How much does double glazing cost, and what can it save you?

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Double glazing windows have become an aspiration for homeowners in recent years, but how much does double glazing cost? Many people assume that it’s out of reach financially, but double glazing can actually save you money in areas ranging from heating bills to maintenance costs, and could be a worthwhile investment.

This article explains everything you need to know about double glazing, including how it works, its benefits, how to find a reliable glazier, how much it costs, and the savings you can make in the long run.

What are double glazing windows, and how do they work?

Double glazing is a type of window that consists of two panes of glass with a space in between. This space is typically filled with air or argon gas, creating an insulating layer that helps to keep your home warm during the colder months and keep heat out when the temperature is warmer.

As a result, double-glazed windows are more energy-efficient than single-pane windows. They also reduce noise pollution, as the trapped air acts as a sound barrier.

When was double glazing introduced?

Double-glazed windows were first introduced in the 1930s in an attempt to reduce noise pollution from trains. However, it wasn’t until the 1970s that double glazing became popular in homes as a way to improve energy efficiency.

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How much does double glazing cost?

The cost of double glazing will depend on the size of your property and the number of windows you need. For example, a small flat with four windows might cost between £600 and £2,400, while a detached property with 20 windows could range from £3,000 to £12,000.

Factors that affect the cost include:

• Window size
• Window style
• Frame material
• Glass quality
• Energy rating
• Installer rates

The table below outlines costs per window for a range of window styles and frame materials:

Window style	uPVC	Timber	Aluminium	Steel
Casement	£560–610	£600–650	£650–700	£720–770
Sash	£650–700	£690–740	£750–800	£830–880
Tilt and turn	£760–810	£810–960	£880–930	£970–1,020
Dual turn	£820–850	£870–920	£940–990	£1,050–1,100
Bay	£1,510–1,560	£1,620–1,570	£1,710–1,760	£1,940–1,990

The prices above relate to a full window replacement with double glazing. If you just need the double glazing unit replaced, then you might pay as little as £100. While this is the cheaper option, professionals advise against it, as the older frames will still let noise and cold air into your home.

Types of glass

The type of glass you choose will impact the cost of double glazing, but each type offers certain benefits that are worth considering.

Float glass

Float or annealed glass is the most basic type of double glazing and is also the cheapest. It’s strong and extremely difficult to break, so it’s useful in low-cost double-glazed units. However, if this glass breaks, the shards are very jagged, which can be dangerous.

Toughened glass

Toughened or tempered glass is actually three times more robust than float glass, making it almost impossible to break. In contrast to float glass, this type of glass breaks into crystal cubes that are less likely to cause injury.

Toughened glass is made by being heated to a temperature of around 700°C. This is then followed by applying blasts of cold air on both sides—a method that enables the outer layers to cool down quicker than the core, which causes the glass to solidify and strengthen.

Laminated glass

Laminated glass is one of the most secure types of double glazing, and it holds together when shattered. It’s made by fusing together two or more layers of glass with polymer interlayers to form a permanent bond. This means that, in the event of a break-in, the broken glass will be supported by the polymer interlayers and hold its shape.

Noise reduction glass

If you live on a busy road or in a noisy area, then you may want to consider noise reduction or acoustic glass. This type of glass is far superior to normal glass in terms of keeping noise out, as it reduces noise by 50%.

Acoustic glass has a decibel rating of between 35 and 42. This is because it is made up of acoustic PVB interlayers, which can be customised by thickness depending on how much noise you want to block out.

What are the benefits of double glazing windows?

Double glazing windows may seem like a simple change to your house, but they bring with them a number of benefits that can save you money in the long run. Installing double glazing can make your home more energy efficient and can also add value to your property should you decide to sell. Here are a few of the other advantages of upgrading your windows. 

Reduced condensation

One of the main advantages of double-glazed windows is that they prevent condensation. This is due to the seal, which is completely airtight and stops moisture from building up on your windows. In turn, this helps prevent damp and mould, which can cause significant health problems as well as costly damage to your property.

Less noise

Another major benefit is that double glazing can significantly reduce sound transmission from outside your home. The additional glass panes reduce noise by an average of 35 decibels.

Lower energy bills

Installing double-glazed units can significantly improve your home’s thermal insulation, as the extra pane of glass reduces escaping heat and incoming cold. You’ll turn on the heating less frequently, which means you’ll spend a lot less on your energy bills.

Increased security

Double-glazed windows will add extra reassurance in terms of security. The units are extremely difficult to break and also have a much stronger seal than other windows, which will deter intruders.

How much can you save with double glazing windows?

Double glazing prevents heat loss, which means you won’t have to use your heating system as much. This will help you save money in the long run, as your energy bills will be lower.

You’ll also save money on repairs. Double-glazed windows are low maintenance, and some frame materials don’t require painting or staining.

Furthermore, double glazing can add up to 10% to the value of your home due to the added security, reduced noise pollution and energy efficiency it provides. For some, this outweighs the cost of double glazing.

The amount you can save will depend on several factors, including the size and type of window, as well as the climate you live in. Typically, you should start seeing savings from your double glazing within the first year of installation.

This table sets out the yearly savings you can expect for homes of various sizes with different energy ratings:

Energy Rating	Detached	Semi-detached	Terrace	Bungalow	Flat
A	£120–160	£80–110	£65–90	£55–75	£40–60
B	£110–145	£70–100	£60–80	£50–70	£40–55
C	£100–135	£75–95	£60–75	£50–65	£40–50

What does installing double glazing windows involve?

Installing double glazing is a relatively simple process. First, the old window will be removed, and the opening will be measured. The new window will then be installed and sealed. The whole process usually takes around two hours.

You may be tempted to save money by installing double-glazed windows yourself, but we recommend employing a qualified tradesperson. Incorrectly installed windows can lead to a number of problems, including draughts, leaks and condensation. Hiring a professional will ensure your windows are installed correctly and you get the full benefits of your double glazing.

What to look for when hiring a professional glazier

When hiring a professional glazier, it’s important to do some research. The following are some of the things you should look for.

Qualifications

Make sure the glazier you employ is qualified and experienced in installing double glazing. Glaziers normally take up an apprenticeship and receive a Level 3 NVQ in glazing.

Experience

We recommend you avoid hiring anyone with less than five years of experience. You should also ask for proof of previous work in the form of pictures, as this will offer reassurance that they know exactly what they are doing.

Insurance

Ask to see proof that your glazier has tradesperson insurance. This will protect you in the event that something goes wrong during the installation process. Tradesperson insurance typically covers any accidental damage to the property, for instance, if the glazier’s tools fall on the floor and cause dents or worse.

Reviews

Read reviews from past customers on the glazier’s website, Google, or Trustpilot to make sure the person you’re considering is reputable and reliable.

Quotes

One of the most important things to do before agreeing to hire someone is to double-check their quote. A typical double-glazing quote should include the material costs and labour rates per hour or day. It should also state when the job will start and how long it will take, as well as whether clean-up is included.

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