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About Sealed Units

Sealed units, also known as double-glazed units (DGUs), are designed to improve the energy efficiency, comfort, and performance of your windows and doors. Made from two or more panes of glass separated by a spacer bar and sealed together, they create an insulated barrier that helps reduce heat loss and external noise.
At Advance Glass, we supply premium-quality sealed units manufactured to current industry standards, using trusted materials such as Pilkington glass. Each unit is expertly crafted with gas-filled cavities and warm edge spacer bars to deliver superior thermal performance and long-lasting durability.
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Benefits You’ll Notice
Energy Efficient – Helps retain indoor heat and lower energy bills
Noise Reduction – Creates a quieter and more comfortable environment
Condensation Control – Minimises internal moisture build-up
Versatile Specifications – Available in clear, low-E, toughened, laminated, and patterned glass.
Warm Edge Spacers – Available in a range of colours to suit your design

Bespoke Options

All sealed units can be manufactured to your exact requirements, including:
Double or triple glazing
Obscured or decorative glass designs
Argon gas filling for enhanced insulation
Georgian bars or internal duplex systems

Applications

Suitable for both residential and commercial properties, sealed units are ideal for:
Window replacements
New installations
Energy-efficiency upgrades

Types of Glass Available

Break this down clearly to show your expertise:
Low-E Glass – Improves thermal efficiency
Toughened Glass – Extra strength and safety
Laminated Glass – Added security and noise reduction
Obscure Glass – Ideal for bathrooms and privacy
Acoustic Glass – Enhanced sound insulation

Condensation Control

Condensation occurs when warm, moist air comes into contact with a cooler surface, such as glass. This can lead to water droplets forming on the inside of your windows, which may cause discomfort, mould growth, and damage to surrounding materials over time.
Sealed units are designed to significantly reduce condensation by improving the thermal efficiency of your windows. The insulating barrier created between the panes helps keep the inner glass surface warmer, reducing the likelihood of moisture forming.
Using features such as low-E glass, argon gas filling, and warm edge spacer bars, modern sealed units enhance temperature regulation and minimise cold spots around the edges of the glass.
Benefits of Condensation Control
Helps prevent mould and damp issues
Protects window frames and surrounding areas
Improves indoor air quality
Maintains a clearer view with less moisture build-up
Sealed units are designed to minimise condensation; however, it cannot be completely guaranteed.
Craftsmanship you can trust, service you can rely on, and products built to last.

Signs Your Sealed Unit Needs Replacing

This is great for attracting customers who are searching for problems:
Condensation between the glass panes
Foggy or cloudy appearance
Draughts around the window
Increased energy bills
Visible damage or cracks

Repair vs Replacement

When a window is no longer performing as it should, it doesn’t always mean the entire window frame needs to be replaced. In many cases, the issue lies with the sealed unit itself rather than the surrounding frame.
Sealed units can fail over time due to factors such as age, wear and tear, or a breakdown in the seal. This often results in condensation between the panes, a misted appearance, or reduced thermal performance.
If the window frame is still in good condition, replacing just the sealed unit is usually the most practical and cost-effective solution.
Benefits of Replacing the Sealed Unit Only
Lower Cost – Avoids the expense of full window replacement
Less Disruption – Quick and straightforward installation
Improved Efficiency – Restores insulation and energy performance
Enhanced Appearance – Clears misted or fogged glass
Sustainable Option – Reduces waste by keeping existing fram
When Full Replacement May Be Needed
In some cases, a full window replacement may be more suitable, such as when:
The frame is damaged, warped, or rotting
There are structural issues with the window
You are upgrading the entire window system
Our team can assess your windows and advise on the best option based on condition, performance, and budget.
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Windows

Enhance your home or commercial property with our high-quality windows, designed for style, energy efficiency, and durability. Available in a range of materials and finishes, each window is crafted to fit perfectly, providing superior insulation, security, and a modern, polished look.
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Lead Times

Our Lead Times
Standard Glass: 3–4 days
Safety Glass: 5–7 days
Urgent / Priority Orders: Available on request
Please contact us if you need a specific delivery timeframe—we can often accommodate urgent orders.

FAQs

Q: How long do sealed units last?
A: Typically 10–20 years, depending on conditions.
Q: Can you replace just the glass?
A: Yes, in many cases only the sealed unit needs replacing.
Q: Will new units stop condensation?
A: They reduce it but cannot completely guarantee against it.
Q: Do sealed units reduce noise?
A: Yes, the insulating barrier helps reduce external noise.

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