30
Apr '25
Composite Doors for Traditional Homes
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Slimline Aluminium Windows
The design of these slimline aluminium windows perfectly captures the look of more traditional window frames, without any of the drawbacks.
The slimline aluminium window frame can be constructed in top and side hung casement and fixed styles. As a result, they have a fantastic range of applications.
Slimline aluminium is the modern choice when it comes to home improvement products. However, they also work as great replacements for older steel windows.
Slimmer frames allow more light into your home, keeping it bright and welcoming.
Slimline Aluminium Windows
Ideal for renovations in heritage and period properties, our slimline aluminium windows are the steel alternative of choice.
Our slimline aluminium windows can achieve a thermal rating to comply with current building regulations.
WER Rating – B. All our aluminium profiles have been sourced from leading manufacturers.
Air, water and wind tested- achieving high performance across all categories.
We offer bespoke colour options, including textured finishes, woodgrain styles and the Sensation range from Smart.
Slimline Aluminium Casement Windows
Wide range of configurations
Smart’s slimline aluminium windows can be applied to a range of different frames, the first of which is the top hung casement model. Casement windows are incredibly popular and can suit modern and traditional properties alike.
Top hung windows work excellently on a pitched roof. This type of window offers excellent home security and weatherproofing across the board, which is further enhanced when they are manufactured with Smart’s slimline aluminium.
Fixed Windows
Cost effective solutions
Fixed window frames are a cost effective way of having these slimline aluminium windows installed, due to the removal of any moving parts. This also means they can be manufactured to just about any size, including larger and smaller frames.
The fixed window frame has no opening mechanisms. Therefore, it also has great commercial appeal as well as domestic. They look excellent in larger buildings and more significant projects. Despite this, they’ll still deliver excellent visual appeal thanks to the slimline design of the Alitherm Heritage 47 profile.
heritage charm
Slimline Aluminium Casement Windows
Wide range of configurations
Smart’s slimline aluminium windows can be applied to a range of different frames, the first of which is the top hung casement model. Casement windows are incredibly popular and can suit modern and traditional properties alike.
Top hung windows work excellently on a pitched roof. This type of window offers excellent home security and weatherproofing across the board, which is further enhanced when they are manufactured with Smart’s slimline aluminium.
Fixed Windows
Cost effective solutions
Fixed window frames are a cost effective way of having these slimline aluminium windows installed, due to the removal of any moving parts. This also means they can be manufactured to just about any size, including larger and smaller frames.
The fixed window frame has no opening mechanisms. Therefore, it also has great commercial appeal as well as domestic. They look excellent in larger buildings and more significant projects. Despite this, they’ll still deliver excellent visual appeal thanks to the slimline design of the Alitherm Heritage 47 profile.
heritage charm
Transform Your Home's Look: Explore Our Window / Door Configurator -
Preview Our Extensive Range of Interior and Exterior Shades With The “Turn Around” Icon.
RAL Colours
Our standard RAL colours are readily stocked and available with quick turnarounds.
White
Agate Grey
Anthracite Grey
Black
Brown
Fir Green Matt
Ivory
Pebble Grey
Purple Red Matt
Signal Grey
Umbra Grey
Violet Blue
Dual Colours
Enjoy interior and exterior customisation, as well as shorter delivery times with our stunning dual colour options.
Premium Colours
Providing exceptional quality and individuality, our non stocked premium colour are available at an additional cost with extended lead times.
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Agate Grey
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Anthracite Grey
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Black
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Brown
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Fir Green Matt
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Ivory
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Pebble Grey
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Purple Red Matt
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Signal Grey
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Umbra Grey
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Violet Blue
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Agate Grey - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Anthracite Grey - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Black - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Brown - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Fir Green Matt - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Ivory - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Pebble Grey - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Purple Red Matt - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Signal Grey - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Umbra Grey -White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Violet Blue - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
White - Ivory
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Any RAL
Unlimited Colours
We provide all our slimline windows in a wide range of different colours, with something to suit every décor. We provide KL colour ranges as well as RAL colour options too. We also offer bespoke colour options including textured finishes, woodgrain styles and the Sensation range from Smart.
