Double Glazed Windows Cost Guide: How Much To Install?

If you’re looking to add double glazed windows to your home but you’re concerned about the costs, our handy guide will cover all of the different fees involved as well as the pros and cons of double glazing.

Are Double-Glazed Windows Worth It?

Double glazed windows, also referred to as an IGU (Insulated Glass Unit), are ideal for improving the energy efficiency and safety or your home. Their initial installation can be confusing due to the huge variety of windows available and their varying costs.

But don’t worry: we have compiled this useful guide of UK double glazed window costs to explain the various prices, types and everything else about double glazing.

What are Double Glazed Windows?

Double glazed windows are external windows that feature two panels of glass separated by a pocket of air or gas. The space between the panels acts as an insulation barrier to prevent airflow in either direction.

They’re the most commonly found windows in the UK and fitted as standard on new build houses.

Average Cost Per Window

The average cost of double glazing is between £400 and £600 per window with labour included. Prices will also vary on whether your windows are made-to-order or a standard window shape. Large and awkwardly shaped windows will likely be quoted at a higher price.

The type of material will also have a large effect on the cost of your windows. Additionally, the area in which you live will affect the cost of your window installation.

How Does Property Size Affect the Cost?

The size of your property will have a large effect on the cost of your double glazing. Double glazing for a household is usually charged by the window. Subsequently, the more windows you have on your property, the greater the cost will be.

For example, a small ground floor flat will likely have around five windows. This would make the average cost around £2500.00. Whereas, an average three bedroom household with 12 windows will likely cost around £6000.00.

How Much Do Different Styles Cost?

When it comes to double glazing, there are several different types of window available. Energy ratings go from A++ to E. There’s also a choice of window frames including uPVC, wood and aluminium. You may also come across different types of windows including casement, sash, tilt & turn and a dual turn window.

The following are the most common types of windows you will be able to choose from:

Casement Window

A casement window is attached to its frame by at least one hinge. It opens outwards from the top or side from the direction in which it’s installed. Casement windows are the cheapest option available starting at £270.00 for a small window.

Window Size	Price per Casement uPVC Window
50cm x 50cm	from £270 to £350
100cm x 100cm	from £370 to £420
120cm x 120cm	from £370 to £460

Sash Window

A sash window is made of at least two smaller panels, but usually four, and attached to a divider. Stash windows begin at £540.00 for a small window. The greater the number of panels, the more the price will increase.

Window Size	Price per Sash uPVC Window
80cm x 80cm	from £540 to £720
100cm x 100cm	from £640 to £820
120cm x 120cm	from £750 to £970

Tilt & Turn Window

Tilt and turn windows open into the property. They can be opened fully or cracked open. Prices start from £410.00.

Window Size	Price per Tit & Turn uPVC Window
80cm x 80cm	from £410 to £580
100cm x 100cm	from £480 to £620
120cm x 120cm	from £520 to £680

Dual Turn Window

A dual window has the appearance of a sash window with the functionality of a tilt and turn window. Prices begin at £430.00 for a small window.

Window Size	Price per Tit & Turn uPVC Window
80cm x 80cm	from £430 to £670
100cm x 100cm	from £520 to £670
120cm x 120cm	from £540 to £720

How Much Do Frame Materials Cost?

In addition to the types of windows, there’s also the choice of frames which largely vary in price:

uPVC Window Frame – A uPVC frame is the cheapest type of window available. uPVC is also known as unplasticized polyvinyl chloride. It has a plastic appearance and is available as standard in white as well as many other colours. uPVC begins at around £500.00.

Aluminium Window Frame – An aluminium window frame has a metallic look. They’re generally available in several different colours. Prices begin at around £540.00.

Wooden Window Frame – Wooden window frames are the most expensive and require the most upkeep. They’re usually made from timber and other hardwood. Prices begin at around £840.00.

Double Glazed Sliding Sash Windows Cost

A sliding sash window has a design similar to the standard sash window but is considered more complex. Rather than pushing out, they have an internal sliding mechanism allowing the window to move up and down. This has a much more traditional look that may be preferable on an older style house.

The cost of a double glazed sliding sash window is greater than that of a normal sash window. Fees begin at around £700.00 due to the advance mechanism.

Double Glazing Bay Windows Cost

Bay windows are the most expensive double glazed windows available. This is due to the large area of glass required and the large frame used.

The starting price for a double glazed glass window is around £1000.00 with a maximum price of around £2000.00.

Double Glazing French Doors Cost

As well as windows, you can also have double glazed doors. The most common types of doors with double glazing are French doors.

French doors are an all-encompassing term for patio doors which swing outwards from a hinge.

