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Diamond Windows are a registered FENSA installers

We adhere to a strict code of quality. We notify FENSA whenever an installation has been completed.

Alitherm Heritage

As the name suggests, Alitherm Heritage solutions are ideal for substantial replica refurbishment projects, as well as listed building renovations. This is because planning restraints must be considered, and Alitherm Heritage windows are perfect for such situations. The unique design means that windows can be built as a chain of horizontal couplers, resulting in a multi-part window.

These windows are built with a polyamide thermal break technology, meaning that a barrier is formed between the internal warm air and external cold air. Consequently, thermal transmittance is significantly reduced, resulting in an enhanced U Value that successfully meets the requirements of Document L 2010.

Alitherm Heritage windows undergo tests to ensure security and durability against adverse weather conditions. Not only do they meet PAS 24:2016 and BS 6375 Part 1:2009, but they also adhere to British Standard Kitemarks KM 81543 and KM 81580.

Our aluminium casement window styles are a popular choice for homeowners because of their classic, chic appearance and ‘A’ energy rating, ensuring your home retains heat, saves you money, and looks good doing it.


Brand: Alitherm

NBS Available: Yes

Thermally Broken: Yes

Dual Colour: Yes

Material: Aluminium Polyamide


BS 4873: Yes

BS 6375-1:2009: Yes

Kitemark: Yes

Document L Compliant: Yes

U Value: 1.5W/m²K (using 1.0W/m²K glass unit)

WER Rating: B


Single Door Max Height (mm) : 2100

Single Door Max Width (mm): 900

Fixed Max Height (mm): 2100

Fixed Max Width (mm): 2100

Top Hung Max Height (mm): 1400

Top Hung Max Width (mm): 1400

Side Hung Max Height (mm): 1400

Side Hung Max Width (mm): 600

Typical Sightlines (mm): 59

Frame Depth (mm): 47

Glazing (mm): 24, 28, 32 & 36 double or triple glazed units


As listed above, the Alitherm Heritage collection can be applied in all manner of ways, including top hung, side hung, tilt-turn, or fixed solutions. You can be sure you’ll find what you’re looking for when it comes to Alitherm Heritage.


Alitherm Heritage windows are designed to seamlessly replace steel windows, using single or dual colour, marine quality polyester powder coat as standard. Despite this, there are 316 Marine Grade Stainless Steel Hardware options also available. Whether you’re looking for standard Heritage solutions or Art Deco hardware, we have the frames to suit.

Alternative Styles

The beauty of Aluminium is that it's available in any single or dual RAL colour so you are sure to find the perfect colour for your home.


You can even choose your desired glazing finish, including sqaure or diamond lead work. Whether you need simple replacements for your upstairs rooms or a more ornate solution for your bay living room, Diamond Windows Droitwich has a wide range of aluminium windows for sale, ensuring we have something to suit your style.

10 Year Guarantee

All of our double-glazed casement windows are easy to maintain and keep looking like new, partly due to their durability and longevity. We’re so confident in our windows that we offer a ten-year guarantee as standard.

Shop Alitherm Heritage with Diamond Windows

We’re proud to call ourselves double-glazing specialists and we operate throughout the West Midlands region. Therefore, when it comes to searching for window solutions, Diamond Windows must be considered. Contact us to find out more about our Alitherm Heritage range, installation services, or any other products. We look forward to hearing from you.

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“Very pleased with work carried out. Approachable staff very pleasant.”

“The Diamond Window guys installed our new front door and sidescreen and did a fantastic job. They were highly skilled and also very tidy. I would use them again”

Trust our 5-Star Reviews

“Excellent selection, first class advice and outstanding fitting. We wouldn't go anywhere else for double gazing projects.”

“From design to completion , excellent service,friendly and competent tradesmen.”

Contact us
Diamond Windows, Unit 22, Northstreet I.E, Droitwich,West Midlands, WR9 8JB
Company Reg: 5367399
Open Hours
Mon to Fri: 9am to 4.30pm
Sat: 9am-1pm
Sun: By appointment