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Buying Tips: How To Get the Best Double Glazing?

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Cross section of a double glazed window

Double glazing can lower your energy bills while improving the market value of your home. Double glazed windows also make your home more comfortable by reducing noise levels and eliminating hot and cold spots.

However, new double glazing can represent a major investment. You want to make sure you’re getting the best value for your money, which means buying windows that are energy efficient and durable.

  • Double glazing costs an average of £372-£961 per window, assuming you choose uPVC casement frames.
  • You can expect higher prices if you choose aluminium or timber frames, or if you choose triple glazing.
  • You will also pay more if you choose sash, tilt & turn, bay or bow windows. Their frames are more complex and thus more expensive.
  • An upgrade to double glazing can save you around £235 in annual energy bills, according to the UK Federation of Master Builders.
  • The window industry is very competitive, with more than 3,000 double glazing installers in the UK, and you can get better deals by comparing multiple providers. Click here to compare prices.

We’ve put together a buying guide for double glazing in the UK, to help you make the right investment in your home. Here we discuss the typical costs and savings you can expect and the technical features of double-glazed windows. We also compare five leading glazing providers and their warranty terms.


In this guide you will find:

How much does double glazing cost?

What does double glazing efficiency mean for you?

What types of double glazed windows are there?

Pros and cons of double glazing

Are the any grants available?

Who are the best double glazing installers?

How important are double glazing warranties?


How Much Does Double Glazing Cost?

Double glazing costs are probably your main concern, because you likely have a budget or an idea of what you want to spend. Double-glazed windows are priced based on frame material, glass type, efficiency, size and style. Casement windows with uPVC frames are the most popular option in the UK, and they typically cost £372-£961 each.

Double glazing costs increase significantly if you choose other frame materials. Here are the typical prices of casement windows, considering different frame options:

Casement Frame MaterialTypical Window Cost
UPVC £372 – £961
Aluminium  £744 – £1,147
Timber£1,147 – £1,829
Composite£2,046 – £3,596

These are average prices gathered by the Federation of Master Builders. Your actual costs may be higher or lower depending on the size of your windows, their manufacturer, and the difficulty of your installation. Here is another cost comparison, considering three different window sizes:

Casement Frame Material600mm x 900mm900mm x 1,200mm1,200mm x 1,200mm
uPVC£500£580£620
Aluminium£1,000£1,150£1,250
Timber£1,500£1,700£1,850

What Affects Double Glazing Costs?

You can easily get online quotes to estimate your double glazing costs, but no online quote will be 100% accurate. Fitting costs can represent over 50% of your total budget, and they can only be determined after a visit by a professional window installer. Here are some of the main factors that determine the cost of a double glazing upgrade:

Home Conditions – The difficulty of a window installation depends on your home architecture and current conditions. For example, installing double-glazing on a two-story home is more difficult, which means the labour cost is also higher. The same applies if the wall areas around your windows need repairs before an upgrade.

Location – Most installers will charge more if they must travel to your location, so choosing a nearby installer will likely reduce prices.

Frame – The frame material has a significant impact on double glazing costs, as you can see in the tables above. This applies for windows of all types and sizes.

Glazing – Standard glazing is relatively affordable. However, you can improve energy efficiency by choosing options like argon-filled double glazing and low-E coatings.

Installer – Some double glazing installers charge more than others, either because they offer high-quality windows or because they are a well-known brand. However, make sure you are not paying for an overpriced installation.

The best practice is always comparing offers from multiple double glazing providers. This way, you can get a better idea of the options available, and you can choose high-quality windows with a fair price.

Double Glazing Efficiency: How Much Can You Save?

While cost is an important factor, you are likely considering a window upgrade to save on energy bills. How efficient are double-glazed windows? This depends on many factors like the type of glass, frame design, sealing, etc. You also have the choice of double or triple glazing, and the space between glass panes can be filled with air or inert gases. As you might guess, the price of double glazed windows increases if they have multiple energy efficiency features, but their long-term savings are also higher.

