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Triple glazed windows: Is the cost worth it?

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Poorly insulated windows can cost you a fortune. On average, UK homes lose between 10 per cent and 20 per cent of their heat through their windows. This makes triple glazing an option that’s worth looking into. Some manufacturers claim triple glazed windows can cut your heating bills in half. Thanks to their superior insulating properties, they are up to 30 per cent more energy efficient than other types of windows.

Triple glazing also provides superior soundproofing, which is helpful if your home is located in a noisy neighbourhood. And they offer enhanced security, too. But they are more expensive than double glazed windows, which raises the question: are triple glazed windows worth the investment? 

Our windows experts are here to help you figure out the answer to that question. They’ve evaluated the benefits and drawbacks of triple glazing compared with those of double glazing. Their analysis can aid you in deciding whether triple glazing is the right choice for you.

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What is a triple glazed window?

cross section of wood upvc triple glazed window
Just as with double glazing, triple glazing can come in timber, uPVC and aluminium frames to suit specific styles, budgets and maintenance levels. (Adobe)

Triple glazed windows have three panes of glass. Because that’s one more pane than is found in double glazing, triple glazed windows do a better job of keeping homes cool in the summer and warm in the winter. These windows have spacer bars between their panes, which further enhances their insulating properties. They are often made from uPVC, which helps prevent heat loss, though they are also available in other materials. Manufacturers ensure that the panes are fully sealed to prevent condensation.

Triple glazing is versatile and available in a wide range of window styles to suit various architectural and design preferences. Available styles include:

  • Casement windows: many people choose casement windows because they’re simple and suitable for any home design. With triple glazing, these windows offer excellent thermal insulation
  • Sash windows: some people are drawn to the traditional charm of sash windows. With triple glazing, these windows provide enhanced energy efficiency
     
  • Bay and bow windows: some people find bay and bow windows aesthetically pleasing. With triple glazing, these windows’ thermal performance is greatly improved
  • Tilt and turn windows: owners of modern homes often choose tilt and turn windows for their functionality. With triple glazing, these windows offer high energy efficiency while allowing for ventilation and maintaining security
window styles graphic
The different styles of triple glazing windows available (Independent Advisor)

Triple glazed windows: How much do they cost?

Window prices for triple glazing are about 10 per cent to 20 per cent higher than window prices for double glazing. That’s because triple glazed windows weigh more than double glazed windows do and are more complicated to manufacture. As a result, many installers only offer bespoke quotations for triple glazing and make the window units to order. Installation is also more complex. So, these additional costs for triple glazing are not always part of the quote, which is not the case for double glazing. 

Window style and material600mm x 900mm900mm x 1,200mm1,200mm x 1,200mm
uPVC casement£600£680£750
Aluminium casement£1,200£1,370£1,500
Timber casement£1,820£2,050£2,240
The approximate triple glazed windows costs for casement styles.

The benefits of triple glazing

Triple glazed windows have more pros than cons, especially when it comes to energy efficiency. There is some debate about how much more effective triple glazing is at combating noise pollution. But triple glazing is the clear winner at providing higher thermal efficiency and better security and at lowering energy bills. 

More comfortable home temperature

Thermal efficiency, which results in a warmer home, is one of triple glazing’s key benefits. Triple glazed windows have a much better U-value than double glazed windows, which results in an approximate temperature difference of two degrees. A U-value is a measure of thermal efficiency.

Triple glazing generally also has a lower G-value – which is a measure of solar gain – than double glazing does. Solar gain can cause overheating in houses with a large number of windows. So, having a low G-value enables triple glazed windows to keep south- and west-facing rooms cool on hot days.

Glazing typeU-ValueG-Value
Triple glazing0.8 to 0.60.46
Double glazing2.80.78
The U- and G-values of triple and double glazing compared
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What are U-values?

