Alitherm Heritage 60 Doors
Enhanced Thermal Performance for Refurbishment & New Build
Enhanced Steel-Look Door Performance
Alitherm Heritage 60 Doors
The Alitherm Heritage 60 door takes our original steel-look aluminium door system and builds in extra frame depth for even better thermal performance, making it the door we recommend most for refurbishment projects, apartment conversions and new builds in sensitive conservation areas.
It keeps the distinctive slim sightlines of the Alitherm Heritage range while going further on U-values.
Explore Our Heritage Door Systems
Which Heritage Door Is Right for You?
Alitherm Heritage 60 is the performance upgrade within our heritage door range. If you don’t need the extra frame depth, standard Alitherm Heritage offers the same steel-look styling with a shallower profile; Sheerline Classic has a stepped Art Deco look; and the AluSpace internal system brings the styling indoors.
See the Full Heritage Door Range →Compare all four heritage door systems.
What Is Alitherm Heritage 60?
Alitherm Heritage 60 takes its name from its enhanced 67.5mm frame depth – deeper than the standard Alitherm Heritage system, designed specifically to improve thermal performance without losing the slim, steel-look sightlines that define the range. It’s a direct replacement for original steel doors, and it’s the version we point refurbishment and new-build clients towards when Document L compliance and long-term running costs matter most.
Key Features
U-values from 1.4 W/m²K (double glazed) down to 1.2 W/m²K (triple glazed with Krypton), fully compliant with Document L of the UK building regulations
67.5mm frame depth with polyamide thermal break technology
PAS24 Secured by Design accredited
Multi-point locking, with a full range of stainless steel hardware including heritage and Art Deco handle options
Single or dual-colour marine grade quality polyester powder coat paint finish as standard
10-year manufacturer warranty, 25-year paint finish guarantee
Max sash dimensions – 900mm wide and 2100mm high; single and double doors, with open-out and open-in options
Why Choose Alitherm Heritage 60?
Alitherm Heritage 60 trades a small amount of extra frame depth for meaningfully better thermal performance and PAS24 security accreditation as standard, where the standard Alitherm Heritage system keeps the shallower 47mm frame. That makes it the door of choice for conservation areas where planning requires a like-for-like steel aesthetic, but the building itself needs to meet modern energy standards – refurbishments, apartment conversions and new-build heritage-style homes in particular.
”Jordan was absolutely amazing from start to finish, very happy with our doors and the service provided. Five stars all round!”
Sophie du Toit – Bedford
Suitable for Listed Buildings, Conservation Areas & New-Build Homes
The Alitherm Heritage 60 system’s slim profile and traditional styling have been approved for listed building and conservation area projects by a number of local authorities, including the London Boroughs of Islington, Camden and Tower Hamlets, Watford Borough Council, Essex County Council, Leeds City Council, and Cadw. As with any listed building project, final approval depends on your specific property and local authority.
We also offer a free sample service to help with surveying decisions, design choices or planning applications – just call us on 01535 603909 and ask.
Why Homeowners Choose Marlin
As a family-run manufacturer of heritage aluminium systems in Keighley, West Yorkshire, we combine over 20 years of expertise with quality materials and a 10-year warranty for complete peace of mind.
“Jordan was absolutely amazing from start to finish, very happy with our doors and the service provided. Five stars all round!” — Sophie du Toit, Bedford
“Marlin Windows were reassuringly professional, calm & helpful from first contact… I honestly think it’s a rarity these days to come across a company with values like Marlin so 5*s well-deserved.” — Anne Corrigan, Hale, Altrincham
I honestly think it’s a rarity these days to come across a company with values like Marlin so 5*s well-deserved.”
Anne Corrigan – Hale, Altrincham
Visit Our Keighley Showroom
For inspiration, help and advice, visit our showroom in Keighley, West Yorkshire. You can visit by appointment Monday to Friday 9am to 4:30pm, Saturday 8am to 12 noon, or by special arrangement outside of these times – see the largest selection of Heritage steel-look windows and doors in the UK, compare frame styles, sightlines and finishes side by side, before you decide.
Just call 01535 603909 to book.
Supply & Installation Options
Choose professional installation across our regional service area or nationwide supply-only delivery.
Supply & Install
Professional survey and installation across West & South Yorkshire, Greater Manchester, Merseyside, Lancashire, Derbyshire, Nottinghamshire, East Riding and Cheshire.
Supply Only – Nationwide
Made to measure in Yorkshire and delivered nationwide, ready for your builder or installer.
Outside our installation area? We can still supply and deliver nationwide.
Document Downloads
Alitherm Heritage 60 Data Sheet
Helpful guides
IS ALUMINIUM A SUITABLE ALTERNATIVE FOR THE REPLACEMENT OF STEEL PRODUCTS?
Steel look Aluminium Windows, Doors and Internal Room Dividers and Doors look very similar to their Steel counterparts but offer several benefits of being Aluminium.
The benefits of modern, secure, thermally efficient aluminium windows with the heritage and character of traditional steel at a fraction of the cost.
Latest projects
Ready to transform your home?
Get a made-to-measure quote for your Alitherm Heritage 60 doors today. Our team will guide you through sizes, styles and glazing options to find the perfect fit for your home.
Or call us on 01535 603909 to speak with our team.
Frequently Asked Questions
How energy-efficient are they?
U-values from 1.4 W/m²K (double glazed) to 1.2 W/m²K (triple glazed with Krypton), fully compliant with Document L of the UK building regulations.
Are they suitable for listed buildings or conservation areas?
Yes, subject to approval by your specific local authority.
How long do Alitherm Heritage 60 doors take to make?
We can typically have your doors ready within around 4 weeks for supply only, though lead times vary by season and project size – please contact our team for a current estimate.
Are they PAS24 accredited?
Yes, PAS24 Secured by Design accredited as standard.
What information do you need for a quotation?
Approximate dimensions (width x height), a basic design or layout, and your project location.
How is Alitherm Heritage 60 different from standard Alitherm Heritage?
The deeper 67.5mm frame, against the standard Alitherm Heritage profile’s 47mm, gives a meaningful thermal upgrade and adds PAS24 accreditation as standard. We recommend it for refurbishments and new builds where Document L compliance matters most.
Come and explore…
Aluminium Bi-fold Doors, Sliding Doors, Contemporary Glazing, Aluminium Heritage Windows and Traditional Steel Replacement Doors
