It's not a simple answer to say how much does double glazing cost because the cost of new windows is dependent on so many factors such as style and materials.

Many websites do offer lists of prices of their double glazed windows, but these are usually the cost for a basic off-the-shelf window and often without the cost of installation.

Bear in mind, when you're comparing the average price of double glazing online that the prices quoted might not include the bespoke options you need, plus they might be inferior quality double glazing that's a false economy to buy.

We can't stress enough the pitfalls of buying cheap double glazing and hope that after reading this page you can make a better judgement of what you should and shouldn't buy.

To directly answer the question, how much does double glazing cost? - the cost of double glazing is anything between £100 to £3,200 per window, depending on options.

Our guide below covers all the different factors that can affect the cost of double glazing, so you can consider what would be the best option for you.

• Is it worth getting double glazing?
• How much does it cost to double glaze a window?
• How does the style of windows affect the average cost of double glazing?
• How does the material used affect the average cost of double glazing?
• Other options that affect how much double glazing costs
• How much is double glazing for a 3-bed house?
• Double glazing or triple glazing?
• What is the cost of secondary double glazing?
• When should I replace my double glazing?
• How long does double glazing last?
• Does double glazing increase the property value?
• Cheap double glazing windows or quality double glazing?
• What should your quote for double glazing include?
• What double glazing accreditations and standards should I look for?

Is it worth getting double glazing?

Double glazed windows are the most popular choice of windows for homeowners in the UK and the benefits are well proven:

• The weather has a lot to answer for here in the UK and for this reason, being more energy efficient is necessary to keep us dry and warm. A+ double glazing can save up to an average of £110 a year on energy bills.
• Double glazing can make our homes healthier environments as it reduces the build-up of condensation on windows and the growth of black mould.
• If you live in a noisy area, double glazing can significantly reduce the background noise and help you get a better night of sleep. With the rise of noise pollution and its effect on mental health, this alone makes double glazing worth it.
• What really makes double glazing worth it is the increase in property value you can expect and the long-term payback of reduced maintenance costs.
• And, let's face it, good quality double glazed windows make a home look great and makes you feel proud of your home.

How much does it cost to double glaze a window?

As we said above, it's not a straightforward answer to say how much double glazing costs when there are so many variables to consider.

The only way to know how much it costs to double glaze a window would be to have a survey from a double glazing installer who can take into consideration any complications with fitting your windows and advise on the best style of window for your property.

As a rough guide to answer the question of how much does double glazing cost, we've put together a range of prices as a guide below. But, you must remember that these are averages and the cost to double glaze your house could be considerably different. Don't let anyone online tell you otherwise.

How does the style of windows affect the average cost of double glazing?

Other options that affect how much double glazing costs

Apart from the style and material of a double glazed window, there are other factors that will impact on the cost of new double glazed windows.

Size - it might seem obvious but a large living room picture window is going to cost significantly more than a small toilet window.

This is the main reason why it's so difficult to answer the question of how much does double glazing cost.

Energy rating/quality of glass - glass might look all the same but there is a huge difference between the quality of energy efficiency performance.

When buying new double glazing look at the thermal efficiency, the solar gain and the air leakage values. A window rated A++ is the highest rated across all of the above and should be what you choose to make the investment in double glazing worth it.

Furniture and finish - door handles, locks, number of opening windows, colour and any grain effects all need to be factored into the double glazing cost.

Cheap windows might not include extras and you will need to pay more for upgrades to get the handle or locks that you want. Don't underestimate how much the finishing touches can add to a basic price.

How much is double glazing for a 3-bed house?

When budgeting the double glazing cost for a 3-bed house you will need a price for how many windows there are.

An average 3-bed semi-detached house has 3-4 windows at the front and back = 8 windows.

An average small detached house has 4 windows front and back and 2 on the side = 10 windows.

Double glazing or triple glazing?

Just when you got used to buying double glazed windows, along came triple glazed to throw another option into the equation.

The benefits of triple glazed are:

• Thermal efficiency - an extra pane of glass with more argon gas sandwiched between boosts the A+ rating to A++ and the highest rating a window can have. The result is a reduction in energy bills and a warmer house.
• Soundproofing - acoustic glass can reduce sound by 40 dB and make a road seem four times further away.
• Security - one more pane of glass to get through makes a window with serious resistance.

The Energy Saving Trust endorses triple glazing but is it worth it? As we answered above, is double glazing worth it, how much better can upgrading to triple glazing be?

The cost of triple glazing is 10-20% more than double glazing so can you save enough on your energy bills to justify the extra cost?

The predominant reason to consider triple glazing over double glazing would be if you live in a noisy area. If you are situated next to a loud road this can significantly affect the quality of your sleep.

Otherwise, unless you want to enhance your energy efficiency, double glazing is still the most efficient choice of window.

What is the cost of secondary double glazing?

As an alternative to double glazing, secondary glazing might be a more economical option to consider.

Instead of replacing the full window, secondary glazing fits internally over your window recess to give a second layer of insulation over the window.

Why would you choose secondary glazing over double glazing?

