They are suitable for installation in rooms ranging in height from approx. 2.60 m to 4.00 m. They offer high induction, resulting in swift reduction of the supply air temperature differential and the air discharge velocity. The recommended volume flow range is 25 to l/s · m, while the permissible supply air temperature differential stands at ±10 K. The stable discharge behaviour of slot diffusers makes them suitable for use in systems with constant or variable volume flow. The air discharge direction can be adapted as necessary to the desired room conditions.

Slot diffusers are generally supplied with rear-mounted plenum box, whereby the air duct system is connected via the side-mounted round spigot.

Swirling, horizontal discharge of the supply air at a high induction rate guarantees swift temperature equalisation and fast reduction of the flow velocity. Up to 30 room air changes per hour are attainable at supply air temperatures between +10K and -10K. In order to stabilize the supply air flow, all sizes must be installed flush with the ceiling.

Floor diffusers are installed at locations which are not continuously occupied. They can be deployed at distances of as little as 40 cm from seating

• Grilles with straight vanes project the longest throw. When the grille is located close to a ceiling, entrainment is restricted at the ceiling and results in a longer throw. However, when the air pattern is spread horizontally, the throw is reduced and the jet is flatter so its temperature is more uniform.
• Outlets with radial airflow have a short throw and a relatively thin jet, so the temperature in the jet is fairly uniform. Temperature equalizes more readily in a cooling jet, which results in less drop. • Single jets from ceiling outlets have a longer throw and perform like a grille. Outlets with high entrainment characteristics can also be used advantageously in air-conditioning systems with low supply air temperatures and consequent high temperature differentials between the room air and the supply air. Radial pattern ceiling diffusers may be used in systems with cooling temperature differentials as high as 30 to 35°F and still provide satisfactory temperature equalization in the space. Linear diffusers may be used with cooling temperature differentials as high as 25°F. Grilles may generally be used in well designed systems with cooling differentials up to 20°F.

Special diffusers are available for use with low temperature air distribution systems (i.e., those with supply air temperatures of 35 to 45°F and cooling differentials as high as 40°F). Those diffusers include special features that mix the cold supply air with room air at the outlet and effectively reduce the temperature differential between the supply and room air.