Step H, Horizontal, 4 elements, Hight 430 mm, Lenght 1500 mm, Quartz 2


When a successful company like Irsap discovers the stylistic synthesis of Antonio Citterio, the result in terms of both aesthetics and performance is impeccable. Our meeting led to the development of a line of authentic design heating elements that speaks the immediately recognizable language of a designer who symbolizes Made in Italy spirit and production. These are products that can be easily inserted in any surroundings thanks to the discretion adopted in their physical configuration. Every single detail has a simple story and a truth to tell: fashion trends come and go without a trace, true design, instead, leaves its mark. Design remains at the disposal of anyone who designs interiors and those who desire to fill these rooms and areas with their own desires and dreams.

Antonio Citterio

The STEP range offers the synthesis of simple and clean lines, peculiarities universally recognized in the works of Antonio Citterio. With STEP, IRSAP invites you to experience the home. STEP_H is the version with horizontal development, made with large 70 mm slats. Thanks to its harmony of shapes and its multiple sizes, Step_H is adaptable to any room in the house.

Construction features

flattened pipes in aluminium, 70 mm width

maximum working pressure 4 bar

maximum working temperature 95°C


High care and attention to details is our guiding principle. STEP heating elements are the quintessential expression of this approach. Every product has been carefully studied to the finest detail, such as the adjustable wall connections patented by IRSAP.

Colors and Finishes
Attention: the colors displayed are indicative and could not be as real radiators.
Model Deph  (mm) Height (mm) Width (mm) Conn. C. (mm) Weigth (kg) Capacity (lt) Δt=50°C (btu/h) Δt=50°C (kcal/h) Δt=50°C (Watt) Δt=40°C (Watt) Δt=30°C (Watt) Δt=20°C (Watt) Exponent
STEP_H_1500_03 el. 107,0 310 1500 1276 9,07 1,98 1.588,8400,2465,6350,7243,3145,51,269
STEP_H_1800_03 el. 107,0 310 1800 1576 10,26 2,37 1.906,5480,3558,6420,9292,2174,61,269
STEP_H_1500_04 el. 107,0 430 1500 1276 12,28 2,65 2.128,8536,4624,0470,4326,8195,61,266
STEP_H_1800_04 el. 107,0 430 1800 1576 13,86 3,17 2.554,4643,6748,8564,4392,0234,81,266

(*) Thanks to the high performance of Irsap STEP_H radiators, the ideal Δt for low temperature projects is Δt at 30°C. The heating yields are calculated on products with epoxy powder coatings. For Chrome (code 50) finishes, the yields decrease respectively by 40%. All the available finishes are shown on the facing page.

For Δt different from 50°C use the formula: Q=Qn (∆t / 50)n


Standard equipment

• wall fixing systems the same finish as the radiator • 2 hidden vent valves of 1/2” and valve caps • pre-mounted hydraulic connection kit in the same finish as the radiator, complete with couplings for copper fittings (diameter 12, 14 and 15 mm), and multilayer pipes (14 x 2 thick and 16 x 2 thick)


Installation Manuals


3D models


3D models


3D models


3D models


3D models

Catalogue 2022




Color chart 2022



Dimensional drawings