Cardinal Glass Technologies

Glass technologies at ClimateGuard offer innovative, top-of-the-line LoE glass technology from Cardinal Glass for optimal energy efficiency and superior thermal performance.

glass technologies

Cardinal Loe2-270 Glass

Cardinal LoĒ²-270® glass provides superior comfort during every season. This glass rejects the sun’s heat and UV rays to keep rooms cooler in the summer, while in the winter, heat is reflected back into the space to keep rooms warmer. While this glass type is similar to our LoĒ²-272® glass, the LoĒ²-270 has extra solar control and slightly less light transmittance. Regardless of your home’s location, ClimateGuard can help you choose windows that will provide the perfect amount of comfort, efficiency, and energy savings.


When Chicago’s summer heat hits, windows with Cardinal LoĒ²-270 glass reject the heat and UV rays that other windows welcome in. The patented coating provides superior solar control, visual clarity, and a reduction of window heat gain by 50% or more when compared to ordinary glass.


Chicago winters can be brutally cold and blustery. When temperatures drop, your windows directly influence how your rooms feel. Cardinal LoĒ²-270 windows for cold climates ensure that window surface temperatures stay warm, even during the coldest conditions.


The table below compares the temperatures of a variety of room-side glass types and winter temperatures.

  • Single-pane, clear
  • Double-pane, clear
  • Ordinary low-e (air fill)
  • LoĒ² – 270 (air fill)
  • LoĒ² – 270 (argon fill)
  • Outside temp -20°F (-30°C)
  • 0°F (-19°C)
  • 37°F (2°C)
  • 46°F (7°C)
  • 49°F (9°C)
  • 52°F (10°C)
  • Outside temp +20°F (-10°C)
  • 31°F (-3°C)
  • 51°F (9°C)
  • 57°F (13°C)
  • 58°F (14°C)
  • 60°F (15°C)
The Cardinal LoĒ²-270’s insulating capabilities make these windows ideal for homes and other buildings in cold climates. In addition to their thermal properties, these windows also contribute to proper humidity levels for a healthier living environment.
* 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 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
  • Single-pane, clear
  • Double-pane, clear
  • Ordinary low-e
  • LoĒ² – 270
  • Visible Light
  • 90%
  • 82%
  • 76%
  • 70%
  • Solar Heat Gain
  • 0.86
  • 0.78
  • 0.72
  • 0.37
  • Winter U-Factor
    (Air / Argon )
  • 1.04 / —
  • 0.48 / —
  • 0.34 / 0.30
  • 0.30 / 0.25
  • UV
  • 0.71
  • 0.58
  • 0.50
  • 0.14
  • Fading
  • 0.84
  • 0.75
  • 0.68
  • 0.53

Note: All values calculated using Window 6.3. 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 portion of energy transmitted in a spectral region from 300 to 600 nanometers. 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.

U-Factor – 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 LoĒ³-366 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.


Cardinal LoĒ²-270 glass technology protects and insulates against all weather conditions in most climates. Its unique coating blocks 86% of the sun’s harmful ultraviolet rays and 63% of the sun’s heat to keep rooms cool during the summer. No tints darken the light and personality of your space. In the wintertime, these windows reflect heat back into your home, contributing to energy savings and more comfortable living conditions. A great option for coastal buildings, these windows can even be purchased in hurricane-resistant laminated glass.