Clear
Arctic
Autumn
Casin
Chantilly
Charcoal Sticks
Contora
Cotswold
Digital
Everglade
Flemish
Florielle
Mayflower
Minister
Oak
Pelerine
Reeded
Stippolyte
Sycamore
Taffeta
Tribal
Warwick
Glass Selected:
Clear
Wide Range of Glazing Options
We offer a wide range of stained glass and bevelled glass designs to ensure that our slimline aluminium windows offer a striking, impressive aesthetic. Our comprehensive range of styles allows anybody to find the perfect choice for their property, with ease.
Antique Black
Black
Brilliant Bronze
Gold
Chrome
Grey
Satin Chrome
Solid Gold
White
Antique Black
Black
Brilliant Bronze
Gold
Chrome
Grey
Satin Chrome
Solid Gold
White
Handles & Hardware
Sternfenster offers a broad choice of hardware options with Smart’s slimline windows. We supply a range of authentic options, to better replicate older frames. This includes monkey tail handles and tear drop handles. All are available in a wide range of different colours.
Download Your Brochure
DOWNLOAD BROCHURESTransform Your Home's Look: Explore Our Window / Door Configurator -
Preview Our Extensive Range of Interior and Exterior Shades With The “Turn Around” Icon.
RAL Colours
Our standard RAL colours are readily stocked and available with quick turnarounds.
White
Agate Grey
Anthracite Grey
Black
Brown
Fir Green Matt
Ivory
Pebble Grey
Purple Red Matt
Signal Grey
Umbra Grey
Violet Blue
Dual Colours
Enjoy interior and exterior customisation, as well as shorter delivery times with our stunning dual colour options.
Premium Colours
Providing exceptional quality and individuality, our non stocked premium colour are available at an additional cost with extended lead times.
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Agate Grey
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Anthracite Grey
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Black
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Brown
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Fir Green Matt
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Ivory
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Pebble Grey
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Purple Red Matt
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Signal Grey
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Umbra Grey
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Violet Blue
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Agate Grey - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Anthracite Grey - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Black - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Brown - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Fir Green Matt - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Ivory - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Pebble Grey - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Purple Red Matt - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Signal Grey - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Umbra Grey -White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Violet Blue - White
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
White - Ivory
TURN AROUND
Outside View
*Colour configurations are for illustration purposes only. For detailed colours, contact us today.
Frame Colour Selected:
Any RAL
Unlimited Colours
We provide all our slimline windows in a wide range of different colours, with something to suit every décor. We provide KL colour ranges as well as RAL colour options too. We also offer bespoke colour options including textured finishes, woodgrain styles and the Sensation range from Smart.
Clear
Arctic
Autumn
Casin
Chantilly
Charcoal Sticks
Contora
Cotswold
Digital
Everglade
Flemish
Florielle
Mayflower
Minister
Oak
Pelerine
Reeded
Stippolyte
Sycamore
Taffeta
Tribal
Warwick
Glass Selected:
Clear
Wide Range of Glazing Options
We offer a wide range of stained glass and bevelled glass designs to ensure that our slimline aluminium windows offer a striking, impressive aesthetic. Our comprehensive range of styles allows anybody to find the perfect choice for their property, with ease.
Antique Black
Black
Brilliant Bronze
Gold
Chrome
Grey
Satin Chrome
Solid Gold
White
Antique Black
Black
Brilliant Bronze
Gold
Chrome
Grey
Satin Chrome
Solid Gold
White
Handles & Hardware
Sternfenster offers a broad choice of hardware options with Smart’s slimline windows. We supply a range of authentic options, to better replicate older frames. This includes monkey tail handles and tear drop handles. All are available in a wide range of different colours.
Download Your Brochure
DOWNLOAD BROCHURESWhy not download a brochure to check out our full range of aluminium windows and doors? They’re packed with plenty of additional information, including technical information, detailed colour swatches and photos that can serve as inspiration for your home.
