MHB Steel Windows & Doors

The Slimmest Steel Profile Systems in the World!

MHB's ultra-slim profiles combine superior technical properties such as outstanding thermal insulation and wind/water tightness with outstanding elegance resulting in unique products.

SL30-ISO Thermally Broken Steel Windows & Doors
The Beck Group
© Kurt Griesbach @ Corgan


Why MHB Steel Windows & Doors?

1 1/4" Wide Profiles

Our steel windows and doors through MHB offers the slimmest thermally broken profiles on the market. It's made by possible by applying smart engineering with steel's inherent strength to achieve similar widths across sightlines, mullions, and transoms for every window and door. Altogether, this means slim lines, large glazing, and maximizing the amount of light you can expect on every project.

Uniquely, all available MHB ISO profiles are thermally broken, producing U-Values and energy performance ratings that rivals are hard pressed to match.

MHB Steel Fixed Windows MHB Steel Windows, Doors, and Facades
MHB Steel Fixed Windows MHB Steel Windows, Doors, and Facades

Design Flexibility Through Steel

MHB’s patented profiles can be adjusted to fit different design styles without sacrificing performance, longevity, or strength. Whether your project calls for a traditional look of yesteryear or you’re pushing the boundaries with ultra-modernism, we can help you present a unified look across your entire project through fixed panels, radiuses, tilt-turns, multi-sliding doors, and more.

Landmark Status: Eligible

MHB Steel Windows and Doors are an ideal choice for restoration projects seeking landmark status. In possibly its most popular project, the Brenne Architects of Berlin utilized MHB's Classic-ISO series to bring new life into the famous Bauahus Institute campus. MHB was not only able to completely replicate the existing profiles, they enhanced the performance across the board through thermal breaks and smart drainage techniques.


Series & Collections

The SL30-ISO® Thermally Broken Steel Profile Series in a residence

The SL30-ISO

  • 1 ¼" Wide Profiles
  • Down to 0.16 U-Values
  • 99% Wind & Water Tight
  • Extra-Large Glazing Available


  • Casement Windows
  • Awning Windows
  • Sliding Windows
  • Speciality Windows
  • Multi-Slide Doors
  • Folding Doors
  • Entrance Doors
The SL30® steel door with an ultra-slim profile in a residence

The SL30

  • Ultra-slim sightlines at 1 1/4"
  • Free Form Partitioning


  • Interior Doors
  • Interior Window Walls
A Classic ISO® radius window in a residence

The Classic-ISO

  • Ideal for Landmark Projects
  • Thermally Broken
  • 1 3/16" Sightlines, Mullions, and Mutins
  • Freeform Partitioning


  • Casement Windows
  • Awning Windows
  • Speciality Windows


Thermally Broken Profiles with MHB Steel Windows and Doors

Thermally Broken Profiles

Patented thermal break technology used in all of our ISO systems enhance your performance and saving on energy costs.

99% Wind and Water Resistance with MHB Steel Windows and Doors

99% Wind & Water Resistance

Invisible Drainage Caps keep water from passing through to your valuables and smart engineering keeps wind from passing through.

Low U-Values with MHB Steel Windows and Doors

Low U-Values

Rigorously measured and tested by ATI, MHB steel windows and doors are NFRC tested with specific forms available per project.

Extra Large Glazing with MHB Steel Windows and Doors

Extra Large Glazing

Order doors up to 12 feet tall and up to 48 inches wide thanks to the unique strength that steel can hold at half the structural footprint aluminum requires.

Bespoke Hardware with MHB Steel Windows and Doors

Bespoke Hardware

Choose from stock options or have your hardware custom created for you by MHB engineers.

Custom Partitioning with MHB Steel Windows and Doors

Custom Partitioning

Steel's inherent strength can maintain structural integrity across transoms and mullions allowing for partitions to be made at the architects descretion.