INDUL linear diffuser

Slimline linear diffuser for maximum thermal comfort and unobtrusive installation in all types of ceilings, even where space is at a premium. The reliable free jet characteristics prevent dirt deposits along the air diffuser, keeping ceilings clean for longer.

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INDUL strengths


The extremely high induction rate of INDUL linear diffusers enables draught-free operation even at very low supply air temperatures. This creates significant potential for saving energy through the use of free cooling.


The slender diffuser profiles blend perfectly into any ceiling architecture and keep ceilings dust-free for longer. Whether unobtrusive or deliberately accentuated, they will meet all architectural requirements.


INDUL free jet characteristics are unique in enabling a continuously diffuse ambient air flow and allow temperature differentials of down to -14 K, without the slightest compromise on thermal comfort.


The supply air is divided into fine alternating free jets, which intensifies the induction of ambient air. This high level of induction permits a substantial temperature differential between the ambient air and supply air, and in particular the use of free cooling. The required cooling capacity is reduced to a minimum. Effective insulation of the plenum box largely prevents energy losses despite the low temperatures. And thanks to the use of recycled aluminium, the INDUL air diffuser scores highly on lifecycle costs, as evaluated by current certification systems.

Air flow rate 20 - 250 m³/hm
Installation width 15, 18, 24 and 45 mm
Installation length 500 - 2500 mm
Special dimensions On request
Throat height 37 - 130 mm
Temperature difference Down to –14K
Classic INDUL ambient air flow

The classical ambient air flow

The specially developed discharge geometry produces fine individual air jets. Ambient air can be effectively induced at the edges of the individual jets. Through the induction (admixture) of ambient air, the temperature differential between the supply air and ambient air is balanced out over a short distance. The discharge velocity of the supply air is also reduced by the time it reaches the occupied zone, with the result that no draughts are perceived.

INDUL linear diffuser – air flow videos

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Installation situation

INDUL linear diffusers allow very narrow installation widths from as little as 15 mm. Available in different versions for an aesthetic ceiling design and maximum thermal comfort.


Quick and straightforward installation

INDUL installation accessories enable quick and straightforward installation and adjustment. The plug-in system for in-line and single installation has proven its worth many times over. Unique INDUL plaster bracket facilitates installation of INDUL linear diffusers in plasterboard ceilings. It also protects the discharge profile during painting and plastering work thanks to the protective strip supplied. Clean edges are created between the plasterboard ceiling and the air diffuser when the strip is removed.

INDUL N installation in metal-coffered ceilings

INDUL NA installation in mineral fibre ceilings

INDUL NG installation in plasterboard ceilings

  • check out the INDUL N product animation

    Visualised technical features of the INDUL N slot diffuser. Installation in various ceiling types with views of mounting options. Animated presentation of the special INDUL free jet characteristic. >> to INDUL product animation


  • INDUL linear diffuser

    At the Allianz SE Auditorium in Munich, Germany.

    Read on in the project report »


  • Foto © Roland Halbe

    INDUL at the Louvre, Abu Dhabi

    Intriguing effects of air and light at the Louvre in Abu Dhabi. Read on »

    Photo © Roland Halbe



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Kiefer Klimatechnik GmbH

Kiefer Klimatechnik GmbH is a leading company in the field of ventilation, air handling and air conditioning technology. Our range of services includes consulting, planning and execution of systems for thermal comfort and industrial air conditioning, as well as the associated installation and maintenance. For more than three decades, Kiefer has also been selling high grade ventilation components worldwide, such as linear diffusers, wall passages, displacement outlets, light and acoustic sails, chilled ceiling panels and concrete core cooling systems, developed in the company's own laboratories.

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