Investing in double glazing units is one of the most effective ways to improve your home’s insulation, reduce energy bills, and enhance comfort. However, not all double glazing is created equal. Choosing the right units can make a significant difference in heat retention, noise reduction, and long-term savings.
In this guide, we’ll explore the key factors that determine energy efficiency in double glazing and help you make the best choice for your home.
What Makes Double Glazing Units Energy Efficient?
The efficiency of double glazing units depends on several factors, including:
- The type of glass used
- Low-emissivity (Low-E) coatings
- The gas filling between the panes
- The quality of window seals and frames
Understanding these components will help you choose the best double glazing units for maximum thermal efficiency.
1. Choosing the Right Glass for Energy Efficiency
The type of glass used in double glazing units affects insulation and performance.
Low-E Glass (Low-Emissivity Glass)
- Has a special coating that reflects heat back into the room
- Reduces heat loss while allowing natural light to pass through
- A must-have feature for energy-efficient double glazing
Toughened or Laminated Glass
- Improves security and durability
- Helps reduce noise pollution, ideal for busy areas
- Provides better insulation compared to standard glass
Self-Cleaning & Solar Control Glass
- Self-cleaning glass reduces maintenance by breaking down dirt
- Solar control glass prevents excessive heat from entering, perfect for south-facing windows
For maximum energy efficiency, opt for Low-E coated toughened glass combined with an insulating gas fill.
2. Understanding Gas-Filled Double Glazing Units
The space between the two panes in double glazing units is often filled with insulating gas. The most common options are:
- Argon gas – Improves insulation by reducing heat transfer
- Krypton gas – Offers superior insulation, ideal for triple glazing
- Xenon gas – The most effective but also the most expensive option
For most homeowners, argon-filled double glazing provides the best balance between performance and cost-effectiveness.
3. Checking the Window Frame Material
While the double glazing units themselves are crucial, the frame also plays a role in energy efficiency. Common materials include:
- uPVC frames – Affordable, durable, and good insulation properties
- Aluminium frames – Modern and stylish but require a thermal break to reduce heat loss
- Timber frames – Excellent insulation but require regular maintenance
For the best energy efficiency, opt for multi-chambered uPVC frames with thermal breaks.
4. Ensuring High-Quality Window Seals
Poor-quality seals can lead to draughts and condensation inside double glazing units, reducing their effectiveness. Ensure your windows have:
- Durable rubber seals to prevent air leaks
- Warm edge spacers to minimise heat loss at the glass edges
- Properly fitted frames to avoid gaps and energy loss
5. Understanding Energy Ratings for Double Glazing Units
In the UK, double glazing units are rated for energy efficiency using the Window Energy Rating (WER) system.
- A++ Rated Windows – The most energy-efficient, providing excellent insulation
- A Rated Windows – Still highly efficient, commonly recommended for homes
- B & C Rated Windows – Less effective but better than single glazing
For the best energy efficiency, choose A-rated or A++ units.
6. The Benefits of Energy-Efficient Double Glazing Units
By choosing high-quality, energy-efficient double glazing units, you can expect:
- Lower energy bills – Reduce heat loss and cut heating costs
- Reduced condensation – Prevent misting and moisture build-up
- Improved home comfort – Keep rooms warmer in winter and cooler in summer
- Better noise insulation – Block out external sounds for a quieter home
Upgrade to the Best Double Glazing Units with Cove Glass
At Cove Glass, we supply and install high-quality, energy-efficient units designed to enhance your home’s insulation, security, and aesthetics. Whether you’re replacing old windows or upgrading to the latest technology, our experts can help.
📞 Call us: 01252 318787
📧 Email us: sales@coveglass.co.uk
🔗 Learn more: Double Glazing Units
Frequently Asked Questions (FAQs)
Q1: How much do energy-efficient double glazing units cost?
A1: The cost depends on the glass type, gas filling, and frame material. On average, A-rated double glazing units start from £250 per window, while A++ rated windows can cost £400 or more.
Q2: How long do double glazing units last?
A2: High-quality units can last 20-30 years, depending on maintenance and exposure to weather conditions.
Q3: Can I replace just the glass in my units?
A3: Yes. If your frames are in good condition, you can replace only the sealed glass unit instead of the entire window, which is a cost-effective way to restore insulation.