Tech Specs

Definitions

U-VALUE

The U-Value is the heat flow rate through any construction.  The lower the U-value, the less heat transmitted.

U-Value is shown by Btu/hr/ft²/^oF

R-VALUE

The R-Value is the thermal resistance of a glazing system.  It is the reciprocal of the U-Value, which means the higher the R-Value, the less heat that is transmitted.

R Value is shown by hr x ft² x ^oF/Btu, or R=1/U

SHADING COEFFICIENT

Shading coefficient is the ratio of solar heat gain through a window to the solar heat gain through a single pane of 1/8” clear glass under the same conditions.  The smaller the number, the better the unit is at stopping solar heat from entering.

SOLAR HEAT GAIN COEFFICIENT(SHGC)

Solar heat gain coefficient is the fraction of solar radiation that enters a building as heat.  The smaller the number, the better the unit is at stopping solar heat from entering.

RELATIVE HEAT GAIN(RHG)

Relative heat gain is the total amount of heat gain through a glazing system at NFRC/ASHRAE specified summer conditions.

RHG is shown by Btu/hr/ft²

LIGHT TO SOLAR GAIN(LSG)

LSG is the ratio of visible light transmittance to solar heat gain.

SOLAR ENERGY TRANSMITTANCE

Solar energy transmittance is the percentage of UV, visible, and near infrared energy transmitted through the glass.

SOLAR ENERGY REFLECTANCE

Solar energy reflectance is the percentage of solar energy that is reflected from the glass surface.

VISIBLE LIGHT TRANSMITTANCE

Visible light transmittance is the percentage of light that is reflected from the glass surface relative to the C.I.E.(International Commission on Illumination) Standard Observer