The cost of double glazed French doors varies depending on the size and number of panels. The cost will usually begin around £1000.00 but do vary greatly.

Double Glazed Window Repair Cost

If you have an issue with a single window and need it replaced, it will be cheaper for the window to be repaired rather than replaced. Although not all windows can be repaired, this depends on the fault with the window.

To have a single double glazed window repaired, the prices will fluctuate depending on the fault and require an individual quote for accurate fees. Each individual company will have a different price so contact a few suppliers for a price.

If your window needs to be repaired within the guarantee period, the manufacturer will be responsible for any repair fees.

Replacement Double Glazing Cost

If your window needs to be replaced, the price of a single window is the same cost as the average cost of a new window. This is around £400.00 to £600.00 depending on the size and type.

The price may be less if only the glass in the window needs to be replaced but an inspection is required to identify this.

How Much Can Double Glazing Save You?

Thanks to the energy efficiency of your double glazed windows, they can help to save you money by reducing the cost of heating your home. Double glazing will help retain heat and stop cold air getting into your home.

The Energy Saving Trust estimates that installing A++ rated windows can save a detached house around £115.00 to £120.00 in England, Scotland and Wales. In Northern Ireland, a detached house with A++ rated double glazing can save you around £145.00 a year.

Saving Your Money In The Long Run

The small savings with double glazed windows will quickly add up over the expected lifespan of a window. For example, if you live in England and install A++ rated windows that last 20 years, you could save up to £2400.00 on your energy bills. For the same length of time in Ireland, you could save a huge £2900.00 on your energy bills. These saving will also increase with the inflation in energy bills.

These costs begin to outweigh the price of the double glazing and when coupled with the environmental, safety and overall look of the windows.

Double Vs Triple Glazing Cost

There may be some places where double glazed windows don’t meet the demands of your environment. This is common in Nordic countries where winters are long and harsh.

With triple glazing, an additional panel is added to create two internal barriers rather than one. Triple glazed windows usually use gas rather than air, with Krypton commonly utilised for advanced insulation.

The price of triple glazing is usually at least ⅓ more than the cost of double glazing, however, prices will vary based on the type of window, supplier etc.

In terms of the UK, triple glazed windows aren’t usually required and double glazing should be sufficient.

Does It Increase Property Value?

It is thought that adding double glazed windows can increase the cost of your home thanks to energy efficiency, increased safety, the aesthetics and the easier upkeep.

It’s difficult to work out the exact increase on a property as this depends on the window’s rating and the housing market. However, it’s thought that up to 10% could be added to the value of the property in some circumstances.

Not only is double glazing thought to increase the value of the property, but it’s also thought that a home with single glazed windows is less likely to sell by comparison. Having to change windows after purchase can be offputting to potential buyers.

How long does double glazing last?

Although double glazed windows have a long lifespan, they won’t last forever. The average lifespan of double glazed windows is thought to be around 20 years, however, this will vary depending on your supplier and the quality of their materials and the installation.

Some retailers and manufacturers will offer a double glazing guarantee so make sure to check whether you’re covered before signing any contracts.

Double Glazed Window Features

As we mentioned, a double glazed window is made up of a frame with two panels and an air or gas layer in between. The air or gas layer acts as insulation to create a barrier between the hot air inside and the cold air outside.

The makeup of the window has many benefits when compared to that of single glazed windows. This is why they’re recommended for every home in the UK.

Double Glazing Pros

• • Improve your home’s safety – When compared to single glazed windows, double glazed are significantly harder to break. There are also additional safety features available such as locking mechanisms and fire exits.
  • Improve your home’s efficiency – Cut down on your energy bills by retaining heat. This is done by stopping hot air escaping and cold air getting in thanks to the insulation layer and advanced frames.
  • Increase the property’s value – Increase the value by up to 10% as well as the likelihood that the property will sell.
  • Reduce sound pollution – Cut down on the outdoor sound that gets into your home. This is thought to be around 31dB, ideal for cities and noisier areas.
  • Improve home’s look – New double glazed windows can give your home a fresh and neat look that suits most houses. The choice of window and frame styles make double glazing flexible to many homes.
  • Long lifespan – Double glazed windows are thought to last around 20 years and the majority of the suppliers offer a five to ten-year guarantee.

Double Glazing Cons

• • The initial window cost can be high – Initial outlay is high, however, payment options are available with some companies and money will often be recouped with overall energy savings.
  • Repairs can be difficult – In some cases, replacements are easier than repairs. This will depend on the type of damage and age of the window.
  • Doesn’t suit the style of every home – As the number of styles is limited, double glazed windows and their frames may not match the aesthetic of your home.