Double Glazing Savings

Double glazing reduces your energy bills by slowing heat gain during summer and heat loss during winter. This means you spend less on space heating and air conditioning throughout the year. Annual savings are relatively small, but they can add up to several thousand pounds during the lifespan of your windows.

  • Double glazing can save around £235 per year, according to the Federation of Master Builders.
  • The average UK home spends around £2,592 in annual energy bills, according to official data.
  • This means double glazing can reduce your annual energy costs by around 9%.

In 2016, the Energy Savings Trust conducted a study that analysed the typical savings achieved when upgrading from single glazing to double glazing. They considered A-rated, B-rated and C-rated windows in five property types. However, UK energy costs increased by 110% between 2016 and 2023, which means the value of the energy saved is also higher:

  • In this period, energy costs for the average UK home increased from £1,236 to £2,592.
  • Natural gas costs in particular increased from £650 to £1,328 per year, which represents a 204% increase.

You can check the original results of the Energy Saving Trust study by clicking on this link. In the following table, we have recalculated these savings to account for the increase in energy costs:

Window Energy Rating Detached Semi detachedMid terraceBungalowMidfloor flat
A rated£240-£310£160-£220£130-£170£110-£150£80-£110
B rated£220-£280£150-£200£120-£160£100-£140£70-£110
C rated£210-£270£150-£190£120-£150£100-£130£70-£100
*The Energy Saving Trust study assumes an upgrade from traditional single-glazed windows to double glazing. Since energy costs have doubled since 2016, we multiplied the savings originally estimated in the study by 2.

Keep in mind that your potential savings also depend on your current window type. You can expect major savings if you are upgrading from double glazing, but savings are more modest if already own double glazing of a lower energy rating.

The energy savings offered by double glazing also depend on the size of your home. A larger home with 4-5 bedrooms uses more energy than a 2-bedroom apartment, but the savings offered by double glazing are also higher.

Understanding the Window Energy Rating (WER)

The Window Energy Rating or WER is an energy efficiency metric that considers many technical features of windows. The WER Rating is a comprehensive performance metric that combines multiple factors, including:

  • U-Value = An indicator of heat loss through the window. Lower U-values indicate less heat loss and a higher energy efficiency.
  • G-Value = An indicator of solar heat gain. Lower G-values indicate that the window is better at blocking sunlight.
  • L-Value = An indicator of air leakage prevention. Lower L-values indicate that the window is airtight and effective at preventing heat loss due to air leaks.

British law mandates that any new windows should be C-rated or better. If your existing windows have a lower WER rating, the law does not force you to upgrade them. However, double glazing is still recommended for its energy efficiency benefits.

The higher the WER rating, the more energy efficient the windows. You can find double glazing with a WER of up to A++ in the UK.

Coatings

Double glazing can include coatings that accomplish several functions, such as improving UV resistance or energy efficiency. Low-emissivity (low-E) coatings can reduce amount of heat that escapes through windows, and they are one of the most common coatings for double glazing.

Making Your Money Back

*While it may seem logical to simply buy the most energy efficient windows you can afford, this isn’t always the best choice. If your primary goal is to reduce your total energy usage and carbon footprint as much as possible, but budget isn’t a large concern, buying A++ windows or triple glazing is a great option. However, you will not likely earn your money back, because the additional energy savings are not enough to account for the higher cost of installation. For this reason, you should carefully consider the total cost of installation, calculate your savings over the lifetime of the windows, and determine if you can earn your money back before making an investment.

Material   C Rated CostA Rated Cost
UPVC  £250-£570£325+
Aluminium   £500-£605£675+
Composite   £575-£625£747+
Wood   £845-£910£1098+

The average double glazing installation in the UK costs £3,000-£5,500, for a detached home with 8-15 windows. However, if you choose windows with a higher WER, you may pay more.

Now that you know how much double glazing is likely to cost to install and how much you can earn back, you can consider your options, decide what you want, and make an informed decision for your house.