• If you live in a period property or have a clause in your lease that stops you from replacing your single-glazed (usually sash) windows.
• You want to retain the style of your original windows.
• You want to eliminate draughts without the expense of new windows.
• You want to reduce the noise if you live next to a busy road.
• Secondary glazing is great for acoustics and can reduce external noise pollution by up to 80%.

The cost of secondary glazing can be up to 50% less than installing double glazing new windows.

When should I replace my double glazing?

Replacing a full house of 8-10 double glazed windows is an investment that will cost several thousand pounds and is a big decision for most people.

We would never recommend for you to replace windows that are in perfectly good condition without any issues. However, it does get to a point when your windows are letting the property down and you would be far better to take the investment rather than making do.

Draughts - the main reason to change windows is that your old ones are letting in considerable draughts and cold which can seriously push up your energy bills.

Double glazing seals can fail so if you can feel cold blowing around the edge of the window it might be time to change them.

Or, your original windows may have been badly fitted with lots of expanding foam around the edges to make up for a poor fit. If this is the case, we would recommend replacing.

Warped frames - older cheap uPVC can warp and discolour leaving windows that look tired and shabby. Warped windows can also cause issues with gaps around the edges letting in cold air.

If your white windows are now the colour of sour cream then it could be time to upgrade.

Condensation - if you have condensation inside the double glazing it indicates the seals on the windows have failed. If you have this problem the only real way to solve it is to replace the windows.

Check with your installer or manufacturer as they might be covered under warranty.

Desiccant - this is where you have bits inside the glass caused by the seals failing.

As with condensation, the only way to solve this permanently is to replace the units with failed seals. Again, check your warranty and guarantee.

How long does double glazing last?

Double glazing lasts for around 20 years but does vary depending on the quality of the window units and the quality of the installation.

Reputable double glazing manufacturers and installers will offer guarantees (at Everest, we offer a standard 10-year guarantee on all windows and lifetime guarantees against internal condensation and discolouration*).

Of course, windows can last far longer than their predicted lifetime and many houses have windows that are over thirty years old - if they've been well-maintained.

The first part of the double glazed window that is likely to fail is the seal and second to that are the hinges.

It also depends on where the windows are positioned in a property. For example, a south-facing window that gets a lot of sun and heat is more prone to discolouring or the seals drying out.

Does double glazing increase the property value?

House buyers in the UK rate double glazing and central heating at the top of their list when looking for a new home. With 80% of buyers citing double glazing as a 'must-have'.

Double glazing can increase the property value by up to 10% if the windows are of good quality and the style and colour are in keeping with the property. Therefore, an investment in new windows can pay back if you are thinking of selling.

Beware though, the windows must suit the property and if you get this wrong you can decrease instead of increasing the value. For example, period properties suit timber frames and traditional sash windows. If you remove old sash windows to replace with uPVC double glazing you can devalue the house.

Cheap double glazing windows or quality double glazing?

Don't ever be fooled into thinking that cheap double glazing is a better option than paying more to install quality windows.

As we highlighted above, fitting uPVC in a period property instead of timber can decrease the property value and turn off buyers.

Poor quality double glazing can have a host of issues and you may also find that a cheap supplier has a cheap or non-existent guarantee. More importantly, only reputable well-established companies can offer a lifetime guarantee with the confidence they will be there in twenty years to replace a window if there is a problem.

Cheap window companies are more likely to not be around to honour warranties when you need them.

For any investment, you make in your home, quality should always take precedence over price. Trying to do anything on the cheap always turns out to be expensive in the long-term.

What should your quote for double glazing include?

If you're comparing the average cost of double glazing from different companies and want to know how much does double glazing cost, make sure you are comparing like-for-like. As we highlighted above, there are many variables to consider that can dramatically alter a price. Even factors like installing in an upper floor that would require scaffolding have to be taken into account.

If you do want to compare quotes then make sure your double glazing cost quote has the following:

• A full technical survey with drawings
• Full product details of size, style, colour etc.
• The number of windows
• The window energy rating (WER) for the glass
• Any additional features, such as handles and locks
• Does it include external window sills?
• When does the work start and finish?
• Disposal of your old windows
• Warranties for installation
• Guarantees for products
• Company details and accreditations (see below)

What double glazing accreditations and standards should I look for?

Building regulations do apply to double glazing window replacement so you must use a reputable company that is registered under the competent person scheme. They give you a certificate of completion that states your windows pass regulation otherwise you have to obtain build regulations permission yourself.

The accreditations to look out for include:

• Competent person scheme CERTASS
• Fenestration Self Assessment Scheme FENSA
• British Standard Institute BSI
• The Glass and Glazing Federation GGF

You can read about Everest accreditations here and an explanation of CERTASS here.

How much does double glazing cost? (recap)

The average cost of double glazing for a white uPVC casement window ranges between £100 to 1,230* depending on size and how many are being replaced in the property.

*Industry average prices

Are you thinking about new double glazing windows?

We do a full survey of your home and help you to choose from 1,000s of different configurations so that you get the windows that are right for you.

Our windows are guaranteed so you have peace of mind you made the right choice.

See what double glazing windows you could have…