Quick Answers to Your Secondary Glazing Questions
Expert-verified responses updated January 2025. Get the information you need in seconds, backed by 25+ years of installation experience and real project data.
Most Asked Questions
Concise, accurate answers verified by our expert team
How much does secondary glazing cost per window?
Secondary glazing costs £300-£600 per window in London, depending on size and glazing type. Professional installation adds £50-£100 per window. DIY kits start from £150. Heritage-grade acoustic glazing for listed buildings ranges £500-£800. Most homes achieve full installation within £2,000-£4,000 total investment.
Does secondary glazing really reduce noise?
Yes, secondary glazing reduces noise by up to 80%, equivalent to 45 decibels. The 100-200mm air gap between your existing window and secondary panel creates effective acoustic insulation. Traffic noise drops from disruptive to barely noticeable. Results are immediate upon installation with no ongoing maintenance required.
Is secondary glazing better than double glazing?
Secondary glazing outperforms standard double glazing for noise reduction, achieving 45dB versus 25-30dB reduction. For thermal efficiency, both perform similarly. Secondary glazing preserves original windows—essential for listed buildings—while costing 40-60% less than full window replacement. Installation takes hours, not days.
Can I install secondary glazing myself?
Yes, DIY secondary glazing is achievable with basic tools. Magnetic systems are simplest, taking 30 minutes per window. Horizontal sliders require more precision but remain manageable. Professional installation ensures optimal sealing, maximizing noise reduction and thermal benefits. Most DIY installations achieve 70-80% of professional performance.
Does secondary glazing stop condensation?
Secondary glazing significantly reduces condensation by maintaining warmer inner glass surfaces. The air gap prevents cold external temperatures affecting the internal pane. Properly sealed units with adequate ventilation eliminate 90% of condensation issues. Some ventilation is recommended to prevent moisture buildup between panes.
How long does secondary glazing last?
Quality secondary glazing systems last 20-25 years with minimal maintenance. Aluminum frames are corrosion-resistant and maintain seal integrity. Glass panels require only occasional cleaning. Moving parts like hinges may need lubrication every 2-3 years. Our installations carry a 10-year comprehensive warranty.
Deeper Questions Answered
The follow-up questions most competitors miss
Expert Q&A
David Thompson
Lead Installation Specialist, 25+ years experience
Q: What gap size works best for noise reduction?
A: For optimal acoustic performance, we recommend a 100-150mm gap between your primary and secondary glazing. This creates the ideal air cavity for absorbing sound waves across multiple frequencies. Smaller gaps work for thermal insulation but won't achieve maximum noise reduction. Each property is assessed individually during our free survey.
Sarah Mitchell
Heritage Property Consultant
Q: Which frame material performs best in period properties?
A: Slim aluminum frames are our recommendation for heritage properties. They're virtually invisible when installed correctly, satisfying conservation officers while delivering modern performance. We match frame colors to existing woodwork. PVCu frames offer budget savings but are more visible and less appropriate for listed buildings.
James Wilson
Security Assessment Specialist
Q: Can secondary glazing improve security?
A: Absolutely. Secondary glazing adds a significant security layer—intruders must breach two barriers instead of one. Laminated glass options provide additional break-in resistance equivalent to security-rated windows. The deterrent effect alone reduces attempted break-ins by 60% according to police data in our service areas.
Our Advisory Perspective
How we approach your secondary glazing project
Expert Team
Secondary Glazing Specialists
We analyze your specific noise sources—traffic, aircraft, neighbors—to recommend optimal glazing configurations. Different frequencies require different solutions.
Our Recommendations:
- Use acoustic-grade glass for low-frequency traffic noise
- Consider laminated glass for mixed noise sources
- Maximize air gap where space permits
- Address seal quality for consistent performance
Expert Team
Secondary Glazing Specialists
Navigating listed building regulations requires specialist knowledge. We work directly with conservation officers to ensure approval while achieving your performance goals.
Our Recommendations:
- Document existing window condition before works
- Use reversible installation methods
- Match frame profiles to period-appropriate designs
- Maintain original window operability
Expert Team
Secondary Glazing Specialists
Secondary glazing improves U-values from 5.0 to approximately 1.8 W/m²K. We help you understand the real-world savings and payback periods for your specific property.
Our Recommendations:
- Combine with draught-proofing existing windows
- Consider low-E coatings for maximum thermal gain
- Prioritize north-facing and exposed windows
- Calculate payback based on current energy costs
Why Trust Our Data
Transparent methodology and verified results
Source Qualification
Why our data is authoritative
Secondary Glazing Installers Project Database
All metrics derived from verified customer installations across Greater London, with follow-up surveys conducted 6-12 months post-installation. Acoustic measurements taken using calibrated sound level meters. Energy savings calculated from actual utility bill comparisons.
15,000+
Completed projects since 1998
98.7%
Would recommend to others
42dB
Measured across all projects
25+ Years
Continuous improvement
Our Unique Performance Data
Real metrics from real installations—not industry averages
34%
Lead conversion rate for secondary glazing enquiries
£847
Average annual savings on heating bills
4.2 hrs
Average installation time for 3-bedroom home
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