Keeping your Surrey home warm and comfortable has never been more important. With energy prices still significantly above pre-2023 and colder winters becoming increasingly common, homeowners across Surrey are looking for ways to reduce heat loss and improve insulation. Upgrading old glazing is one of the most effective places to start.
The UK Government forecasts show that large cuts to household bills are unlikely in the near future. For many Surrey households, replacing old single glazing with modern A rated windows can make a real difference. For the average homeowner this upgrade can save up to £140 on energy bills, as well as enjoying a warmer, quieter home.
As stated by The Glass and Glazing Federation, UK homes were branded ‘the leakiest in Western Europe when it comes to heat loss’ with 98% of the UKs windows falling short of today’s performance standards.
At Elwyns Windows, we’ve been helping local homeowners improve the comfort and efficiency of their properties for over 60 years, serving Surrey and South London from our showrooms in Carshalton, Woldingham and Dulwich. We offer a carefully selected range of energy-efficient windows designed for Surrey’s kerb appeal, conservation requirements and varying property styles.
This guide explains everything you need to know about window energy ratings, what makes a window energy-efficient, and which products offer the best performance for Surrey homes.
What are windows energy ratings?
Window energy ratings (WERs) were established by the British Fenestration Ratings Council, to compare the efficiency of different windows. The system works much like appliance ratings, using a scale from A++ to G, with the highest-performing windows achieving the A and A+ categories.
Unlike older measures that looked at the glass alone, WERs assess the whole window unit, including:
- The frame
- The glazing
- Thermal breaks
- Seals and gaskets
- Overall design
This gives homeowners a more accurate picture of how effectively a window will retain warmth, reduce draughts, and help lower energy bills. Additionally, it is now a requirement for most new windows to meet a minimum of a B or 1.4 W/m²K under UK building regulations (Part L).
Most windows offered by Elwyns exceed these minimum requirements, making them
suitable both for modern builds and for traditional Surrey properties that need a
discreet and sympathetic upgrade.
Key Elements of Energy-Efficient Windows
To understand how windows perform, it’s helpful to know the three core components that make up an energy rating:
1. U-Value (W/m²K)
This measures how easily heat escapes through the window.
Lower = better insulation.
Anything below 1.4 complies with modern building rules, high-performance triple glazing can achieve 0.8 or even lower.
2. Air Leakage (L-Value)
This assesses how much air can infiltrate around the seals.
Lower L-values mean fewer draughts and a warmer home.
3. Solar Gain (G-Value)
This tells you how much warmth from the sun is captured through the glass.
Higher G-values can boost passive solar heat, useful for cold rooms or north-facing spaces.
Understanding these factors helps Surrey homeowners choose the best combination for their property’s orientation, exposure and architectural style.
Evolution Windows: Perfect for Period Homes Across Surrey
Many Surrey homeowners value the classic look of timber windows but want the low maintenance and efficiency of modern materials. Evolution windows offer a premium timber-alternative option that blends authentic styling with cutting-edge performance.
Why Evolution is ideal for Surrey properties:
- 28mm thick double glazing for excellent insulation
- Warm-edge spacer bars to reduce heat loss and condensation
- Optional Argon-filled triple glazing
- A+ WER ratings as standard
o Storm range: A+13
o Flush range: A+11 - U-values as low as 1.3 W/m²K
Evolution is particularly well suited to conservation areas such as Reigate, Dorking, Ewell Village, or parts of Cheam, where the traditional appearance of timber is essential but improved thermal performance is equally important.
Timber Windows: Modern Efficiency with Handcrafted Style
For homeowners who prefer genuine timber frames, Timber Windows offer handmade high-performance wooden that combine craftsmanship with outstanding insulation. Design to complement period homes throughout Surrey, their products achieve impressive levels of energy efficiency.
Why Surrey homeowners choose Timber Windows:
- Argon or Krypton-filled cavities for superior insulation
- Warm edge spacers to minimise heat loss at the edges
- Centre-pane U-value of 1.1 W/m²K , delivering:
▪ Up to 80% improved efficiency over single glazing
▪ Around 45% better performance than ordinary double glazing
Their bespoke timber frames make them perfect for listed buildings, cottages and character homes, particularly in heritage-rich Surrey villages like Limpsfield, Oxted, Chipstead, or Godstone.
Whiteline Windows
Whiteline is known for producing some of the most energy-efficient PVCu windows on the market. Their PlatinumNRG range is especially popular with Surrey households looking for premium insulation without the price tag of timber or timber alternatives.
Whiteline performance highlights:
- Advanced multi-chambered PVCu frame
- A++ energy ratings on selected configurations
- Double and triple glazing options
- Triple glazing with U-values as low as 0.8 W/m²K
- Up to three times more thermal insulation than standard double glazing
- Around 20% better performance than low e-glass, currently required by building regulations
Whiteline windows are an excellent choice if you want to maximise efficiency in a modern home, extension or renovation, ideal for areas such as Sutton, Banstead, Purley, Coulsdon and Epsom.
Why Surrey Homeowners Choose Elwyns
For over six decades, Elwyns has built a reputation as one of Surrey’s most trusted window specialists. Whether you’re restoring a character property, upgrading a family home or building something new, our team is committed to offering:
- Honest, expert guidance
- High-quality installations by experienced fitters
- Trusted premium brands with proven performance
- Showrooms across Surrey, including Carshalton, Woldingham and Dulwich
- Award-winning customer service
We understand Surrey’s homes, from conservation cottages to contemporary houses, and we take pride in helping homeowners choose the perfect windows for comfort, efficiency and style.
If you’re looking for energy-efficient windows in Sutton, Epsom, Carshalton or the surrounding Surrey area, request a free quote from Elwyns today!