Absorbed
The amount of total solar energy that is absorbed in the glass. This heats up the glass, making it hotter to the touch, and reradiates a small amount of heat back into the room. The majority of absorbed energy is kept out of the room.
Visible Light
The portion of the solar spectrum containing visible light that we can see – it contains all the colours of the spectrum.
Transmitted
The amount of visible light that passes through the glass, into the building. This is how light or dark the film is, e.g., 35%.
Emissivity
The ability of the surface to reflect infrared energy. For window film, this means how much heat it will reradiate back into the room. Low E glass and films have low emissivity’s, which means they reflect a lot of heat back into a room, which is the desired effect in cold climates.
Glare Reduction
The reduction in visible light transmitted compared to clear un-filmed glass.
Infrared Rejection
The amount of infrared (IR) energy that is blocked by the film, either by reflecting or absorbing. This value is for the whole IR.
Luminous Efficacy
The ratio of visible light transmission to solar heat transmission for a window. A higher luminous efficacy means the film has a high heat rejection given its VLT.
Reflected Interior
The amount of visible light that is reflected off the interior surface of the window. This is seen when standing inside the building looking out. A higher reflectance value means the window looks more like a mirror from the inside.
Shading Coefficient
The ratio of heat passing through a filmed window to heat passing through clear un-filmed glass. A lower number means better heat rejection.
Solar Heat Gain Coefficient
Similar to the shading coefficient, except the value also takes into account energy that is reradiated back into the room from the glass heating up due to increased absorption. Again, a lower number means better heat rejection.
Total Solar Energy
All the energy in the solar spectrum that reaches us on the earth’s surface. This includes UVA and B, Visible light, and infrared energy.
Transmitted (Total Solar Energy)
The amount of total solar energy that passes through the glass, into the building.
Reflected
The amount of total solar energy that is reflected off of the glass and directed back outside. This energy does not come into the building.
U Factor (Winter)
Heat transfer due to the temperature differences outside and inside. Represents the amount of heat passing through 1 sq ft of glass in 1 hour for every 1 degree temperature difference between the outside and the inside. A lower value means less heat passes through – this is generally of interest for keeping heat inside the building in cold climates.
Ultraviolet Light Rejected
The amount of UV energy blocked by the film, either by reflecting or absorbing it. This energy does not enter the building.