Types of Double Glazing Windows

Double glazing windows are available with different styles, frames, and glass, all of which affect the price. Some installers claim to have over 750 different window options, which allows you to pick almost any window to suit your home.

Frames

Most of us think of frames in terms of style and aesthetic, but there are other considerations. For example, as you already learned, some frames are more expensive than others.

Wooden window frameWood/Timber – Wood and timber windows are the most expensive, with prices typically starting out at twice or even triple that of regular uPVC frames. Wood frames are typically treated to prevent rot and mould, but require a high level of regular care to maintain. However, these frames add value to your home, are most appropriate for heritage homes, and typically last more than 25 years with proper care.
uPVC window frameUPVC – uPVC or unplasticized Polyvinyl Chloride frames are affordable, energy efficient, and low maintenance. While the cheapest double glazing option, with proper care, uPVC windows typically last between 10 and 20 years depending on quality, installation, size and brand. These windows add the least value to your home, but do allow you to upgrade to double glazing with a minimum fitting cost. To ensure they last long enough to pay off, get a quality warranty from a reputable installer.
Composite window frameComposite – Composite windows are made of wood chips, like composite doors, which are compressed to offer strength, durability, and low thermal transference. Composite windows are typically priced between the cost of uPVC and wood, but add a similar value to your home as uPVC. Unlike uPVC, composite requires more care, and is susceptible to rot or mould without cleaning.
Aluminum window frameAluminium – Aluminium windows offer durability and strength, with a potential long lifespan, but do have trade-offs. Aluminium frames are the second most expensive option, but offer the lowest energy efficiency. However, they are easy to care for, durable, and will improve energy efficiency when installed with thermal breaks.

Choosing the Best Frame for Your Home

Most British homeowners opt for uPVC windows because they are affordable and energy efficient. However, while a popular choice, they may not be right for you. If you plan to sell your home, want to add to the value of your home, or have traditional windows, you might prefer another option such as wood or aluminium.

In most cases, uPVC windows are a great base option that will last an average of 15 years, and will pay themselves off. If you choose a more expensive frame, your windows may not increase savings enough to reach parity.

Glazing

Glazing can vary a great deal depending on the manufacturer, style, and other features.

Glass Types – In most cases, glass types refer to coatings, the manufacturing method, or the thickness of the glass. Common options include Low E, Reflective, toughened glass, laminated glass, or tinted glass. Each of these finish options is common with double glazing.

Insulating Cushion – Double glazing stops hot and cold air by providing a barrier between your home and the outside. This is most commonly achieved by sandwiching a layer of air or gas between two panes of glass. Standard double glazing features air between the panes. However, you can improve efficiency by choosing an inert gas filling such as argon or xenon gas. While gas-filled windows do cost more, they can make a big difference to energy savings. For example, a standard double glazing window will lose about 17.5% of total heat while an argon filled window will lose about 12.25%.

Cosmetic Options – Many double-glazing installers offer cosmetic features such as leaded glass, stained glass, or other types of decorative glass. You typically pay a premium for these designs, but they do not offer any other benefits.

Frame Styles

While frame materials affect costs, you also need to consider frame styles. Common frame styles include sash, casement, tilt & turn, French, and turn dial. Casement windows are usually the most affordable, while sash frames are more expensive.

Sash – Sash windows feature interlocking frames that open by sliding up, so that the frames overlap. These frames are one of the most expensive options, but offer a very high level of security. While more expensive, some insurance companies offer reduced rates for more secure windows. You can check with yours to see if there is a trade-off for installing sash windows before deciding.

Casement – Casement windows are standard outward turning windows with simple interlocking mechanisms. These windows are the most affordable, but offer high energy efficiency and can feature multi-point locks for security. French windows are simply paired casement windows opening opposite each other.

