The right windows can change how your home feels all year round. They hold onto warmth on cold winter evenings, keep draughts at bay and help bring down your heating bills. The good news is that once you know what to look for, choosing energy efficient windows is easy.
In short, look for an A energy rating or above, quality double or triple glazing and well-insulated frames, all fitted by a trusted installer. It’s the whole window working together that keeps the warmth in and the draughts out.
In this guide, we’ll walk you through the features that make the biggest difference, from the glass and frames to energy ratings, so you can choose your new windows with confidence.
Key takeaways
- An A energy rating or above is the easiest way to spot an efficient window, and every window we fit is A-rated as standard.
- The glass, frame and seals work as a team, so it pays to look at the whole window.
- Double glazing suits most homes, while triple glazing is worth considering if your home is exposed or on a busy road.
- Careful installation by a trusted company helps your new windows perform as they should.
What are energy efficient windows?
Energy efficient windows are designed to reduce heat transfer between the inside and outside of your home. They use insulated glass units, thermally efficient frames and tight seals to keep warmth in during the colder months, cut draughts and lower the energy use in your home.
What makes a window energy efficient?
The glass
Most of a window is glass, so this is where much heat can be lost. Our windows use premier glazing from industry leader Planitherm, which has an invisible coating on the surface of the glass that reflects heat back into the room. You still get plenty of natural light, and your furnishings are better protected from fading UV rays.
What’s between the panes
Inside a sealed glass unit, the gap between the panes of glass is filled with an inert gas such as argon, which is denser than air and slows heat escaping. Around the edges, warm edge spacers hold the glass apart and help stop cold spots and condensation forming along the bottom of the window.
Seals and locks
Ever felt a cold whistle of air around an old window on a windy night? That’s air leakage and it can undo the good work of even the best glass.
Our windows are secured with multi-point locking, so when you close the window it sits snugly in the frame. That keeps the warmth in and the draughts out whilst giving you extra peace of mind on security too.
Double vs triple glazing: which should you choose?
| Double glazing | Triple glazing | |
| Panes of glass | Two | Three |
| Keeping warmth in | Very good, A-rated as standard | Our best, with an extra pane for even less heat loss |
| Cost | The more affordable choice | Around 20% more expensive than double glazing |
| Keeping noise out | Good, with acoustic glass available for extra quiet | Better, as the extra pane blocks more outside noise |
| Best for | Most homes | Homes on busy roads, in exposed spots or with rooms that feel the cold |
For most homes, A-rated double glazing does a brilliant job. Triple glazing comes into its own if your home takes the full force of a British winter, perhaps on an exposed hillside, or sits next to a busy road.
The Energy Saving Trust says triple glazing costs around 20% more than double glazing, but the extra warmth, peace and quiet and security can make it worth it.
Energy ratings: what do they mean for you?
Windows carry energy ratings just like your fridge or washing machine, on a scale from A++ to E. The British Fenestration Rating Council (BFRC) rates the whole window, looking at how much heat it lets out, how draughty it is and how much warmth it lets in from the sun.
The simple rule is that the closer a window is to A++, the better it is at keeping your home warm. Every window we fit is A-rated as standard and our Residence 7 and Residence 9 windows go a step further with an A+ rating.
What is a U-value?
You might also see a U-value on a quote. It simply shows how easily heat escapes through a window, and the lower the number, the warmer your home stays.
Building regulations say replacement windows need a U-value of 1.4 or lower. With triple glazing, our uPVC and aluminium windows can reach as low as 0.8, so they keep in far more heat than the minimum required.
Choosing the right frame material
- uPVC: inside our uPVC frames are between five and nine hollow chambers. Think of them like layers in a winter coat: the more there are, the longer your home holds onto its warmth. They won’t warp, crack or split.
- Aluminium: aluminium is strong but lets heat pass through easily on its own. That’s why our aluminium frames have a thermal break built in, a strip of insulating material that separates the cold outside from the warm inside. Slim frames also mean bigger glass panes.
- Timber alternative windows: if you live in a period home, our flush sash and sliding sash windows give you a traditional look with the warmth of modern uPVC.
The benefits of upgrading your windows
If your windows are more than 20 years old, upgrading could make a real difference. U-values have come down by over 30% in the last 20 years, so old double glazing often lets out much more heat than new windows.
The benefits include:
- Lower energy bills: the Energy Saving Trust estimates that replacing single glazing with A-rated double glazing saves homeowners around £85 a year
- A smaller carbon footprint: the same upgrade could cut carbon dioxide emissions by around 290kg a year
- Warmer, cosier rooms: you can sit by the window on a winter’s evening without reaching for a blanket
- A quieter home: less traffic and street noise, especially with triple glazing or acoustic glass
Energy efficient windows from The Nottingham Window Company
Truly energy efficient windows combine an A rating or above, high-quality glazing, well-insulated frames and expert installation. At The Nottingham Window Company, every window we supply meets these standards.
We’re a family-owned business and have been fitting windows across Nottingham, Derby, Leicester and the wider East Midlands for over 20 years. All our products are quality assured by CERTASS and come with QANW Insurance Backed Warranties and a lifetime guarantee.
If you’d like friendly, honest advice on the most energy efficient windows for your home, book a free consultation, call our team on 0115 866 0066 or pop into our showroom at 36b High Street, Hucknall, to see our windows for yourself.
Frequently asked questions
Is triple glazing worth it?
For homes that feel the cold or sit near a busy road, triple glazing is a great choice. That extra pane of glass keeps more warmth in and more noise out. For most homes, though, A-rated double glazing gives excellent results for a lower cost.
Are aluminium windows energy efficient?
Yes. Modern aluminium windows are very different from the cold, draughty frames of the past. Ours are A-rated and have a thermal break inside the frame, which stops the cold outside from reaching the warmth inside.
How long do energy efficient windows last?
Our uPVC windows are designed to last at least 30 years maintenance-free, while our aluminium windows have a life expectancy of around 45 years. Every window we fit also comes with a lifetime guarantee.
What does an A-rated window mean?
It means your window sits near the top of the UK energy rating scale, which runs from A++ to E. In practice, it’s a window that keeps your home warm, cuts draughts and helps lower your heating bills. Every window we fit is A-rated as standard.