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Our accredited network of installers offers the highest quality uPVC and aluminium products with excellent customer service.

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Welcome to Sternfenster, one of the UK's largest trade fabricators of uPVC and Aluminium Windows and Doors, established in 1974.

Sternfenster Approved Installer Network

Est. 1974

Established in 1974, Sternfenster has always been a family run business dedicated to delivering high quality products and excellent customer service to the trade and retail industry.

As one of the UK’s largest fabricators of quality products for the fenestration industry, Sternfenster remains committed to its customers and is currently being run by Mike and Simon Parczuk, the sons of the original founders.

Aluminium Factory

45 Years Of Manufacturing

With 40 years of manufacturing uPVC and aluminium windows and doors, we offer one of the most comprehensive portfolios in the UK, including a series of unique windows and doors exclusively from Sternfenster.

StyleLine Windows

Revolutionary Products

As the first fabricator in the UK to acquire a seamless welder from Graf Synergy, Sternfenster has revolutionised the way uPVC windows and doors are produced.

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Aluminium French Doors

Market Leading Profiles

We manufacture a full range of market leading uPVC windows and doors using the Deceuninck 2500 and 2800 series of profile systems. Our aluminium products are manufactured using the high performance profiles from Smart Aluminium.

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Enhance Your Home With Sternfenster Window Systems

Welcoming Customers Since 1974



Sternfenster operates from an 80,000 square metre state of the art factory, supplying high quality windows and doors to installers, builders and homeowners across the UK. Every window and door goes through a rigorous manufacturing process, with only the very best leaving our factory in Lincoln.

StyleLine Doors

In House Paint Spraying

An additional paint spraying facility means that any colour requirement can be met in fast lead times.

Glass Enhancements

In-House Glass Toughening Plant

An in-house toughening plant and two fully automated lines produce over 3,500 glass sealed units every week.

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energy efficient double glazing

Energy Efficient Products

We offer a superb range of energy efficient windows and doors.

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Trade Counters

Local Trade Counter

All of our uPVC and aluminium products are available through our trade counter located alongside our main factory in Lincoln.

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Sternfenster Approved Installer Network

Nationwide Delivery

Sternfenster offer nationwide delivery, with order tracking and an express service if you should need it. Products are supplied quickly and efficiently, without any detriment to quality.

Sternfenster Approved Installer Network

Sternfenster Approved Installers

We have a fully accredited national network of trusted local Sternfenster Approved Installers.

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Residence Collection Windows

Designated Area Managers & Service Engineers

We assign account managers to regions, meaning you get to deal with the same friendly face every time. The same applies for our highly trained service engineers, on hand to assist with any job.

Sternfenster delivery

On Time Deliveries & Appointments

You can trust in our state-of-the-art fleet to deliver your products on time, every time. We go the extra mile to ensure you’re never kept waiting for deliveries or appointments.

Glass Sealed Units

On Site Technical Assistance

We can provide technical guidance on any project, small to large. Simply contact us and we’ll be happy to help.

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Deceuninck 2800 Casement Windows

Excellent Service and Prices

  • We supply industry leading uPVC and aluminium window and door products.
  • With everything in-house, we offer the best quality products at the best prices.
  • We promise high quality products and services to all our trade and retail customers.
  • Sternfenster is 100% committed to delivering the best possible service.
  • Over 140 dedicated employees take pride in our company’s name and reputation.
  • Over 80% of our business is a result of repeat customers and recommendations.

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Request a quote for our aluminium and uPVC windows and doors or view our brochures for more information.

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