How Does Double Glazing Reduce Heat Loss?

Adding windows with double glazing can act as a barrier to stop heat from escaping from your home. Along with your roof, windows are one of the principal areas where heat escapes from your home.

Double glazing stops heat escaping from your home by creating an air or gas insulation layer between the two panes of glass. This is between the cold air outside and warm air inside, stopping the hot air from escaping and cold air getting in.

Double glazed windows are available with different energy ratings, depending on their efficiency. Ratings from A++ to E are given by the British Fenestration Rating Council (BFRC). Ratings take into account the gap between the window panes, the frames and whether gas or air is used.

What Security Features are Available for Double-Glazed Windows?

Double glazed windows come with a number of additional security features to improve their safety. Different features are available to help prevent intrusion and provide safety to residents.

The following are the key safety aspects of double-glazing:

Lockable Handle – Add an extra level of security by locking the handles in place.

Internal Beading – Windows with internal beading rather than external beading cannot have the window frame removed from the outside reducing the chance of unsolicited entry.

Multiple Locks – Adding locks to more than one area of the window will help to prevent intrusion.

Shoot bolts – Shoot bolts are available on the top and bottom of the window to help prevent the window from being popped open.

Shatterproof Glass – Shatterproof glass makes a window harder to smash, preventing intrusions. Also, if a window does smash, shards of glass will be limited, helping to prevent injury.

Easy Escape Hinges – Escape hinges allow the windows to be opened to a 90-degree angle for an easy escape in an emergency.

When Should I Replace My Double Glazing?

The estimated lifespan of the double glazed window varies based on the supplier and the products they use. However, it’s estimated your double glazing will last at least 20 years if materials are of high quality. There are several warning signs to look out for which signal your double glazing is due to be replaced:

Condensation is visible between the window’s panels – This signifies there’s a hole that has let water into the insulation layer. Don’t worry if condensation is visible on the inside or outside panel as this is common due to the UK’s high humidity.

Any leaks – Investigate any moisture found around the window sill or frame. This may be let in through a hole in the window frame.

Windows let in cool air or a draft – Check for drafts on windy days to test quality.

There’s visual damage on the window or its frame – Minor issues will likely be possible to repair but bigger issues may not.

Opening and closing the window is effected – Windows are obstructed or too stiff/loose during opening and closing.

Some window issues may be possible to be repaired rather than replaced. This is mainly applicable for window seals or smaller frame damage. Although, if your window is old, it may be a sign further issues are to be expected in the near future. Seek advice to find out whether a window is worth repairing or a replacement is more cost-effective.

Building regulations for new windows

In the event you live in a conservation area or in a listed building, you likely won’t be allowed to install double glazing windows. In such cases, secondary glazing is really a reasonable alternative – always contact your local building authority prior to making any changes.

All new windows must meet UK building regulations to make sure they meet thermal standards. To make sure your double glazing meets these standards, it’s best to hire a window installer registered with a self-evaluation scheme such as for instance FENSA. They will inform the local authority that the windows comply with regulations and supply you with security to establish this.

What are My Rights When Buying Double Glazing?

In the UK, double glazing comes with a number of laws in place to ensure the consumer is protected following their initial order. This covers cancelling your double-glazing order through to resolving any issues with guarantees following your installation.

Cancelling Your Order

Your right to cancel your double glazing order can vary depending on the circumstances. This will include the type of windows and your specific contract.

You will not have the legal right to cancel an order if your contract was signed on the premises of the company, if a company employee or representative discussed the options and signed the contract in your home or if your windows are custom made to order. You still may be able to cancel in these circumstances, however, it comes down to the individual company and agreement.

You will have a legal right to cancel your order within at least 14 days if the contract is verbally agreed or signed under the Consumer Contracts (Information, Cancellation and Additional Charges) Regulations 2013 or if a contract was agreed online or by phone.

Rights with Double Glazing Problems

The Consumer Rights Act 2015 provides cover for your double glazed windows. The Act states that the installation should be: complete with ‘reasonable care and skill’, the materials should be of ‘satisfactory quality’ and ‘fit for their purpose’ as well as being ‘as described’.

These requirements must be met or a repair/replacement must be given in a ‘reasonable time but without causing significant inconvenience’.

This information covers both the company from which the order was placed and any subcontractors completing the work.

Resolving Double Glazing Issues

Should any issues arise with the company, the below process should be followed to rectify the situation:

Speak to the company and outline the issue. If communication is verbal, follow up with written confirmation of any conversation

Agree on a date you expect the issue to be resolved by.

