uPVC Box Sash Windows – Timeless Style, Modern Performance

Our uPVC box sash windows combine the charm of traditional timber sash windows with the benefits of modern engineering. Designed to replicate authentic period detailing while delivering excellent energy efficiency, security and low‑maintenance living, they’re the perfect choice for heritage homes, cottages, Victorian terraces and conservation‑style properties.

Every window is crafted with meticulous attention to detail — from near‑invisible joints and elegant sash horns to smooth sliding operation and optional tilt‑in cleaning. You get the classic look you love, without the upkeep of timber.

 Why Choose Our uPVC Box Sash Windows?

Authentic Period Detailing

Inspired by traditional joinery, these sash windows feature beautifully refined design elements that recreate the look of original timber sashes:

• Run-through sash horns for a true heritage appearance

• Deep bottom rail option to mirror Victorian timber profiles

• Slim 37mm midrail available for enhanced authenticity

• Optional ovolo weather bar for a classic sash finish

• Astragal bar layouts to replicate traditional glazing patterns

Smooth Slide & Tilt Operation

Our box sash windows are designed for effortless everyday use. Both sashes slide smoothly for ventilation, and most specifications include a tilt‑in facility, allowing you to clean the exterior glass from inside your home.

• Easy-clean tilt function

• Smooth, reliable sliding action

• Colour‑matched trickle vents available to meet Document F ventilation requirements

Exceptional Thermal Efficiency

With rising energy costs, thermal performance matters. These sash windows are engineered to keep your home warm and comfortable all year round.

• A-rated energy performance

• 1.4 W/m²K U-value as standard

• 1.2 W/m²K thermal upgrade available

• Multi‑chambered frames for insulation

• Argon‑filled double glazing with warm edge spacer bars

Planning & Conservation Friendly

These windows are frequently approved for use in conservation areas thanks to their highly authentic appearance.

• Designed to replicate traditional timber

• Suitable for heritage and period properties

• Increasingly accepted by planning officers

Security & Peace of Mind

Modern security features are built in without compromising the classic look.

• PAS 24 security upgrade available

• Reinforced tilt latches

• Upgraded locking keeps and premium locks

• Optional fire escape facility (0.33m² clear opening)

Hardware Options

Choose from a range of traditional and contemporary hardware styles:

• Lift hooks

• D-handles

• Pole eyes

• Heritage or standard sash knobs

• Travel restrictors for safety

Available in eight finishes, including white, chrome, gold, satin silver, bronze, brushed chrome and antique black.

Colour Options

With 17 standard woodgrain finishes plus bespoke colour-bonding, you can tailor your sash windows to suit any home.

Popular choices include:

• White Grain

• Cream Grain

• Anthracite Grey Grain

• Agate Grey

• Chartwell Green

• Irish Oak, Golden Oak & Rosewood

• Dual-colour options available

Glass Options

Choose the glazing that suits your home:

• Standard double glazing (argon-filled, Low‑E glass)

• Laminated safety glass

• Obscure glass in multiple privacy levels

Styles & Shapes

Our uPVC box sash windows can be customised to suit your property:

• Traditional Georgian or Victorian bar layouts

• Centre bar, margin, asymmetric and swept-head options

• True arched frames available

• Bay and coupled window configurations

Download the Brochure

For full technical details, colour options and specification information, you can download the official Legacy uPVC Sliding Sash Windows brochure below.