Tilt & Turn – Tilt and turn windows can open via a standard hinge or can open to tilt out or in. This allows you to open windows slightly to increase airflow without letting in rain or risking the windows to strong winds. While more convenient, these windows offer similar durability and security to casement windows but cost more.

Type of Window Average Cost  
Casement £250-570
Sash £500-1,050
Tilt & Turn £400-675

In most cases, your frame options are a personal choice, which you can choose based on aesthetic and personal preference.

Pros & Cons of Double Glazing

Should you really install double glazing? Double glazing offers a great deal of benefits but surprisingly few cons.

Pros of Double Glazing

  • Adds to home value
  • Reduces heating bills an average of 18%
  • Last 10-25 years or longer
  • Long warranties
  • Reduced carbon footprint
  • Typically low maintenance

Cons of Double Glazing

  • Sealed glazing units are difficult to repair
  • With average costs of installation at £3,000, double glazing is expensive to install

What About Double Glazing Grants or Free Windows?

Unfortunately, there are very few opportunities to qualify for double glazing grants or free windows for the average UK homeowner. While the Green Deal offered assistance with double glazing, this initiative has largely been shut down, and you can no longer get assistance from the government when upgrading windows.

However, if you are in need, are over 60, or are receiving benefits or pension credit you may qualify for several double-glazing grants. These include:

  • Home Repair Assistance Grant
  • Care & Repair
  • Housing Aid for Older People Scheme

Unfortunately, there are no real grants or free double glazing initiatives for regular homeowners or renters.

Secondary Glazing as a Cost Effective Alternative

If your goal is to improve the energy efficiency of your home without a large investment, secondary glazing may be a solution. Secondary glazing involves installing a secondary pane of glass behind your existing glass, giving you some of the benefits of double glazing. However, this method may not be ideal if your frames are old, not compatible with secondary glazing, or your existing windows are improperly sealed.

Best Double Glazing Installers

The top installers in the UK are Anglian, Everest, Safestyle, Weatherseal, and Zenith.

Features Zenith Everest Anglian Safestyle Weatherseal
Guarantee 10-Year10-Year-Lifetime20-year10-Year10-Year
Cost Mid-LowMid-HighLow (Price Match guarantee)Lowest Price GuaranteeMid-Low
Trust Pilot Rating  7.27.87.58.96.2
Products uPVCWood, Aluminium, uPVC,Wood, Aluminium, uPVCuPVC, WooduPVC
Frames 54533


Local Installers vs. Big Name Brands

In most cases, you can get slightly lower prices by going to local installers. However, there is a drawback. Most local installers are unable to offer insurance backed guarantees, which means that if they go out of business, your warranty is void. Large companies can offer better customer service, insurance, and faster installation times as well, which may be worth the additional cost.

Warranties & Guarantees

Most double-glazing windows feature a long warranty, but the extent and coverage of this guarantee will vary depending on the installer. In most cases, you can expect an industry standard 10-year insurance backed guarantee. Some installers like Anglian offer a longer warranty (20 years), but you will see this reflected in the cost of the windows. It is important to check for a workmanship guarantee as well as a product warranty to ensure that your fitting and installation

Saving on Double Glazing

Saving money on double glazing ensures that you can earn your money back and possibly make a profit as well. However, it’s important not to cut costs by choosing inferior materials or windows. Instead, you can save money by doing your research, deciding what you want, comparing quotes to get the best deal, and going into sales meetings informed enough to make a good decision.

If you’re ready to see what a custom quote for your home might like look like, use our free quote comparison service to find the top quotes from local installers. We’ll help you to get the best deal by requesting competitive quotes to get the maximum discount, so you can save as much as 37.5% on your double glazing. Or, if you’re not sure if double glazing is right for you, use our website resources to research your options, find solutions that work for you, and learn enough to make an informed decision.

Written By

Ollie Smith Photo

Ollie Smith

Ollie is the director of Ecopreneurist, with a string of successful publishing brands under his belt, he aims to make the world a better place by showcasing only the best, unbiased and reliable content on the web!

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