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Alitherm casement window
Long casement steel look windows

Versatile system for residential and commercial properties

At Direct Trade Windows, we expertly install aluminium casement windows in both commercial and residential properties.

Using Smart’s Alitherm Heritage model, this versatile system is an excellent addition to any property, and is ideal for projects that require planning permission.

Our casement windows are:

  • Versatile – Fixed, single or double sash, top hung, tilt & turn, or pivot options.
  • Thermally efficient – Polyamide thermal break enhances thermal efficiency.
  • Durable – Perform consistently for several decades without wear and tear.
  • Secure – Equipped with full PAS24 accreditation.
About Us

Trusted manufacturers since 2000

Professional Installer Network

Quick Supply

Made in the UK

Exceptional Quality Control

Knowledgeable Family Run Business

Bespoke Complex Products Fabricated

Alitherm Heritage Casement Windows

Alitherm Heritage casement windows are built as a series of horizontal modules which can be stacked using horizontal couplers from a multi-part window featuring a specially designed drip bar between modules.

  • U-value of 1.5 W/m²K
  • Document L compliant
  • PAS24:2016 accredited
  • Fixed, tilt & turn, side hung or top hung casements available
  • Polyamide thermal break provides enhanced thermal performance

Dimensions:

  • Side hung maximum width: 600mm
  • Side hung maximum height: 1400mm
  • Top hung maximum width: 1400mm
  • Top hung maximum height: 1400mm
  • Fixed maximum width: 2100mm
  • Fixed maximum height: 2100mm
Contact Us
Classic Alitherm casement windows
  • Alitherm Heritage Casement Windows
  • Colours
  • Glass Options
  • Hardware Options
  • Downloads
  • Alitherm Heritage Casement Windows

    Technical Specification

    • Brand Alitherm
    • Material Aluminium Polyamide
    • Dual Colour Yes
    • Thermally Broken Yes
    • NBS Available Yes
    • WER Rating B
    • U Value 1.5W/m²K (using 1.0W/m²K glass unit)
    • Document L Compliant Yes
    • Kitemark Yes
    • BS 6375-1:2009 Yes
    • BS 4873 Yes
    • Side Hung Max Width (mm) 600
    • Side Hung Max Height (mm) 1400
    • Top Hung Max Width (mm) 1400
    • Top Hung Max Height (mm) 1400
    • Fixed Max Width (mm) 2100
    • Fixed Max Height (mm) 2100
    • Single Door Max Width (mm) 900
    • Single Door Max Height (mm) 2100
    • Glazing (mm) 24, 28, 32 & 36 double or triple glazed units
    • Frame Depth (mm) 47
    • Typical Sightlines (mm) 59
    Alitherm Heritage open window

