Haze indicates the percentage of the perpendicular incoming light that deflects from the straight line at an angle of more than 2.5°. For example, if 60% of the direct light is deflected, this is expressed as a haze percentage of 60%.

Diffusion of light is indicated by a haze factor. The higher the haze, the greater the diffusion. Blank float glass does not diffuse the light and therefore has a haze factor of 0%. In general, the higher the haze value, the lower the hemispheric light transmission (hem. LT). This means that in the case of a low haze the (hem.) LT is higher than for a high haze. The correct combination of haze value and (hem) LT depends on the crop, the climate and the growing strategy.