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Heritage Aluminium Windows


Klosen / Aluminium Windows / Heritage Aluminium Windows

Heritage Windows with Klosen Van
Heritage Windows at Barn Conversion Site
Heritage Windows


In most older properties, the windows are very likely to be single glazed sash windows made from wood. Owners of listed buildings are required by law to maintain as closely as possible the original look. Heritage Aluminium Windows are suitable replacement windows for period and listed buildings.

Aluminium windows bring modern technology to historic buildings while keeping their original style. With aluminium being a popular choice for many architects, Heritage Windows can both preserve and enhance structures. Upgrades include double glazing and enhanced security and durability.

What are heritage aluminium windows?

If you’re looking to create an elegant industrial look or replace the windows in your period property, Heritage Windows offer a great alternative to traditional steel frames.

Offering charm and period character, these windows combine elegant slimline frames with excellent thermal performance. Fitted with a ‘Polyamide’ thermal break, they keep your property cool in summer and warm in winter. Excellent levels of noise insulation also help your home feel that little more peaceful.

Fantastic choice

The versatile collection from Klosen includes an attractive selection of sash styles with your choice of colour palette frame finishes. We also offer a range of opening mechanisms to suit your preference.

Trusted installer

Klosen is a leading installer of Heritage Style Windows, working with leading brands from across Europe. Download a brochure to find out more about our Heritage Aluminium Windows.

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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

Brands We Work With


We work with Cortizo for high-quality, customisable aluminium and slimline windows and doors. As a valued partner, we are proud to work closely with Cortizo to provide our clients with an exceptional selection of solutions that combine superior craftsmanship with innovative design. Through this collaborative partnership, we consistently deliver products of uncompromising quality that exceed industry standards and satisfy customers.

We have worked across multiple projects in the UK to enhance both looks and practicality. For example, our work in Queens Street, Peterborough ensured that we installed a Cortizo aluminium window resembling steel. This was installed to match the industrial style of the original Crittal windows. We also chose acoustic laminated glass to minimise sound infiltration into the building.

Our team also worked on the Skidby property in Yorkshire, which involved the integration of slimline aluminium glazing into contemporary architecture. This maximised natural light and boosted the property’s functionality.

Download A Brochure
Heritage Windows

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

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

Why Work With Klosen?

With over 25 years in the aluminium window installation business, we’re committed to bringing your property design dreams to life with minimal effort on your part. We partner with top-quality craftsmen and brands to ensure the best possible finish for your facade that you can enjoy for years to come.

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Where We Work

We cover areas across a 60 miles radius from our Lincolnshire-based premises in Market Deeping. We’re ideally located to complete installations in Peterborough and surrounding areas, including Stamford and Huntingdon. We also cover London.

We’ve been trusted to install windows for some big-name clients, including for the ABBA Arena, and we’ve even appeared on Grand Designs.

Our specialist installers are experienced with fitting windows for heritage and new builds. Need to restore your period property? Want to transform your home with the character and timeless appeal of heritage style windows? Get in touch with the expert installers at Klosen today.


Can you install double glazing in listed buildings?

Yes, you can. Our heritage aluminium windows contain high-quality double glazing, meaning they keep the heat in and the cold out. This is a great way to reduce not only your heating bills but also your carbon footprint.

What is a heritage window?

A heritage window is specially designed to mimic the style of traditional period-style windows. They are suitable replacement windows for listed buildings. With Klosen, you have the benefits of modern upgrades, including double-glazing for improved levels of insulation.

What are the benefits of slimline aluminium frames?

Slimline aluminium frames come with plenty of benefits including durability and an elegant design that sits effortlessly among the traditional brick or stonework. With Klosen, the windows also come with a guarantee.

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