See and for more information on glass optical data and the Window 7.4 program.) Emittance of ordinary (pyrolitic) low-E is 0.16.

Solar Heat Gain Coefficient – (SHGC):
The amount of solar radiation that enters a building as heat. The lower the number, the better the glazing is at preventing solar gain.

Fading Transmission:
The UV Transmittance is determined as an average for wavelengths 300 -380 nm. UV Damage Weighted Transmittance (Tdw) is the weighted average for wavelengths 300 – 780 nm (based on CIE 89/3). This region includes all of the ultraviolet energy and part of the visible spectrum, and will give the best representation of relative fading rates. The lower the number, the better the glass is for reducing fading potential of carpets and interior furnishings.

This represents the heat flow rate through a window expressed in BTU/hr·ft²·°F, using winter night weather conditions of 0°F outside and 70°F inside. The smaller the number, the better the window system is at reducing heat loss.

Cardinal actively supports and participates in the National Fenestration Rating Council (NFRC). Windows with LoĒ² that are rated and certified by the NFRC can comply with Energy Star requirements in all regions of the country. Northern zone will likely require the addition of LoĒ-i89 on the 4th surface to comply with U-Factor requirements.

(See for more information on the Energy Star windows program.)

The difference is clear.

Cardinal LoĒ² glass is ideal for all weather conditions in most climates. In summer, its patented coating blocks 86% of the sun’s harmful ultraviolet rays and 63% of the sun’s heat. It even outperforms the tinted glass often used in warm climates. You can see out and the light shines in, with no heavy bronze or smoke colored tints to darken the personality of your home. In winter, it reflects heat back into rooms.

LoĒ² glass can also be purchased in hurricane-resistant laminated glass and in a variety of shapes and sizes.

To learn more about LoĒ² and other Cardinal glass products, ask your window manufacturer, contractor or architect.

More info:

Additional Resources for This Product

5:46 Coated Glass Technology Tour
LoĒ² Glass
PDF Brochure