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Triple Glazed Aluminium Windows


Klosen / Aluminium Windows / Triple Glazed Aluminium Windows

slimline sliding doors stone house
New upstairs window in an old brick wall
Heritage Windows


If you want ultra-modern, flush-fit windows but don’t want to compromise on thermal and sound insulation, there’s no better option on the market than triple-glazed aluminium windows.

Whether you’re hoping to modernise an ageing home or you’re building a new property, you won’t have to settle for anything less than the best with Klosen: all of our aluminium window and door installations are guaranteed for a decade.

Combining world-class products from leading manufacturers with experienced, highly-trained technicians, we’re the go-to supplier of double and triple-glazed aluminium windows in Peterborough (and the surrounding areas).

To find out more, download a brochure or request your free quotation.

Are Triple-Glazed Windows Worth Choosing?

Although double-glazed windows have now become the industry standard, many homeowners are now turning to triple-glazed windows instead. Why? Here are a few key attributes that make them worth the extra cost:

Energy bills are higher than ever. Triple glazing is much more efficient than double glazing, allowing it to keep more heat in and, in turn, saving you money on your heating bill. The transformation will be particularly noticeable if you’re replacing old double glazed windows.

As well as boasting improved thermal insulation, triple glazing is better at insulating sound too. Whether you’ve got roadworks going on outside or are unlucky enough to have a noisy neighbour, the sound will be less intrusive with triple glazing installed.

Triple glazing is tougher. If you’re concerned about home security, triple glazing is well worth considering as it’s significantly harder to break.

The improved thermal efficiency of triple glazing means you’re less likely to experience condensation during the cooler months.

Why Choose Aluminium?

Aluminium-framed windows are an exciting, ultra-modern alternative to more traditional wood or PVC options. Because of aluminium’s inherent strength, window frames constructed from it can be slimmer than any wood or PVC frame without compromising on security, allowing for the fitment of larger panes of glass to let more natural light into your home.

Besides their stunning looks, aluminium windows are immensely durable – much more so than PVC or wood equivalents. They won’t rust, rot or crack over time, so when you choose aluminium, you really are making a long-term investment in your property.

They’re also no more challenging to install than conventional windows. Here are just a few of the installations we’ve recently completed:

Brands We Work With

We recognise just how significant an investment windows are: when you fit them, you expect them to last and still look good in 10 years’ time (or even further into the future). That’s why we only work with top-tier suppliers.

Cortizo and Senior Architectural Systems are renowned across the industry. Each manufacturer boasts a vast product range, with designs available to suit practically any application and a comprehensive choice of finishes.

We’re that confident in the quality of these products (and our installations) that we guarantee each and every one for 10 years.

Download a brochure today to learn more.

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Senior Architectural Systems Logo
Cortizo Logo

10 Year Guarantee

We offer a 10 year guarantee on all aluminium profiles and 25 years for the powder coating element

Thermal Efficiency

Stay warm in the winter and cool in the summer whilst cutting down on energy bills

Complete Flexibility

Our team are flexible throughout the entire process, including the design and installation of windows

25+ Years Experience

Klosen have over 25 years experience working with designers, architects and homeowners


Since 1972, Spanish company Cortizo has been leading the way in the manufacture of aluminium windows and doors. Working exclusively with aluminium, Cortizo has established itself as one of the industry’s major players.

All of its products are built to last, and all have been designed to beautifully combine function and form: in terms of aesthetics, very little else can come close.

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Cortizo Specifications

Transmittance: Uw ≥ 1.0 (W/m2K)

Acoustic insulation: Rw up to 45 dB

Air permeability: Class 4

Water tightness: Class E1200

Wind resistance: Class CE 2400

Security test: PAS24 passed

Our Customer Reviews

Great Price & Quick Delivery

This company have been amazing and came to our rescue when another company let us down repeatedly over a period of 4 months during our building work. We got a great price, a quick delivery time and the same product but this time with lovely fitters who knew exactly what they were doing. Now we will will have a warm house for christmas HOORAY !! We went for 3 large sliding doors and the quality of the product is excellent . Many thanks to Audrey Cieran and the team I would recommend highly
- Esther Young


Delighted with the product and the service provided by Klosen. The installation team were excellent and very helpful.
- Sara Hyem

Very Happy

We’ve been very happy with the work Klosen recently completed for us. They installed a variety of windows and sliding doors for us on our new build project. All of the information we requested early on was provided promptly and they were great with our architect. Very happy with the end result and the colour they helped us chose.
- Sarah Munton

Senior Architectural Systems

British manufacturer Senior Architectural Systems (SAS) has been at the forefront of the aluminium window industry for over 30 years now. Endlessly innovative, the Doncaster-based manufacturer has a number of firsts to its name.

For example, it was the first to incorporate a polyurethane foam thermal barrier into its windows (delivering huge leaps forward in thermal efficiency) and was the first manufacturer to offer powder-coated finishes with a no-quibble guarantee

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Modern house painted white with wooden panelling and trees behind

Senior Architectural Systems Specifications

Typical sizes:
Width (mm)

Height (mm)
x 1500

Thickness: 28mm – 50mm

Air Permeability: 600 Pa
Water Tightness: 600 Pa
Wind Resistance: 2400 Pa

Residential CEN Standard:
1230 x 1480 28mm Double Glazed Unit: 1.24 W/m2K

Tested to PAS24, BS6375-2 and BS6375-3

Typical sizes:
Width (mm)

Height (mm)
x 1400

Thickness: 28mm – 44mm

Air Permeability: 600 Pa
Water Tightness: 600 Pa
Wind Resistance: 1600 Pa

Residential CEN Standard:
1230 x 1480 28mm Double Glazed Unit: 1.40 W/m2K

Tested to PAS24, BS6375-1, BS6375-2 and BS6375-3


At the beginning of 2021, we embarked on one of our most exciting projects to-date. We were asked to supply and install Cortizo aluminium windows on this one-of-a-kind dream home, inspired by traditional Dutch barns. The build was documented on popular TV series Grand Designs.

So, no matter how ambitious (or straightforward) your project, you can rest assured that the team at Klosen have the skill to take it on.

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Areas We Cover

Based in Market Deeping, Lincolnshire, we cover towns and cities within a 60-mile radius. Popular locations include Peterborough, Bourne, Stamford, Huntingdon and London, but we cover the entirety of Cambridgeshire and Lincolnshire.

Why Choose Klosen?

  • Over 25 years of experience
  • Five-star reputation
  • 10 year guarantee on all work as standard
  • No project is too big or small
  • Experience working on high-profile projects, including a Grand Designs home and the ABBA Arena in London
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Are there any other advantages to choosing aluminium?

Yes – it’s the most sustainable window frame material out there. It’s very easy to recycle, making it ideal for businesses or homeowners who want to prioritise sustainability.

Are triple-glazed aluminium windows as efficient as PVC or wood items?

Traditionally, aluminium is less efficient as the material conducts temperature more than wood or PVC. However, thanks to the technology packed into our windows – like a polyamide thermal break – they’re now extremely efficient.

How much do your windows cost?

Every installation is a little different, so prices will vary depending on your requirements; get in touch today for a quote.

Get in touch with us today to receive your free quotation!