✔ Double glazing costs £640 per window, on average
✔ You could save up to £145 per year with double glazing
✔ Fill in the form above to get free quotes for new windows
Double glazing is a win-win-win: it can save you money, make your home harder to burgle, and keep you shielded from the noise and cold of the outside world.
But you’re not about to make a major change to your home without making sure you can afford it. That’s why you’re here: to work out if double glazing is worth it.
What’s on this page?
Average cost of double glazing per window
On average, double glazing costs £640 per window – but it can be at least a couple of hundred pounds cheaper, with top quality double-glazed windows, available for as little as £300. On top of this, installation can cost around an extra £250, but it’s worth it for that professional touch.
Bear in mind that if your installer needs to put up scaffolding to get to your window, that’ll also cost extra – and the higher the window, the higher the price.
If you’re getting a bay window replaced, installers will also need more time (and, therefore, more money) to fit it. It’ll take about half a day for two people, whereas simpler models like casement windows can be done and dusted in a couple of hours.
The cost of double glazing in different types of window
Every window is special, standard sizes don’t really exist, and every supplier will charge you different amounts – but you need to be able to compare prices.
Before you can work out how much double glazing will cost you, you need to choose a frame material.
So here’s how much a single 100cm x 100cm double glazed window will cost you on average with different types of frame, to give you an idea of what to expect.
The cost of double glazing based on house size
To give you an idea of how much you can expect to spend on your new double glazed windows, we’ve outlined some prices that will align with the size of your house.
The graph below shows how much a set of windows will cost you, depending on the amount you get, as well as the material you pick. But remember, this is just an estimate – the price of your windows will fluctuate depending on the size, type, and style you choose.
If you’d like to learn more about the cost differences between window types, head over to our Best Double Glazed Windows page.
How do colours and types of glass affect the price of windows?
Not only does the frame affect the price of your window, but the glass does, too. Double glazing has come on leaps and bounds in the past decade, offering a range of different types of glass which all serve a different purpose.
If you’d like a basic double glazed window, you could go for annealed (otherwise known as float) glass. It’s the cheapest option, but is still particularly difficult to break. On the other hand, if you want to go for an even stronger glass, such as toughened or tempered glass – which is about three to four times tougher than float glass – this will cost you.
You’ll also be looking at additional costs if you want to add a splash of colour to your windows. You should expect to pay an extra amount of between 10% and 20% of the cost to add a colour finish.
How much do different double glazing designs cost?
Your next move is to choose a window design. This decision may be made for you – after all, a bay window is difficult and expensive, though not impossible, to convert into a flat window – but otherwise, it’s completely up to you.
There is a wide range of prices, but in general, casement windows – with their simple hinges and traditional appearance – are the cheapest option. There’s a reason why they’re the most common window type in Europe.
However, sash windows are more popular in the UK these days. They usually aren’t much more expensive, and are just as intuitive as their casement counterparts: just push up or down to open and close.
You could also opt for the slightly pricier tilt and turn, which can be opened horizontally or vertically, or a dual turn, which is a sash window where both parts rotate vertically instead of sliding up and down.
And of course, if you want to let in more light, create the illusion of a bigger space, or simply make your window the main attraction of whatever room it’s in, you can go for a bay window – but it’ll cost you. The average bay design is twice as expensive as almost any other type.
Double glazing cost calculator
Use our double glazing cost calculator to check how much you’re likely to pay for your new windows.
If you want to see how much you could save, complete this form to receive quotes for brand new windows.
What affects the average price of new windows?
As mentioned above, a window’s style and frame material will affect its value, but there are other factors to consider.
The price of your new windows can vary greatly depending on which double glazing company you choose. Plus, if any of your new windows have to be installed on the second floor of a home, you might need scaffolding, which will cost extra.
It sounds obvious, but you should also think about how many windows you want to buy. If you get two instead of one, it’s almost twice as expensive – around £1,100 compared to £640.
But if you’re struggling to meet the costs, that’s okay. There are double glazing government grants available in the UK, and you may well qualify.
Factors which will affect the price of double glazing
Cost of replacement vs new double glazing
When your old window isn’t working properly anymore, it’s tempting to go for the cheaper option and just replace the glass. This would be a mistake.
While it’s cheaper at first to just get your double-glazed glass replaced and leave your old frame in place, you could quickly lose everything you gained from this initial saving.
Firstly, the issues you’re trying to address will remain.
You want your window to be better at insulating you from the loud noises and cold winds of the outdoors, and therefore reduce your energy bills.
For this, you’ll need a new frame as well. Getting replacement panes means you’ll have better glass, but an old frame can also have a sizable impact on your energy efficiency, and may not fuse with your new panes properly.
In this case, the replacement glass will be a costly and useless purchase. Most major window companies won’t just replace your glass, and there’s a reason: it doesn’t solve the problem.
