Thermal Rated Doors
Designed for external, internal, commercial and industrial applications
Optional fire-rated, acoustic, vision panel and side panel specifications
Thermally efficient steel doorsets with U-values as low as 1.4 W/m²K
Strong steel construction for secure commercial and industrial use
Thermal Rated Steel Doors for Energy-Efficient Buildings
Thermal-rated doors provide a robust and energy-efficient solution for buildings where heat loss, weather resistance and long-term durability are key considerations. Designed for commercial, industrial and public-sector environments, these doorsets combine the strength of a steel door with enhanced thermal performance.
Maxium Doors supply and install thermally efficient steel doorsets that can achieve U-values as low as 1.4 W/m²K, depending on the required specification. They are ideal for external entrances, plant rooms, warehouses, service areas and other locations where a standard steel door may not provide the required level of thermal insulation.
Thermal-rated doors can also be specified with additional performance options, including fire resistance, acoustic control, vision panels, side panels and a wide choice of powder-coated finishes.
Key Features
- Thermally efficient steel doorsets for commercial and industrial use
- U-values achievable down to 1.4 W/m²K, depending on specification
- Suitable for internal and external applications
- Mineral wool core with internal strengtheners
- Anti-jemmy leading edge for improved security
- Weld-free construction to help prevent premature failure
- DDA-compliant threshold options available
- Optional fire ratings up to 120 minutes
- Acoustic rated option available
- Custom vision panels, side panels and over panels available
- Powder-coated in any RAL colour, with marine-grade and special finish options
Built for Thermal Performance
Thermal rated doors are designed to help reduce heat transfer through the doorset, supporting the wider energy performance of the building. The Defender Thermaguard doorset uses a combination of insulated door leaf construction, deeper frame profiles and high-performance seals to achieve improved thermal efficiency.
Depending on the required configuration, U-values of 1.5 W/m²K or 1.4 W/m²K can be achieved. This makes thermal rated steel doors a strong option for projects where energy efficiency, Building Regulations Part L considerations and long-term building performance are important.
Strong Steel Construction
These doorsets are built using galvanised steel, with a mineral wool core and internal strengtheners for durability and insulation. The door leaf can be specified with a minimum depth of 60mm or 70mm, depending on the required thermal performance.
The leading edge includes an anti-jemmy flange for additional protection, with a square-edged option also available where required. Frames are manufactured with bolted corners, threaded adjustors for installation and steel hinge brackets for a strong, secure fit.
Options & Customisation
Thermal rated steel doors can be tailored to suit the building, application and performance requirements. Options include fire-rated upgrades, acoustic performance, vision panels, over panels, side panels and a wide range of hardware choices.
Finishes include powder coating in any RAL colour, with marine-grade coating available for more exposed environments. Textured, metallic and woodgrain finishes can also be specified where appearance is an important consideration.
Supply Only or Full Installation Services
Thermal rated doors can be supplied directly to contractors, developers and facilities teams for installation as part of a wider project. Doorsets are manufactured to specification and can be provided with the required frame, threshold, hardware, finish and glazing options.
For projects requiring a managed service, Maxium Doors can also provide full installation. This includes specification support, site coordination, professional fitting and final checks to ensure the doorset is correctly installed and suitable for its intended use.
Why Maxium
Maxium Doors supply high-quality commercial steel doors designed around the requirements of each project. Our thermal-rated doors are made to measure and can be specified with the right combination of thermal performance, security, fire rating, hardware and finish.
We work with contractors, developers, facilities managers and commercial clients across the UK, offering practical specification advice, reliable supply and professional installation where required. Whether you need a single thermal-rated doorset or multiple doors across a wider development, our team can help you choose the right solution.
Yes. Thermal rated steel doors are suitable for external applications and are designed to support improved insulation, weather performance and building efficiency.
Depending on the specification, thermal rated doors can achieve U-values of 1.5 W/m²K or as low as 1.4 W/m²K.
Yes. Fire-rated options are available for internal or external use, with ratings up to 120 minutes depending on the required specification.
Yes. Custom-sized vision panels can be specified, including triple glazed options with privacy films, obscure glass or patterned glass.
Yes. Thermal rated doors can be powder coated in any RAL colour. Marine-grade finishes, textured finishes, metallic finishes and woodgrain effects are also available.
British Made With Quality Materials
Free Design Consultations
Made To Measure For The Perfect Fit
Experienced Sales Team
Project Managed By Our UK Based Team
Nationwide Delivery And Installation
Applications and Typical Use Cases
Thermal rated doors are commonly specified where an external steel door needs to provide both security and improved insulation. They are particularly suitable for plant rooms, warehouses, service corridors, commercial entrances, industrial buildings, schools, healthcare sites and residential developments.
They can also be useful where internal areas have different temperature zones, or where the door forms part of the building envelope and needs to contribute to the overall energy performance of the property.
Thermal Performance, Fire Rating and Acoustic Options
Thermal rated doors can be configured to meet different project requirements. Depending on the specification, U-values of 1.5 W/m²K or 1.4 W/m²K are achievable. Fire-rated options are also available for internal or external use, with ratings of up to 120 minutes.
Where noise control is a consideration, acoustic-rated options can also be specified. This makes the doors suitable for a range of commercial and industrial applications where more than one performance requirement needs to be met within the same doorset.