If the agreed date passes, send a final ultimatum. This should include a new deadline and the action you will take if not resolved. The action should include that you will have a third-party complete the work and claim any fees back along with the next step of taking the claim to court for fees.

Involve a third party such as the GGF, DGCOS, BSI or Fensa. The Glazing Arbitration Scheme may take your case to arbitration.

You can arrange for the issue to be fixed by another party, however, you will have to prove the other steps have been followed to claim back money.

Should the company not repair the issue or pay for the repairs, you should begin court proceedings in a small claims court.

If the work is paid for using a credit card, the credit company may also be liable for the fees if conditions are met. This is covered under the Consumer Credit Act 1974.

What Should My Quote Include?

When requesting a quote for the price of double glazing for your home, you should check the following information is included:

• • Cost for windows
  • Cost for time and labour
  • Cost of VAT & whether it’s included
  • Any additional costs
  • All known & expected fees

Frequently Asked Double Glazing Questions

How much does it cost to replace a sash window?

The cost of replacing a sash window depends on the style, size, material and glazing. Replacing your sash windows with double glazing sash units can cost from £700 to £1,300 per window. Upvc windows are the cheapest option and wooden windows the most expensive. 

Can you put double glazing in sash windows?

It depends on the type of windows but it is not considered a great practice as the glazing bars might not accommodate the sashes. Wooden sash presents many problems related to the depth of the glazing bars, lack of a clear drained gap around all four edges of the sealed glazed unit and securing the wooden sash with linseed-oil putty, which draws the plasticiser out of the edge sealant and causes it to dry out and crack. 

How much does it cost to refurbish sash windows?

The cost to refurbish sash windows depends on their condition. Overhaul and draught proof cost between £200-£400 per window. If sills and major repairs are required, expect to pay around £150 – £300 per window unit. For replacement windows expect to pay from £300. 

Should I replace my old sash windows?

Even though most sash windows are made of timber and have a tendency to rot and warp with the years, replacing your sash windows with double glazing is not a good option as they are very expensive and not cost effective in terms of energy efficiency. The best option would be to install uPVC sash windows, as they require very little maintenance, are thermally efficient and can be customised to avoid sacrificing the aesthetic of your home. 

How much does it cost to double glaze a 3-bed house?

The cost for a 3-bed house to install double glazing depends on the number of windows and UPVC doors needed and the suppliers buying power. So, if we take into consideration the average double glazing window cost (£300 – £350 per unit) and the cost of a Upvc door (£600), expect to pay between £3,500 and £5,500 for a standard 3-bed semi home. 

Why Is uPVC Used For Window Frames?

Upvc is used for window frames because of its excellent performance, durability and low maintenance. Upvc window frames are also thermally efficient, sound insulating and low cost, which makes them a great value for money. 

Is Double Glazing Unbreakable?

Double glazed windows are extremely strong and it takes a great deal of effort to break them, especially if you want to avoid making a lot of noise. Modern windows always come double glazed so there are two layers to get through if you want to break the window.

What is the life span of Double Glazing?

Typically, you can expect double glazing to last about 200 years although depending on the quality of the windows you could see a variation of this. Some may last as little as 10 years, whereas others could be good for up to 25 years. However, installation, material and location of the windows play a role and the gas contained between the two panes of glass will eventually start to leak out.

How long will I wait for the installation of a new uPVC Window?

The installation of replacement windows normally takes place around 4-8 weeks from the time the final measurements were made. The amount of time may vary according to the type of window you are removing as well as the window being installed. Both of these factors influence how long the job will take, but the average time is around 30 minutes.

How Can I Tell If My Double Glazing Should be Replaced?

There are four signs that your double glazing needs replacing. These are:

1. There is water leaking through the frame;
2. You start to see condensation appearing in between the panes;
3. The appearance of cracks/chips in the glass;
4. You are starting to feel draughts coming in through the frames.

How Long Does Double Glazing Installation Take?

It usually takes about 30 minutes to install one window, however, this will depend on the size of the actual window. There are several factors that influence the amount of time you can expect your window installation and some installations can take up to two days.

Why Should I Consider Double Glazing My Windows?

Double glazing is one of the best ways to increase the energy efficiency of your home leading to savings on your heating bills. If you fit double glazing to a previously single-glazed home you can expect an increase of thermal efficiency of up to 80%. With modern factory made double glazed windows you could see an increase in efficiency of 100% when compared to a single glazed window.

Why can Double Glazing Crack?

