If you’re planning to replace your windows, you’ve probably come across the term Window Energy Rating, or WER.
But what does it actually mean? And how do you know which rating is best for your home?
For homeowners in Newcastle and across the UK, understanding WER is key to choosing the right windows—ones that keep your home warmer, lower your energy bills, and reduce your carbon footprint.
At Windows and Doors Newcastle, we help customers navigate window ratings every day. This guide will break down exactly what WER is, how it’s measured, and what to look for when comparing options.
Whether you’re renovating a period home in Jesmond or upgrading a semi in Benton, this is everything you need to know about window energy ratings.
What is a Window Energy Rating?
Window Energy Ratings measure how energy-efficient a window is.
It’s a UK-approved system that scores windows based on how well they:
- Keep heat in (insulation)
- Stop unwanted cold draughts (air leakage)
- Let useful sunlight in (solar gain)
WER is expressed using a familiar letter scale, from A++ (the most efficient) down to G (the least).
The rating includes both the glass and the frame. That means a window’s overall performance depends on the full system—not just the glazing.
Who sets the rating?
Window Energy Ratings are issued and certified by independent bodies like the British Fenestration Rating Council (BFRC), CERTASS, and BSI.
They all follow the same government-approved calculation methods to ensure consistency and reliability.
So if you see a BFRC WER label, it’s based on official testing—not guesswork or manufacturer claims.
What’s included in the WER score?
WER combines three main factors into a single letter grade:
1. Thermal Efficiency (U-value)
This shows how well the window prevents heat escaping. The lower the U-value, the better the insulation.
- Older windows: U-values of 2.0 or higher
- Modern double glazing: Around 1.2–1.4
- Triple glazing: Can drop to 0.8 or lower
2. Solar Gain (G-value)
This measures how much heat the window lets in from the sun. A higher G-value means more free heat from sunlight.
This helps reduce heating bills in winter—but too much can make rooms hot in summer.
3. Air Leakage (L-value)
This indicates how airtight the window is. Less leakage means fewer draughts and better heat retention.
WER balances all three to give you one simple score that reflects overall performance.
What do the WER ratings mean?
Here’s how the WER scale works:
- A++ – Best available. Ultra-high energy efficiency.
- A+ – Excellent performance with lower heat loss.
- A – High performance. Meets modern standards.
- B–C – Acceptable but less efficient.
- D–G – Poor performance. Often older or single-glazed windows.
By law, all new windows in UK homes must meet at least a C rating or have a U-value of 1.6 W/m²K or better.
Most installers today supply A-rated or better as standard.
At Windows and Doors Newcastle, our windows are all A-rated minimum—with A+ and A++ options available for customers who want top-tier efficiency.
How do I check a window’s WER?
Look for the official WER label on the window or product description.
The label will show:
- A letter rating (e.g. A+, B)
- A colour-coded bar (green is best, red is worst)
- The U-value
- The solar gain figure (G-value)
If you’re shopping online or comparing quotes, ask to see the WER certificate or performance spec. Reputable installers should provide this upfront.
Why does WER matter for Newcastle homes?
Living in the North East means cold winters, high winds, and changeable weather. Newcastle homes need windows that can handle it all.
Here’s why WER makes a real difference locally:
- Lower heating bills – A+ rated windows reduce heat loss, saving money every year.
- Fewer draughts – Airtight seals help block cold air and moisture.
- Warmer, more comfortable rooms – Especially in older homes with large windows or bay fronts.
- Higher home value – Buyers look for energy efficiency when comparing properties.
- Better EPC score – New windows can boost your Energy Performance Certificate rating.
We’ve helped many Newcastle customers cut energy waste and feel more comfortable just by upgrading to A+ rated glazing.
Double glazing vs. triple glazing: how do ratings compare?
Both double and triple glazing can achieve high WER scores, depending on the construction.
- A-rated double glazing is often more cost-effective for most homes.
- A++ triple glazing offers the best thermal performance, especially for cold-facing walls or busy roads.
That said, A-rated double glazing is usually more than enough for most properties in Newcastle, unless your home loses a lot of heat or you’re near constant traffic noise.
Do all window types have the same rating?
No. WER can vary depending on the size, style, and frame material.
For example:
- A small casement window may score higher than a large bay.
- uPVC often performs better than aluminium unless the aluminium frame has a thermal break.
- Fixed windows (non-opening) are usually more airtight and can score higher.
That’s why we assess each home individually. At Windows and Doors Newcastle, we’ll match you with the best configuration and frame to meet your energy goals.
How much can I save with better-rated windows?
Savings depend on what you’re replacing.
According to the Energy Saving Trust:
- Replacing single glazing with A-rated double glazing can save up to £145–£155 per year on heating in a semi-detached house.
- Even going from old double glazing to modern A+ units can save £50–£75 per year, depending on usage.
These savings grow over time and can add up significantly over the life of the windows.
Plus, you’ll enjoy better comfort, fewer cold spots, and less outside noise.
Are A+ or A++ rated windows worth it?
If you’re already buying new windows, upgrading from A to A+ or A++ is often a smart move.
It’s a modest extra cost that gives you:
- Better insulation
- Lower long-term energy bills
- Future-proofing against energy price increases
- A selling point for future buyers
We usually recommend A+ rated windows to homeowners looking for a strong balance between price and performance.
For new builds, high-spec projects, or ultra-efficient homes, A++ triple glazed windows are the top choice.
Final thoughts
Understanding Window Energy Ratings is one of the best things you can do before buying new windows.
A high WER means better insulation, fewer draughts, and lower energy bills. It also gives you peace of mind that you’re making a smart investment in your home.
Whether you go with A-rated double glazing or A++ triple glazing, the key is to choose quality products, installed correctly by a trusted local company.
Get expert advice from Windows and Doors Newcastle
If you’re thinking about upgrading your windows, we’re here to help.
We’ll explain the ratings, show you real-world examples, and give you a free quote with no pressure. All our windows meet or exceed the latest energy standards and come with a full guarantee.
Contact Windows and Doors Newcastle today and make your home warmer, greener, and more efficient—starting now.
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