Air diffusers

We ensure the best possible indoor air quality. Precision and quality ensure the optimal supply of air. 

Roof bonnets

Standard version

As deflector hood with internal rain collection funnel at an angle of >19°. Streamlined design with duct connection flange and bird screen. Made of galvanized steel, stainless steel or aluminum in sheet thicknesses of 0.7 - 1.2 mm. Construction in reinforced industrial version possible.

roof bonnets

Special versions

Deflector bonnet round folded | BLH Lüftungstechnik

DFH round with standing rabbets

Deflector bonnet round welded | BLH Lüftungtechnik

DFH welded

Roof ventilation attachment | BLH Lüftungstechnik

Roof ventilation attachment

Louvre bonnet | BLH Ventilation Technology

Louvre bonnet

Roof bonnet | BLH Ventilation Technology

Roof bonnet

Outside air bonnet | BLH Lüftungstechnik

Outdoor air bonnet

Roof plinth

Standard version

Our roof bases are used to securely hold ducts or roof bonnets. They are available as square or round variants. Likewise, they are available as reinforced, welded versions to take loads. Insulation and materials such as stainless steel or aluminium are also possible.

Roof plinth

Assortment of variants

Roof base - insulation inside or double-walled | BLH Lüftungstechnik

Insulation inside or double-walled

Flat roof base sloping | BLH Lüftungstechnik hennen

Version for pitched roof

Roof base - roof duct | BLH Lüftungstechnik

Design as roof duct

Roof ducts-round | BLH Lüftungstechnik Hennen

Design as round roof duct

Variable weather protection grille | BLH Lüftungstechnik


round | triangular | oval | trapezoidal - other shapes are manufactured individually

weather protection grille

Standard version

weather protection grille

Assortment of versions

Variable weather protection grille | BLH Lüftungstechnik

Version as Sloping roof weather protection grille

Horizontal weather protection grille | BLH Lüftungstechnik

Design as horizontal weather protection grille

Rain collar

Standard version


The rain collar is used to protect the mounting openings from rainwater. It is available in round or square form. Mounting either directly on the product or supplied loose in a two-part design. With welded tabs or for sliding into each other.

lamella bonnets

Standard version

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available in


Impressions of our air diffusers