Here are three things you should know about U-values:

  • U-values measure how well windows and other parts of a building transfer heat
  • A high U-value means there’s a lot of heat transfer, and your windows aren’t doing a good job of insulating your home. A low U-value means less heat transfer, better insulation and greater energy efficiency
  • Installing windows with lower U-values can improve your home’s energy efficiency and reduce your carbon footprint
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What are G-values?

Here are two things you should know about G-values:

  • G-values are a measure of how much heat from the sun’s rays enters your home through your windows
  • A high G-value means a lot of the sun’s heat is coming through your windows. A low G-value means the windows are preventing a lot of that heat from coming indoors
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Independent Advisor tip

When shopping for a triple glazed window, look for a low U-value to keep your home warmer in the winter and a low G-value to prevent your home from overheating in the summer.

Energy saving

Triple glazed windows typically score A+ and A++ (the highest value) on window energy-rating schemes. Their sealed design minimises draughts and condensation, and their thermal efficiency reduces cold spots in the home. By comparison, double glazed windows are usually A-rated. 

Thanks to these factors, triple glazing makes households less reliant on central heating systems, which results in substantial savings on energy bills. Some window suppliers claim those savings could be as high as 50 per cent.

Noise reduction 

If you live in a high-traffic area and want to lower the noise levels inside your home, it’s a good idea to upgrade your windows. Both double and triple glazing offer improved soundproofing, particularly if you’re replacing old, poorly fitting single pane windows. The effectiveness of sound insulation generally increases with the size of the gap between the glass panes.

Better security

Each additional pane of toughened glass makes a window more robust and harder to break. So, triple glazed windows are far more secure than single pane windows. And triple glazed windows are typically designed with enhanced safety features, such as Secured by Design (SBD) locking mechanisms.

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Secured by Design

SBD is a UK police initiative that promotes high security standards in building design and construction. The programme aims to reduce burglary and crime rates by incorporating crime-prevention techniques and security specifications. The products and projects it endorses meet stringent security criteria that are intended to ensure safer living environments.

Environmental impact

There’s a high environmental cost for making triple glazed windows because of additional CO2 emissions from manufacturing the third pane of glass and heavier transportation weight for triple glazed units.

However, a Glassonweb.com study of residential glass installations found that CO2 savings over triple glazed windows’ lifetimes outweigh CO2 emissions during their production. The carbon payback period in northern European countries is around 35 months.

living room with lots of windows
Triple glazed windows make homes more energy efficient and are better at regulating temperature. (Adobe)

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Disadvantages of triple glazing

As is the case with every home improvement product, triple glazing has some disadvantages. It’s wise to bear them in mind when you’re deciding whether triple glazed windows are worth the investment.

Higher cost 

As we’ve mentioned, triple glazed windows usually cost at least 10 per cent to 20 per cent more than double glazed ones. You may find this off-putting, especially if you’re planning to replace every window in your home. 

The prices are higher because triple glazing is more technical in design and additional materials are used in the manufacturing process. 

Installation difficulties

Because of triple glazed windows’ extra weight, there is a slightly higher chance of damaging walls during the installation process. But this shouldn’t be an issue with a high-quality professional installer or supplier.

Triple glazing versus double glazing

Choosing between triple glazing and double glazing is a big decision. A lot depends on where your home is located, what your energy-efficiency needs are and how tight your budget is. It’s important to assess quotes from both triple and double glazing suppliers and weigh your options carefully.

Although the initial cost of triple glazing may be higher, it may be worth it in the long run. Your home will have a lower carbon footprint, and your energy bills will be cheaper than they would be if you had chosen double glazing.

Double glazingTriple glazing
Energy rating A+
A++
Warmer home (lower U-value)✓✓✓
Prevents overheating(lower G-value)✓✓
✓✓✓✓
Price ££
£££
Comparison between double and triple glazed windows
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Independent Advisor tip

Combining triple glazing in colder rooms with double glazing in warmer rooms could be a great way to get the best of both worlds. For instance, double glazing would be a good addition to south- and west-facing rooms, which are prone to overheating. Triple glazing could be installed in north- and east-facing rooms, which can be chilly and have lower light levels. Triple glazing does a better job of retaining internal room temperatures.

