“Extreme” is the most fitting word to describe the industry leading replacement UPVC windows offered by TWC.

Our Extreme window range delivers extreme performance in every respect, particularly when it comes to thermal efficiency and security, and they can even outperform standard A-rated windows, considered by many to be the best window option on the market.

Huge breakthroughs have been made by our engineers and designers to ensure the extreme range expertly retains internal warmth and subsequently reduces the resilience householders have on their heating systems. If you’re currently living with older and draughty windows, you’ll be astounded at the difference our replacement windows will make to your home.

Extreme UPVC Windows

Extreme UPVC windows are also intelligent enough to draw in the heat of the sun like a magnetic force, helping you to reduce your energy bills. Join the growing number of Wiltshire and Oxfordshire homeowners opting for extreme window quality.

In addition to their high-quality performance, there is no exaggeration on our part when we say that we have hundreds of shades, textures and wood effects you can pick from.

Grey Extreme UPVC Windows
Extreme UPVC Windows


Many of our most popular window designs are available in UPVC, including our casement windows, tilt & turn windows, sliding sash windows and bay & bow windows.

Cream UPVC Cottage Windows


Our casement windows are a timeless classic. Combined with the most classic of the materials, UPVC, they truly are a window design for the ages.

UPVC Tilt & Turn Windows


Nothing beats a UPVC tilt & turn window for versatility. With flexible wide openings, they allow you to get the perfect amount of ventilation into your Wiltshire or Oxfordshire home.

UPVC Sash Windows


We have brought the traditional style of the sliding sash window to the 21st Century by manufacturing the design from UPVC.

Do your windows have EXTREME protection?

Security must never be overlooked - TWC prioritises it when manufacturing our windows. Our EXTREME range is security-focused, with no less than 11 visible locking points being present within our window designs, making them 3 times more secure than most windows.

  • EXTREME enhanced security with centre VAULTBOLT and multi cam locking technology.
  • EXTREME enhanced durability with UNIQUE superglide gearbox ensures smooth operation.
  • EXTREME enhanced COMPRESSION and acoustics with interlocking hinge bolts and optimum weatherseals.
Casement Windows

Herculean Hinge

These heavy duty and highly engineered hinges offer increased load bearing. Featuring anti-crowbar technology, they promise a lifetime of performance.

Extreme Locking

With up to 9 locking points and two high compression hinge bolts, you get 360-degree solidity. Upgrade to Secured by Design if you want the lock to meet the Police-approved standard and be further assured of safety.

Extreme Frame

An EXTREME frame is made up of a total of 14 chambers (combined sash and frame) to deliver exceptional thermal performance. This also makes it twist and age-resistant, stopping your windows from ever losing their appearance.

Extreme Weather Seal

Get twice the standard coverage thanks to high elasticity and dual density. Defence against the elements and excess noise comes courtesy of long-lasting airtight protection.

Ultimate Glass

Our next generation glass, with its ultra-clear outer pane and super soft coat inner pane, will give you the best in energy efficiency and the most spectacular view.

Extreme Handles

The robustness of an EXTREME handle is unrivalled and the handles can be finished in a colour that suits your windows most.
Make your energy costs so much cheaper...

The worldwide energy crisis is hitting homeowners the hardest and it makes it crucial that your property is energy efficient. It will be once you have your old windows removed and exchanged for our EXTREME UPVC windows.

Far less heat will escape from the place and you won’t feel the draughts that previously filled it. They will make it warmer and at the same time, let you reduce your energy usage.

White UPVC Windows
Oak Envisage Flush Windows
White UPVC Windows


Once you know the window style that you want, it needs to be customised for your home. This involves selecting a suitable colour, glazing and hardware so that they’re in character with the building.

A definitive suite of glazing options, including privacy glazing...

We don’t have to point out how integral glass is to the overall window design. Your choice of glass should be dictated by what you want it to actually do – if it’s a reduction in energy costs you seek, our high performance next generation glass is probably your best option. Speak to our team to select a glass type that meets your objectives.

Handles crafted with care…

When you look at and touch our traditional and contemporary handles, you gain an appreciation for how much time and effort has been put into making them by our craftspeople.

You can trust the locking system in the handles to stop your windows being forced open when locked.


Simply fill in your details for your free, no obligation quotation, and click "Get Quote"