Double glazing can crack and it is not always obvious why the cracks occur. One of the reasons may be that the glass is under constant pressure within a sealed unit. However, the glass used for double glazing is designed to be strong enough to resist this. Winter is often the time that a crack can appear and this can be due to temperature stresses. The glass is exposed to different temperatures on the inside and outside and this can cause enough stress for cracks to occur.

Can I Have My Windows Installed In Bad Weather?

Window installation can be done in any weather, however, you will need to consider the safety factors. If it is not safe for the installers to carry out the work it may have to be rescheduled. Additionally, window installation leaves an open hole for a period of time and this could lead to weather damage of internal property and furnishings.

Is uPVC Flammable?

uPVC is not flammable and is fire retardant.

How Long Will The Installation Take?

It normally takes about 30 minutes to install a window. The exact time will depend on the size of the windows. However, some installations can take up to two days depending on a range of factors.

Does Double Glazing Block Sound?

Double glazing is not soundproof, but it can reduce the amount of noise entering the home. The reason this works is because of the way sound waves work. Be wary of any companies claiming that their products are soundproof.

Can Double Glazing be broken easily?

It takes a lot of force to break a double glazed window. Breakages are often noisy. All new modern windows that come with double glazing provide two obstacles to break through.

What is the lifespan of double glazing?

Most double glazing will last for about 20 years, however, the range is between 10 and 35 years depending on the installation, where the windows are located and, of course, the quality of the materials used. It is normal that the gas between the panes of glass leaks out over time.

Does it Take Long to Install New uPVC windows?

Replacement windows are usually installed around 4-8 weeks after the final measurements were made. A lot depends on the type of window you are replacing and what you are replacing it with but the average window takes around 30 minutes installation time.

Do I need to replace my double glazing?

There are Four signs that your double glazing needs replacing. These are:

1. You start to have water coming in through the frame;
2. There is condensation appearing in between the 2 panes of glass;
3. The glass is showing chips or cracks;
4. You can feel draughts come in via the frames.

How long does window installation take?

On some occasions, window installation can be a two-day job and this can depend on multiple factors, however, on average windows are installed within around 30 minutes.

Should I Have My Windows Double Glazed?

The way that double glazing can benefit you is with a reduction in your heating bills. Double glazing will make savings on your energy bills, making your house more efficient to heat. If you decided to have double glazing retrofitted to your existing windows you stand to improve the energy efficiency of your home by up to 80%. AGood quality factory-made double glazing is often up to 100% more efficient than a single glazed window.

What Causes Cracks in Double Glazing?

Cracks can appear in double glazing for a number of reasons but equally, they can randomly occur for no apparent reason at all. A sealed unit places constant pressure on the glass, however, this is rarely the cause as double glazing is made to be strong enough to resist this. Winter sees the majority of cracks appearing and this is likely to do with temperature differences inside and outside exerting stress on the glass.

If It is Cold or Raining Can I Still Have My WindowsInstalled?

Although windows can be installed whatever the weather, the safety of the installation team is a key consideration. Also, removing a window can leave a hole in the property meaning that your belongings and furnishings could become exposed to the elements.

AreuPVC Windows A Fire Risk?

No, uPVC is inflammable and fire retardant.

How Long Will My Windows Take To Be Installed?

Depending on size, a window installation would take around 30 minutes. However, there are other factors which can increase the time to up to two days.

Will Double Glazing Block All Sound?

Some double glazing companies may tell you that the windows are soundproof, however, this is not so. It is the nature of sound that makes double glazing good a noise reduction, not the frames themselves.

References

https://www.uniquewindowslondon.co.uk/2017/10/double-glazed-windows-features/
https://www.which.co.uk/reviews/double-glazing/article/how-to-buy-double-glazing/your-rights-when-buying-double-glazing
https://www.doubleglazingprices.org.uk/double-glazing-reduce-heat-loss/
http://www.askjeff.co.uk/double-glazing-is-not-so-amazing/
https://www.getawindow.co.uk/window-glass/double-glazed-units/
https://www.energysavingtrust.org.uk/home-energy-efficiency/energy-efficient-windows
https://www.gandlwindows.co.uk/news/how-much-value-does-double-glazing-add-to-a-home/
https://www.theecoexperts.co.uk/double-glazing-costs
https://householdquotes.co.uk/how-much-does-triple-glazing-cost/
https://www.doubleglazingontheweb.co.uk/news/double-glazing-prices-2018/
https://www.telegraph.co.uk/lifestyle/interiors/jeffhowell/8365991/Home-improvements-Shall-I-have-my-sash-windows-double-glazed.html

Author Bio

This post was written by David Atkinson from Perfectly Engraved, a leading retailer of engraved gifts, awards and trophies.