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The Richmond Designer Aluminium Front Door

Discontinued Product

Alitherm Plus has been superseded by the new and improved Smart Designer Door with unbeatable strength and security

Smart Designer Doors - Find out more here

Alitherm Plus - No longer available



Part of the successful Alitherm range of domestic doors & windows, the Alitherm Plus Door is suitable for all residential use. Also for light commercial applications such as entrance doors to apartment buildings.


Key Features

  • Elegant, strong and durable.
  • Keeps the warmth in AND adds extra light thanks to slim sightlines.
  • Enhanced security with multipoint locking system.

Wow! The Alitherm Plus Aluminium Front Door with side lights installed in Baildon, Bradford



Rated 5.0 out of 5 David Lister

"Top rated! Efficient and excellent work. Very friendly with skilled fitters. Would highly recommend."


Read this and our other 5 star reviews left on Google




Alitherm Plus can now be fitted with a Designer Panel range, carefully selected to suit a wide range of house and apartment styles. Designer Panels make a striking design statement for the discerning home-owner.

Alitherm Plus is available in a choice of standard and non-standard colours, with single and dual colour options including Smart’s own Naturals, Sensations, Alchemy and Cotswold colour ranges.


Just choose your preferred style then

Product Information

The Alitherm Residential Door takes its place alongside the Alitherm 47 Door, giving the option of a robust performance, domestic entrance door and an alternative to the Visoline light commercial door.

Fabricator & Fitter friendly; the new Alitherm Residential door is designed to be easier to manufacture and install. New adjustable hinges, lock keeps and additional sash passing clearance allow for greater on-site fitting tolerances.   

  • New adjustable hinges and lock keeps
  • Single & double doors use multi-point locking mechanisms 
  • Double doors feature dual lock mechanisms enabling handles on both sashes
  • Door sections & hinges are designed with added strength delivering robust performance
  • Internally beaded for open in and open out doors
  • Profiles are contemporarily styled with a modern, square-edge design
  • Low thresholds comply with Document M building legislation
  • Z/T sash sections allow for greater coverage and weather resistance
  • Tested in accordance with the requirements of BS 6375 Pt1 and achieved the following classification for weather tightness
  • Air Permeability 600pa
  • Water Tightness 600pa
  • Wind Resistance 1200pa
Alitherm Plus residential door profile

Document Downloads

File Type Document Description Download Document
Adobe PDF Alitherm Series
Supply only – Guide to installation
Download (403kb)

Technical Specification


Product Type Doors
Material Aluminium Polyamide
Dual Colour
Thermally broken


Max width 900
max height 2400
Max weight 80
Weather suitability ★★★★★
Acoustic suitability ★★★★
Thermal suitability ★★★★
Min Glazing 24
Max glazing 32
low threshold option


BS6375 Pt 1

Locking options


Frame options

Even leg
Direct Fix

Door options

Butt hinge



Building suitability

light duty
medium duty
Glazing and frame colour choice


Our aluminium profiles are polyester powder coated by our systems suppliers using the very latest paint application techniques guaranteed for 25 years.

Fully compliant to the latest June 2022 building regulations our standard double glazing is the exceptional light transmitting, energy saving ClimaGuard® A+ low emissivity (Low-E) glass manufactured by Guardian Glass.

Read More


Rated 5.0 out of 5 Trevor Paterson

"I would highly recommend Marlin window, the company are a pleasure to do business with, the window's and door's look fantastic.


Excellent service from initial contact through to delivery and beyond :) . Big thank you to Adrian, Hannah and the rest of the team."


Read this and other 5 star reviews of Marlin Windows left on Google


Modern aluminium windows installed at new build property in Ilkley in Yorkshire

Contemporary Doors & Window Image Gallery

See more pictures to inspire in our contemporary aluminium door and window gallery


Why Choose Marlin Windows?

We care...

about the quality of finish
about you, your project and your property
about your 100% satisfaction

And we are rated ★★★★★ on Google

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"our builder said they were the best supplier and fitter they had ever used"
Mrs Nellist Haworth, Yorkshire


Call 01535 603909