Fixed Secondary Glazing
Most cost-effective solution for maximum insulation
Per window
Thermal performance
Cheaper than opening
Permanent seal
What Is Fixed Secondary Glazing?
Fixed secondary glazing is a non-opening panel of glass or acrylic permanently sealed to the interior window frame. Unlike hinged or sliding systems, fixed panels don't open, making them the simplest and most cost-effective secondary glazing option available.
This type works exceptionally well for windows that you rarely or never need to open - such as hallway windows, stairwell windows, or decorative front-facing windows. The permanent seal provides superior thermal and acoustic performance compared to opening systems.
Cost Breakdown by Window Size
Bathroom, toilet windows
inc. installation
Typical bedroom window
inc. installation
Living room window
inc. installation
Key Benefits of Fixed Secondary Glazing
Lowest Cost Option
30-40% cheaper than opening systems because there are no moving parts, hinges, or complex hardware. Simple aluminum or uPVC frame with sealed glazing panel.
Best Thermal Performance
Permanent compression seal eliminates air leaks. Can achieve U-values as low as 1.6 W/m²K - better than many opening systems because there are no gaps.
Superior Acoustic Insulation
Continuous seal provides excellent noise reduction - up to 35-45dB with 6mm glass. No gaps means no sound leakage around edges or hinges.
Enhanced Security
Can't be opened from outside. Permanently fixed panels add extra security layer. Popular for street-facing windows in urban areas.
When to Choose Fixed Secondary Glazing
Ideal Situations
- Windows you never open: Hallway windows, stairwell windows, decorative front bay windows
- High noise areas: Main road traffic, railway lines, airports - fixed panels provide best acoustic performance
- Maximum energy efficiency: When thermal performance is top priority over ventilation access
- Budget-conscious projects: Getting most windows covered with limited budget
- Security enhancement: Ground floor street-facing windows needing extra security
Not Suitable For
- Fire escape windows: Building regulations require openable windows for emergency exit routes
- Sole ventilation source: Bathrooms and kitchens need access to windows for ventilation
- Window cleaning access: If you need to clean exterior glass regularly, consider lift-out or hinged
- Properties requiring flexibility: Rental properties might benefit from removable systems
Material Options for Fixed Glazing
4mm GlassMost Popular
Best balance of cost and performance. Crystal clear, scratch-resistant, and long lifespan. Ideal for most residential applications.
6mm Acoustic GlassPremium
Maximum noise reduction for busy roads, flight paths, or railways. Heavier weight provides superior sound dampening. Best thermal performance.
Acrylic (Perspex)Budget
Lightweight and impact-resistant. Good for large windows or where weight is a concern. Can scratch more easily than glass but much more affordable.
Installation Process
Measure Window Recess
Measure the internal window frame dimensions precisely. Fixed panels require accurate measurements as there's no adjustment after manufacture. Most installers measure twice to ensure perfect fit.
Install Aluminum Frame
Screw the aluminum or uPVC frame to the window reveal or existing frame. This takes 20-30 minutes per window. Frame is leveled and squared using shims if needed.
Seal Glazing Panel
Glass or acrylic panel is permanently sealed into the frame using compression gaskets or glazing tape. Creates airtight seal. Some installers use silicone for additional weatherproofing.
Final Sealing & Testing
All edges sealed and checked for drafts. Professional installers will test thermal and acoustic performance. Cleanup and protection removed. Takes 10-15 minutes per window.
Typical Installation Time
Single window: 45-60 minutes | Full house (10 windows): 1 full day | Zero building work required
Comparison: Fixed vs Opening Systems
| Feature | Fixed | Hinged/Sliding |
|---|---|---|
| Cost per window | £150-400 | £280-700 |
| Thermal performance | Good | |
| Acoustic performance | Good | |
| Window access | ||
| Ventilation | ||
| Maintenance | Requires servicing | |
| Best for | Rarely-opened windows | Regular access needed |
Frequently Asked Questions
Can fixed panels be removed if needed?
While designed to be permanent, fixed panels can be removed by unscrewing the frame. However, this defeats the purpose and may damage the seal. For temporary installations, consider lift-out or magnetic panels instead.
How do I clean the window behind the panel?
Clean the primary window thoroughly before installation. Once installed, the gap between panels stays remarkably clean as it's sealed from dust and dirt. Most homeowners report no cleaning needed for years. External window cleaning access remains unchanged.
Is fixed glazing suitable for listed buildings?
Yes, fixed secondary glazing is often preferred for listed buildings because it's fully reversible and doesn't alter the primary window. Many conservation officers approve fixed panels with slim-profile frames that maintain period aesthetics. Always check with local conservation officer first.
What's the lifespan of fixed secondary glazing?
Glass panels last 25-40+ years with minimal maintenance. Acrylic panels typically last 15-25 years. Aluminum frames last 30+ years. The simplicity of fixed systems (no moving parts) means longer lifespan than opening systems.
Can I install fixed secondary glazing myself?
DIY installation is possible with good DIY skills. You'll need: drill, level, measuring tape, and glazing tools. However, professional installation costs only £50-100 per window and ensures perfect fit and seal. Most homeowners choose professional installation for best results.
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