How much does vertical sliding secondary glazing cost?

Vertical sliding secondary glazing costs £700-1,400 per window including professional installation. Standard 1200mm x 1800mm sash windows cost £700-1,000, large sash windows £1,000-1,300, and acoustic upgrades add £200-300 to any size.

Is vertical sliding suitable for listed buildings?

Yes, vertical sliding secondary glazing is often the preferred choice for listed buildings and conservation areas. It mimics original sash window operation, is invisible from outside, and typically receives planning approval where other types may not.

Why is vertical sliding more expensive than horizontal sliding?

Vertical sliding requires counterbalance spring systems to hold panels at any position, which adds complexity and cost. The traditional slim aluminium profiles that match period aesthetics are also more expensive to manufacture.

Will vertical sliding damage my original sash windows?

No, vertical sliding secondary glazing mounts to the window frame, not the sash itself. Installation uses discrete fixings on the frame recess. When removed, small screw holes are easily filled, leaving original windows undamaged.

Can both panels slide independently?

Yes, both the upper and lower panels slide independently on their own tracks. This allows top ventilation, bottom ventilation, or both simultaneously - exactly like traditional sash windows.

Secondary Glazing for Sash Windows Cost

£700-1,400

Per window

Perfect

For sash windows

Traditional

Authentic operation

Excellent

Insulation & seal

Secondary Glazing Sash Windows Cost: Standard vs Acoustic

Window Size	Standard Thermal Glass	10.8mm Acoustic Laminate
Small Sash (up to 1000mm × 1200mm)	£700 – £900	£900 – £1,150
Standard Sash (1200mm × 1800mm)	£800 – £1,100	£1,000 – £1,400
Large Sash (1500mm × 2100mm)	£1,000 – £1,400	£1,250 – £1,750

Prices include professional installation. Acoustic laminate adds ~25% for significantly higher noise reduction (up to 54dB).

How It Works

Vertical sliding secondary glazing mimics the operation of traditional sash windows. Two glazed panels slide up and down within their own channels, allowing you to open the window for ventilation while maintaining the period aesthetic.

Features

Both panels slide independently
Counterbalance spring system
Sash locks for security
Brush seals for airtightness

Ideal For

Victorian & Georgian properties
Listed buildings
Conservation areas
Tall, narrow windows

Cost Breakdown

Standard Size (1200mm x 1800mm)£700-1,000

Aluminium frame, 4mm glass, standard finish

Large Size (1500mm x 2400mm)£1,000-1,300

Aluminium frame, 6mm glass, powder-coated finish

Acoustic Version (any size)+£200-300

Upgrade to laminated acoustic glass for maximum noise reduction

Why Choose Vertical Sliding?

Perfect Period Match

Maintains the authentic look and operation of traditional sash windows while adding modern insulation and soundproofing benefits.

• Preserves building character
• Often approved for listed buildings
• Invisible from street view

Practical Ventilation

Unlike fixed panels, you can open for fresh air whenever needed without removing the secondary glazing.

• Top & bottom opening options
• Secure locking positions
• Easy daily operation

Material & Frame Options

Slim Aluminum Frame

Period-appropriate thin sightlines

Standard

25-35mm sightlines match original sash profiles
Available in white, heritage colors, or custom RAL
Conservation area approved designs available

Spiral Balance System

Smooth, effortless operation

Included

Holds panels at any position without props
No weights or pulleys to maintain

Cost Breakdown by Window Height

Sash Window Size	Standard Glass	Acoustic Glass	Installation
Small (1000mm high)	£700-900	£900-1,100	Included
Standard (1500mm high)	£900-1,100	£1,100-1,400	Included
Tall (2000mm+ high)	£1,100-1,400	£1,400-1,800	Included

Vertical vs Horizontal Sliding Comparison

Feature	Vertical Sliding	Horizontal Sliding
Best For	Sash windows, period properties	Wide windows, patios, modern homes
Cost Range	£350-700	£250-550
Aesthetic Match	Perfect for original sash	Modern, patio-door style
Planning/Conservation	Usually approved	May need consideration
Ventilation Position	Top or bottom opening	Side opening

Frequently Asked Questions

Listed Buildings Guide

Secondary glazing for heritage properties

Horizontal Sliding Glazing

Alternative for wider windows

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