In This Guide
What is Secondary Glazing?
Secondary glazing is an additional window pane installed on the inside of your existing windows. Unlike replacement double glazing, secondary glazing preserves your original windows while creating an insulating air gap that dramatically reduces noise and heat loss.
The system consists of a slim aluminium frame fitted to your existing window reveal, holding a single pane of glass (typically 6mm acoustic glass for noise reduction or 4mm for thermal insulation). The gap between your original window and the secondary glazing - usually 100-150mm - is what provides the exceptional acoustic and thermal performance.
Key Point: Secondary glazing can reduce noise by up to 54dB in suitable configurations - significantly more than standard double glazing which typically achieves 25-30dB reduction.
Key Benefits of Secondary Glazing
Superior Noise Reduction
Reduce external noise by up to 54dB in suitable configurations, making it ideal for properties near busy roads, railways, or flight paths.
Thermal Insulation
Cut heat loss by up to 65% and reduce energy bills by 20-30% annually.
Enhanced Security
Adds an extra barrier against intruders with toughened glass options available.
Preserves Original Windows
Perfect for listed buildings and conservation areas where original windows must be retained.
Types of Secondary Glazing
Horizontal Sliding
Ideal for sash windows. Panels slide horizontally past each other, maintaining the traditional appearance while providing full access for cleaning and ventilation.
Best for: Victorian/Edwardian sash windows
Vertical Sliding
Mirrors the operation of traditional sash windows. Panels slide up and down within the frame, perfect for period properties.
Best for: Listed buildings requiring matching aesthetics
Hinged Casement
Opens like a door, swinging inward on hinges. Provides excellent acoustic sealing and easy access to the original window.
Best for: Casement windows, bedrooms requiring maximum noise reduction
Lift-Out Panels
Fixed panels that can be completely removed when needed. Most cost-effective option with excellent acoustic performance.
Best for: Windows rarely opened, budget-conscious projects
Tilt & Turn
Offers two opening methods - tilting inward at the top for ventilation or fully opening like a casement for cleaning.
Best for: Modern properties, high-rise buildings
Secondary Glazing vs Double Glazing
| Feature | Secondary Glazing | Double Glazing |
|---|---|---|
| Noise Reduction | Up to 54dB (suitable configurations) | Up to 35% (25-30dB) |
| Thermal Performance | Typically reduces heat loss | 70% heat loss reduction |
| Preserves Original Windows | Yes - fully reversible | No - replacement required |
| Listed Building Suitable | Yes | Usually not permitted |
| Installation Time | 2-4 hours per window | Full day per window |
| Cost | 30-50% cheaper | Higher cost |
Installation Process
Survey & Measurement
Our specialist surveyor visits your property to measure windows precisely and discuss your requirements. We assess noise sources, window types, and aesthetic preferences.
Custom Manufacturing
Each secondary glazing unit is manufactured to your exact specifications in our UK workshop. Typical lead time is 2-3 weeks.
Professional Installation
Our trained installers fit the secondary glazing with minimal disruption. Most windows take 2-4 hours each. No structural work is required.
Quality Check & Handover
We demonstrate operation, provide care instructions, and ensure you're completely satisfied before leaving.
Costs & Return on Investment
Secondary glazing costs vary based on window size, type, and glass specification. As a guide:
Small Windows
£300-500
per window
Standard Windows
£500-800
per window
Large/Bay Windows
£800-1500
per window
ROI Insight: Many homeowners find the investment pays for itself over time through energy savings, in addition to the immediate noise reduction benefits. Actual payback period depends on property type, energy prices and usage.
Secondary Glazing for Listed Buildings
Secondary glazing is the approved solution for listed buildings and properties in conservation areas where replacing original windows is not permitted. Key considerations:
- Usually doesn't require Listed Building Consent as it's fully reversible
- Slim profiles available to minimize visual impact
- Heritage-sympathetic finishes match period features
- Can be removed without damage if required in future
Frequently Asked Questions
How long does secondary glazing last?
Quality secondary glazing should last 20-25 years with proper care. The aluminium frames are extremely durable and the glass is easy to replace if ever damaged.
Can I still open my windows?
Yes! Secondary glazing is designed with various opening mechanisms (sliding, hinged, lift-out) to allow full access to your original windows for cleaning and ventilation.
Will it cause condensation?
Properly installed secondary glazing actually reduces condensation by keeping the inner glass surface warmer. We also fit discreet ventilation if needed.
How quickly can you install?
From survey to installation typically takes 2-4 weeks. The installation itself is quick - most standard windows take 2-4 hours each.
Related Resources
Noise Reduction Technical Guide
Understand decibel reduction, acoustic glass specifications, and how to achieve optimal soundproofing.
Cost & Pricing Guide
Transparent pricing information to help you budget for your secondary glazing project.
Secondary Glazing vs Double Glazing
Compare the pros and cons for noise reduction, thermal efficiency, and cost-effectiveness.
Noise Reduction Calculator
Estimate how much noise reduction you can achieve with secondary glazing.
Ready to Get Started?
Book a free survey and get a no-obligation quote for your property.