A powerful architecture & Construction theme. Construct your website in the perfect Ratio.
Alienum phaedrum torquatos nec eu, vis detraxit periculis ex, nihil expetendis in mei. Mei an pericula

White Aluminium Windows


Klosen / Aluminium Windows / White Aluminium Windows

Cortizo Flush Casement Windows
New upstairs window in an old brick wall
Heritage Windows


Time to give your home a facelift? Our ultra-modern range of durable, energy-efficient white aluminium windows can do just that, transforming the look of your home and bringing it bang up-to-date.

Our experienced installation team can deliver and fit your windows efficiently, working around your schedule to complete the project without causing you any hassle. Whether you’d like to replace a single window or every single one on your property, we can help.

Plus, we’re so confident in the quality of the products we supply (and our installations) that we include a 10-year warranty with each and every one. So, if you’re looking to invest in aluminium windows and doors and want total peace of mind, look no further.

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

Why Choose White Aluminium Windows?

Aluminium might seem like a left-field option – it’s not as commonly-used as PVC or wood – but it does have a number of key advantages over other materials.

  • Because it won’t rust, rot or go brittle, the window frames can last for a seriously long time
  • Technological advancements (like the polyurethane foam thermal barrier present on Senior Architectural Systems windows) mean they’re highly efficient
  • Aluminium’s strength allows frames manufactured from it to be thinner. Thinner frames means bigger windows and a more airy home
  • Triple-glazed units are available for the ultimate in sound and heat insulation

Our white aluminium windows are no more challenging to install than their PVC or wooden counterparts, and a variety of different designs and finishes are available to suit your taste and your property – whether it’s a new build or a historic home.

White is one of the most popular colours we supply, although we offer black, grey and hundreds of other powder-coated RAL shades too. Take a look at some of our recent installations below.

Brands We Work With

We use our expertise to hand-pick only the very best manufacturers for our installations – which is why we offer Cortizo and Senior Architectural Systems products.

In our experience, they’re impeccably well-engineered and designed to last, and they’re undoubtedly some of the most aesthetically pleasing windows on the market too.

Learn more about each brand below, or download a brochure for further information.

Contact Us
Senior Architectural Systems Logo
Cortizo Logo

10 Year Guarantee

We offer a 10-year guarantee on all 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


Spanish manufacturer Cortizo is one of the world’s most acclaimed suppliers of windows and doors. Its products are designed to allow as much natural light into your property as possible without compromising on energy efficiency.

Did we mention that they’re extremely attractive to look at, too?

Find Out More

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

Based in Doncaster, Senior Architectural Systems has a long history in the industry dating back over 30 years. In that time, it’s risen to prominence as one of the nation’s leading manufacturers, thanks in no small part to its relentless commitment to innovation.

It was the first company to add a polyurethane foam thermal barrier to its windows for heat insulation, for instance, and was the first to offer no-quibble guarantees on its powder coated finishes.

Find Out More
Hambleton Project

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


With many years of experience in our field – and as specialists in aluminium windows – we’ve been asked to work on some exceptional projects over the years. But one that is more memorable than most was our involvement in the construction of this Dutch barn-inspired dream home in South Holland, Lincolnshire.

We supplied and fitted a raft of different Cortizo doors and windows, adding the perfect finishing touch and tying the design together. And the icing on the cake? The house featured on Grand Designs in 2021.

This isn’t the only high-profile project we’ve worked on. We’ve had the privilege of working on many more stunning homes, offices and venues – discover more of our past projects to get inspired.

Find Out More

Areas We Cover

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

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


Does your 10-year guarantee apply to all your white aluminium windows?

Yes, all of our white aluminium window installations come with a 10-year warranty for total peace of mind!

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

Currently, lead times are around five to six weeks from enquiry to installation, although this may vary depending on which product you choose – our team will be able to give you a more precise estimate when you get in touch.

How much does an aluminium window cost to install?

Installation costs are comparable to PVC and wood-framed windows, as the process itself is pretty much the same. The windows themselves are more expensive however, but when you consider their durability and stunning design, you’re still getting excellent value for your money. If you’d like an exact quote, you can request one online.

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