Inclined Floor Swirl Diffuser

Smartemp ISF-AD

The world’s only floor swirl diffuser with user-adjustable airflow rate, air motion and direction.

Floor swirl diffuser with rotatable, gentle inclined air breeze, adjustable to draught-free vertical air plume, provides displacement spread across the floor. VAV (user adjustable or electrically motorised) with constant throw to head height prevents cold feet / warm head at reduced airflow rate settings.

The SMARTEMP Inclined Floor Swirl Diffuser, type ISF-AD, is a high induction, low air velocity floor swirl diffuser for optimising occupant thermal comfort in “task-ambient” underfloor air distribution applications. The patent pending design provides users with enhanced personal control of their local thermal environment, minimises the vertical temperature gradient for seated occupants regardless of the airflow rate setting, and maximises face level indoor air quality.

User adjustment of both diffuser airflow rate and airflow direction allows users to customise their local temperature and air motion to achieve enhanced thermal comfort personalisation. The inclined discharge pattern of the diffuser maintains largely constant throw to head height of seated occupants regardless of the airflow damper setting, preventing throw from being reduced when the diffuser airflow damper is throttled.


Displacement airflow
Thermal displacement room airflow, with low level mixed flow supply into the occupancy microclimate. Displacement airflow spreads gently across the floor. Heat and contaminants rise to a high layer of stratification by natural convection. Enhanced levels of indoor air quality are attained in the breathing zone.

Floor location
Air supply from the floor, typically at least 500 mm from seated occupants.

Constant throw VAV
Substantially constant throw to head height of seated occupants regardless of the diffuser damper setting (adjustment by hand or by the optional VAV actuator). Prevents cold feet / warm head.

Adjustable direction & pattern
Airflow pattern adjustment from breezier inclined to almost imperceptible vertical plume. Airflow direction adjustment by rotation of the inclined airstream.

Manual adjustment
Airflow rate, pattern and direction adjustment are manual.

Circular face shape
200 mm nominal diameter round floor swirl face, plus mounting flange.

Radial face pattern
Substantially radially aligned swirl slots provide highly inductive swirl discharge.

Plastic face
Polycarbonate, dyed grey or to colour of choice (depending on quantity).

Airflow rate 

  • 10 – 55 L/s (36 – 198 m³/h)

Nominal size

  • DN200

Discharge height

  • 0 m


  • User-adjustable airflow rate.
  • User-adjustable inclined air stream direction.
  • User-adjustable air motion (gentle inclined breeze to draught-free vertical plume).
  • User-adjustability by rotation of the diffuser face.
  • VAV damper user-adjustable or electrically motorised.
  • Constant throw to head height of occupants throughout VAV damper range prevents cold feet / warm head at low airflow rates.
  • Low profile basket and damper assembly, suitable for shallow floor plenum.


International patent applications and granted patents are listed at


The SMARTEMP Inclined Floor Swirl Diffuser, type ISF-AD, is a low profile round floor swirl diffuser with user-adjustable airflow rate, air stream direction and air motiion, to maximimise individual thermal comfort. The patent-pending design allows user personlisation both of the localised effective air temperature by airflow rate adjustment, and of air motion. Air motion is user-adjustable from a gentle inclined breeze, which may be rotated towards or away from the user, to a draught-free, vertical plume, simply by twisting the diffuser face. No other floor swirl diffuser offers users such a high degree of thermal comfort personalisation.

User personalisation of air motion and of the direcitonal air pattern are available even when each floor swirl diffuser is equipped with an optional electrical VAV kit to provide motorised variable air volume operation.

When cooling, high induction, substantially vertical swirl discharge produces intense discharge velocity decay and rapid supply-to-room air temperature equalisation with throw restricted to head height of seated occupants. Cool supply air gently descends to spread as displacement airflow across the floor. An occupancy micro-climate of enhanced indoor air quality is created in which convective currents from occupants and other heat sources rise upwards in thermal displacement plumes. Heat and contaminants stratify in conentrated form at a high level, where they are removed from the space. High levels of indoor air quality and comfort are achieved.

Due to stratification of heat, relatively large supply-to-return temperature differentials are achievable – dependent upon ceiling height – despite the relatively high supply air temperature (typically 18°C), thereby minimising fan energy. Energy savings also accrue from the extended free cooling range often achieved by the elevated supply air temperature, as well as from the potential to reduce outdoor airflow rates due to the enhanced indoor air quality of the occupancy micro-climate.

High induction floor level swirl discharge ensures extremely effective heating performance, due to cool room air, which pools above the floor, being scavanged by the diffuser’s high aspiration, whilst thorough mixing diffuses the warm supply air into the occupancy space.

The patent pending design ensures enhanced indoor air quality in the breathing zone and eliminates the threat of cold feet / warm head (often experienced as “stuffiness”) even at reduced airflow rates. This is achieved by the substantially constant velocity discharge, which maintains throw of the inclined air stream to head height of seated occupants regardless of the airflow damper setting.

The diffuser is multi-configurable to suit the largely differing requirements of such disparate applications as offices, meeting rooms, transient spaces and reconfigurable applications. The aesthetically appealing face design, available in textured plastic or surface treated aluminium, compliments contemporary decor and is available in a multitude of custom colours.

The SMARTEMP ISF-AD Inclined Floor Swirl Diffuser is suitable for use in pressurised access floor air distribution systems, and may optionally be supplied with a side-entry connection box suitable for ducted air supply. A rapid mount assembly feature provides quick and easy installation or relocation without the need for tools or for access from below.

The SMARTEMP ISF-AD Inclined Floor Swirl Diffuser is available in selected markets as the LTG Boden-Drallauslass ILB.

Electric adjustment:
VAV motorised adjustment by means of electric actuator with 24V AC/DC power supply and 2-10 V analogue control input.

Metal face:
Anodised or powder coated cast aluminium finish.

Product Type

Face Material


Face Pattern

Face Shape



Airflow Direction



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