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Is triple glazing worth it?

To decide if triple glazing is worth it for your home, use our quote form to obtain quotes on both triple and double glazed units in the same styles and materials.

If you opt for triple glazing, you’ll get superior insulation, which will help keep your home warm in winter and cool in summer. You’ll save energy. You’ll enjoy added peace and quiet because triple glazing excels in reducing outside noise. And you’ll gain an additional layer of security thanks to the extra pane of glass in each window.

However, your initial investment will be higher than it would have been if you had chosen double glazing. And although triple glazing delivers long-term benefits, especially in colder climates, the time it takes to recoup the investment through energy savings is longer. 

Ultimately, triple glazing is a substantial upgrade for enhancing home comfort and energy efficiency. But its value is maximised in environments where its advantages can be fully realised.

Does triple glazing add to the value of your home?

Triple glazing can definitely add value to your home. Triple glazed windows make your property more energy efficient and lower your heating costs, which is something potential purchasers will appreciate if you decide to sell it. The improved security and superior sound insulation that triple glazing offers also add to your home’s overall comfort and increase its resale value. 

How can I find the best deals on triple glazing?

To find the best deals on triple glazing, fill out our quote form and compare quotes from several of our trusted suppliers. They often offer seasonal discounts or promotions on triple glazing if you’re already considering installing double glazed windows.

Triple glazing FAQs

There are no specific triple glazed windows grants. But you can apply to other government schemes that may enable you to boost your home’s energy efficiency with other home improvements, such as window installations and upgrades.

Triple glazed windows are designed for durability and longevity and typically last between 20 and 35 years, depending on what material they’re made with. While uPVC triple glazed windows might last for 15 to 20 years, carefully maintained wooden triple glazed windows could last for up to 60 years. When properly installed and maintained, high-quality triple glazed windows can last even longer than that. You can extend their lifespan by cleaning them regularly, keeping the sealant repaired and making sure the window frames are in good condition.

Investing in windows from reputable manufacturers and hiring highly professional installers are key steps to ensuring your triple glazed windows perform efficiently and last as long as possible.

Yes, triple glazed windows are available in a wide range of colours, so you can choose options that harmonise with your home’s exterior colour scheme and enhance its appearance. The choices include traditional white windows, contemporary anthracite grey windows and sage green windows. There are even dual colour options with frames that are one hue on your home’s exterior and another inside your rooms. Manufacturers often offer custom colour services that allow you to achieve the exact look you desire.

Triple glazed windows can be fitted with various types of glass to meet different needs. Low-emissivity glass minimises heat loss, toughened safety glass offers added security and noise-reducing acoustic glass reduces sound transmission. 

Additionally, self-cleaning glass uses sunlight and rain to keep windows clear, and decorative glass beautifies your property.

The Part L Building Regulations, which took effect in June 2022, require new builds to have windows installed with a 1.2W/m²K U-value to comply with the 2023 Future Homes Standard. And replacement windows must have a maximum U-value of 1.4W/m²K or a B for their window energy rating. 

In January 2023, the Scottish government announced plans to introduce a standard for all new build housing to meet an equivalent of the Passivhaus standard. The official report doesn’t specify what the Scottish standards are. But Passivhaus builds often use triple glazing to achieve the low U-values required for certification.

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Katharine Allison

Energy Saving Writer

As Independent Advisor’s energy saving expert, Katharine, a keen advocate for sustainability, is an authority on solar panels, double glazing, and cutting-edge renewable energy technologies. Her dedication merges with a commitment to enlighten and steer readers toward embracing eco-friendly solutions and the latest trends in sustainability.

With over 10 years of experience, she has worked with some of the UK’s leading companies and publications, including the Federation of Master Builders, Architectural Digest, and Denon Construction. 

Katharine is particularly passionate about consumer causes and animal welfare and has art, philosophy, and psychology degrees. She lives with her sled dogs in East Sussex.