Click through our showroom to explore our products in greater detail
Explore Our Virtual Showroom
Click through our showroom to explore our products in greater detail
Explore Our Virtual Showroom
The Perfect Replacement Window
Our Alitherm Heritage profiles are an excellent choice for homeowners who are struggling to find renovations for their heritage site or older property.
They act as an excellent replacement for outdated steel windows and doors, while also delivering a range of practical benefits. Slimline aluminium is lighter and more robust but still provides the same aesthetics as their steel counterparts.
Impressive Thermal Efficiency
While these slimline aluminium window frames may look to replicate the feel of traditional window frames, they offer brilliant thermal efficiency. Your home’s heat retention will drastically improve.
The Perfect Replacement Window
If you install in areas where period homes are common, then the Alitherm Heritage profile is for you. They are an excellent option for homeowners who are struggling to find renovations for older properties.
They act as an excellent replacement for outdated steel windows and doors, while also delivering a range of practical benefits. Slimline aluminium is lighter and more robust but still provides the same aesthetics as their steel counterparts.
Impressive Thermal Efficiency
These slimline aluminium windows may look to replicate more traditional frames, but they offer brilliant thermal efficiency and heat retention.
Frequently Asked Questions
What advantages do aluminium windows offer?
Aluminium windows typically have a longer lifespan, meaning you could save money on replacements. To save on energy costs, our Smart aluminium windows have thermal break technology to create a barrier between the cold outside climate and the warm air inside.
Do slimline aluminium windows keep in heat?
Despite aluminium formerly being a material that wasn’t great for heat retention, this is no longer the case. Through using modern manufacturing techniques and materials, your home’s heat retention should improve with our slimline aluminium windows.
Who is Sternfenster?
Established in 1974, Sternfenster became one of the UK’s largest trade fabricators of uPVC and aluminium windows and doors. Currently run by Mike and Simon Parczuk, the original founders’ sons, with over 25 employees and hundreds of years combined experience we continue to deliver high-quality products nationally but with the values of a family-run business.
We are proud to have over 50 years of manufacturing at Sternfenster and are fully committed to UK homeowners and offering sustainable products and services wherever possible. Working closely within the trade and retail industry, we offer nationwide delivery across our comprehensive portfolio.
How fast are your lead times?
We offer exceptionally fast lead times as low as five days, without compromising on the quality of our slimline aluminium windows.
Does Sternfenster offer any warranties for their products?
We offer competitive warranties, lead times as fast as five days and outstanding aftercare.
Frequently Asked Questions
Who is Sternfenster?
Established in 1974, Sternfenster became one of the UK’s largest trade fabricators of uPVC and aluminium windows and doors. Currently run by Mike and Simon Parczuk, the original founders’ sons, with over 25 employees and hundreds of years combined experience we continue to deliver high-quality products nationally but with the values of a family-run business.
We are proud to have over 50 years of manufacturing at Sternfenster and are fully committed to UK homeowners and offering sustainable products and services wherever possible. Working closely within the trade and retail industry, we offer nationwide delivery across our comprehensive portfolio.
How do I become a Sternfenster approved installer?
Are you looking for a supplier to help you grow and expand your business? Find out what it takes to join our exclusive club here.
How fast are your lead times?
We offer exceptionally fast lead times as low as five days, without compromising on the quality of our slimline aluminium windows.
Does Sternfenster offer any warranties for their products?
We offer competitive warranties, lead times as fast as five days and outstanding aftercare.
Find Your Approved Installer
Our network of approved installers guarantees you the best service and the highest quality products.
- Postcode
- Name
- Contact Details
Start Selling Sternfenster Today
Get in touch today with enquires for or any of our market leading products. Sell the best with Sternfenster.
Become An Approved Installer
Grow your business with an award winning manufacturer. We’ll support you with materials and expert guidance every step of the way.
Outsource Fabrication To Sternfenster
Looking to outsource for any of your projects? Get started today. We will provide you with expert guidance for your trade success.
