The part of the radiation which strikes a surface and is absorbed (gets caught in the material). Expressed as a percentage.
The temperature of the air.
A high gloss metal with unique reflective properties. One of the most common elements on Earth.
SI unit of light intensity (light intensity is the flow of light in a specific direction). Abbreviated cd or lm/sr (lumens per steriadian).
A measure of how much heat a material radiates compared with an ideal blackbody
Measured in joules (J). 1 joule of energy = enough energy to produce 1 W continuously for 1 s.
Total solar energy transmission through a window and sun blind together.
The sum of primary and secondary transmittance. The G-value indicates the total solar energy transmission through the window or sunblind. Indicated by a value between 0 and 1 or as a percentage. The higher the value, the more energy passes through.
Long-wave radiation. Wavelengths in the range 5000 - >25000 nm.
A window structure using two or three panes of glass. There is often gas (for example argon) between the panes and a low emissive layer in order to prevent the absorption of heat radiation (which prevents heat loss).
1000 Wh = 3 600 000 Joules. See Watt-hour.
SI unit of luminous flux (light energy per unit of time). Abbreviated lm.
Light intensity (candela) per square meter. Measured in cd/m².
Wavelengths in the range 5000->25000 nm. Also known as heat radiation.
SI unit of illuminance, lighting (luminous flux per lit area). Abbreviated lx or lm/m².
The proportion of open spaces in the product. A percentage to describe the amount of direct insolation allowed through.
The perceived temperature. Approximately the average of air temperature and radiation temperature.
All materials emit radiation in the form of heat (or cold).
The part of the radiation which strikes a surface and is reflected back. Expressed as a percentage.
The heat transfer supplied to the room due to absorbed solar radiation from e.g. windows and sunblinds.
SF - Solar factor
Indicates the g-value for sun blinds. This figure is worked out by dividing gtot by gwindow = gsolar protection (this value can only be used in the case in question).
Wavelengths in the range 320-2500 nm. See Solar radiation
Solar protection glass
Dark glass which screens out parts of the insolation. The aim is to screen out UV and IR, but this cannot be achieved without also screening out parts of the visible light.
Short-wave electromagnetic radiation consisting of UV, visible light and IR. Wavelengths in the range 320-2500 nm.
ST - Solar energy transmission
Normally, a person experiences thermal comfort when the operative temperature is between 20 and 24 degrees.
The part of the radiation which strikes a surface and is transmitted (passes through). Expressed as a percentage.
Primary transmittance of solar radiation through a window or sunblind, for example; i.e. direct insolation. Indicated by a value between 0 and 1 or as a percentage of the total solar radiation.
TST – Total solar energy transmission
Percentage of Tsol that consists of visible light.
Heat transfer coefficient, i.e. describes the insulating properties of the material, and is specified in W/m2 K. The lower the U-value, the better the insulation.
SI unit of output (energy per second). Abbreviated W.
Wh - Watt-hour
A unit of energy which is defined as the output of one Watt over 1 hour, and so 3600 watt-seconds = 3600 Joules.
Part of solar radiation with wavelengths in the range 380-780 nm. Also known as daylight.
When a person does not experience disruptive glare or reflections caused by a light source such as the sun.