    Colours

    Colours

    Pure White RAL-9010

    Pure White RAL-9010

    Matt White

    Matt White

    Matt Brown

    Matt Brown

    Jet Black RAL-9005

    Jet Black RAL-9005

    Grey

    Grey

    Gloss White

    Gloss White

    Gloss Off White

    Gloss Off White

    Dark Red

    Dark Red

    Dark Grey

    Dark Grey

    Dark Green

    Dark Green

    Dark Brown

    Dark Brown

    Dark Blue

    Dark Blue

    Cream

    Cream

    Black

    Black

    Anthracite Grey RAL-7016

    Anthracite Grey RAL-7016

    Airforce Grey

    Airforce Grey

    Glass Options

    Glass Options

    Unglazed

    Unglazed

    Standard Self Clean

    Standard Self Clean

    Standard Tough

    Standard Tough

    Solar Control

    Solar Control

    Self Cleaning

    Self Cleaning

    Self Clean Solar Control

    Self Clean Solar Control

    Satin Obscure

    Satin Obscure

    Laminated Security

    Laminated Security

    Hardware Options

    Peg Stay Monkey Tail & Pear Drop

    Peg Stay Monkey Tail & Pear Drop

    Peg Stay Catch

    Peg Stay Catch

    Pear Drop Handle

    Pear Drop Handle

    Monkey Tail Handle

    Monkey Tail Handle

    Dummy Butt Hinge

    Dummy Butt Hinge

    Standard Handle Brass

    Standard Handle Brass

    Standard Handle Satin

    Standard Handle Satin

    Standard Handle Chrome

    Standard Handle Chrome

    Standard Handle White

    Standard Handle White

    Standard Handle Black

    Standard Handle Black

    Downloads

    Gallery

    Aluminium Casement Windows - Your Questions Answered

    Explore common questions about our Aluminium Casement Windows, suitable for both residential and commercial properties. Discover how these windows offer durability, performance, and energy efficiency.

    Get a Free Quote for Alitherm Heritage Casement Windows

    What are Aluminium Casement Windows, and where can they be installed?

    Aluminium casement windows are a versatile window system suitable for both residential and commercial properties. They can be installed in various settings, including homes, offices, and other commercial buildings.

    What are the key features of these casement windows?

    These casement windows offer versatility with options such as fixed, single or double sash, top hung, tilt & turn, or pivot styles. They are thermally efficient thanks to a polyamide thermal break, built for long-term durability, and equipped with full PAS24 accreditation for security.

    How energy-efficient are Alitherm Heritage Casement Windows?

    Alitherm Heritage Casement Windows have a U-value of 1.5 W/m²K, making them energy-efficient and compliant with Document L standards. The polyamide thermal break enhances their thermal performance.

    Can I get custom dimensions for these casement windows?

    Yes, you can. Depending on your needs, you can choose from a variety of dimensions for side hung, top hung, and fixed casement windows, providing flexibility for different project requirements.

    Are these windows suitable for projects that require planning permission?

    Yes, these casement windows, particularly using Smart's Alitherm Heritage model, are ideal for projects that require planning permission due to their versatile and high-quality design.

    Close up view of steel look windows

    Delighted Customers Share Their Experiences

    At Direct Trade Windows, our commitment to excellence is reflected in our exceptional customer satisfaction.
    We take great pride in our impressive 4.9 rating on Google, a testament to the unparalleled quality and service we offer.

    Check Out Our Google Reviews

    We had been severely let down by a previous supplier, but when we turned to Direct Trade Windows for help, we hit the jackpot. Helping us to transform a residential development in Hersham, they supplied us with high-quality, ultra-slim Cortizo sliding doors, complete with the bespoke sliding options that we needed. Our requirements were very specific and not readily available on the market, but Direct Trade Windows really went the extra mile to help us out, coming through with quality products and excellent service. We will definitely be using their services again.

    Park Lane Developments

    2022

    Nothing but praise for this outfit. It was a pleasure to work with them. It was a nerve-wracking undertaking for us, the biggest single expense to fit three large window/french door combos in our extension, yet the team made it a relatively relaxing experience with their professionalism and good humour. Thank you all so much for everything you and the whole team have done to get from the initial sale (well done Hash!) to the fun visit we made to the workshop, to the design and its multiple iterations (thank you Taz!) and finally to the installation. Thoroughly recommended.

    Eloise Price - 2022

    Direct Trade recently replaced a large, faulty sky light. They said they’d take 3 hours, they took two. They did a fantastic job, there was absolutely NO dust or mess, at all. I was amazed… thought I’d be clearing up dust for days! I also didn’t need to get the recess re-plastered or painted – bonus!

    I highly recommend Direct Trade. They are a professional and friendly service delivering a high quality product.

    Vicky Steele - 2022

    I met with Taz at the warehouse to see some examples of the glazing and from the beginning he was extremely professional, personable and helpful. We ordered crittal style windows and doors, a Juliet door, 3 other windows and roof lights and every one of them was excellent quality, secure and well made. I highly recommend Taz and his team at Direct Trade Windows!

    Nick Robinson - 2021

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