Get a new window, and save hundreds of pounds in the long run.
The average cost of double glazing your home
The cost of double-glazed doors
Prices start as low as £300 for a 90 x 210cm front door with double-glazed glass, though this will rise to around £550 when you include the installation cost.
The average overall cost for a double-glazed front door is £700, though your exact price will depend on the materials used, your supplier, and how large your product needs to be.
Sliding French doors with double glazing carry a heftier price tag, and the bigger they are, the harder they are to afford.
You can expect to pay an average of £1,200 for this type of design, though prices can go as high as £2,000 – so make sure to decide beforehand how much you want to spend.
Which frame option is right for your double glazed window?
In these glorious modern times, a plethora of options are available to consumers of double glazed windows, all with their own advantages and disadvantages.
You could choose the new plastic kid on the block, uPVC, which has risen to prominence either side of the millennium. It’s cheap, low-maintenance, and durable, which might be why it’s the most popular frame material across Europe.
Around six million uPVC windows are sold each year in the UK – twice the number of wooden frames. This may be down to wood’s more expensive price tag and its neediness (it requires more maintenance, to prevent rotting, mould, mildew, and peeling).
However, wooden frames look great, and are much better for the environment – it takes eight times more energy to create uPVC frames when compared to wooden ones.
Wooden frames also insulate heat much better than steel or aluminium, keeping you nice and toasty on those cold winter nights – though again, they lose out to uPVC in this category.
Though steel and aluminium are worse at insulating you against the slings and arrows of our changing seasons, they are slim and long-lasting, and can be recycled. They also look sleek and modern, which matters when you have to look at them every day.
Double glazing vs triple glazing
Triple glazing is undoubtedly better than double glazing – but triple glazing costs more, and seems unnecessary for homeowners in Britain.
The best measurement to compare the two is their U-value, which puts a number on how good a window is at insulating your home. The score is measured by how many watts per square metre per Kelvin (W/m²k) are released from your home – the lower the number, the better your windows are.
Double glazing typically scores 1.1, while triple glazing gets an average of 0.6. Triple glazing is therefore around twice as good at keeping the heat in and the noise out.
These attributes have made triple glazing commonplace in colder countries like Norway and Sweden – but of course, higher quality means paying a higher price. After all: with great power, comes great financial cost.
Maybe this is why triple glazing hasn’t taken off in the UK. In a 2015 study, 92% of window installers said triple glazing sales had made up less than 5% of their turnover over the past year. Considering the added cost, triple glazing isn’t a must-have in the British climate. We’re cold, but not that cold.
You should also bear in mind that triple glazing is great at keeping the heat in – and out. If you have south-facing windows, double glazing will let much more precious warmth into your home.
Getting three panes of glass instead of two should mean spending around one-third more than you would for double glazing – but many suppliers charge even more. If you can get triple glazing for £960 or less, you’ve got a good deal, on average. Otherwise, it’ll take even longer to recoup the difference through your energy bills than it would with double glazing.
How do I know if my double glazing needs replacing?
Everything falls apart eventually. The universe tends towards atrophy, and so do double-glazed windows. They should last around 20 years – but when it’s time, it’s time.
7 ways you can tell your double glazing needs to be replaced
- Water is leaking through the frame
- Condensation appears between the two panes
- The glass is cracked, chipped, or broken
- You can feel a draught coming in through the window
- Much more noise from the outside world is getting in
- The frame is soft – this can indicate rot and/or water infiltration
- It’s harder to open, close, or lock – this makes your home more vulnerable to burglars, and can be a sign that your window is rotting, rusting, or wasn’t installed properly in the first place
Is double glazing worth it?
Double glazing is absolutely worth the investment, as long as you can afford it. Your wonderful new windows will leave you with a home that feels warmer, quieter, and more well-protected from burglars.
It even pays for itself in the long term, and can add as much as 10% to your home’s value.
You don’t need to wait until your old windows lose their effectiveness completely, either. A huge variety of new designs are waiting for you right now, ready to improve your life.
And because we want you to make the right choice for you, here are the key steps to ensure you spend the least money on the most high-quality product possible.
Based on a survey we conducted in May 2018 with 775 homeowners who had installed new double glazed windows in the past two years.
7 tips to help you get the best deal on double glazing
- Shop around and get multiple quotes
- If you get a company to measure your windows and give you a quote at home, hear them out – but don’t sign a contract on the spot
- Hire a professional to install your new double-glazed windows
- Get a locally based company for the installation, as its workers won’t have to spend as much time travelling to and from the job, and therefore won’t have to charge you extra
- Check you don’t live in a conservation area or listed building
- Decide ahead of time how much you and your loved ones want to spend on the new windows
- Check the U-value of a window before buying it – it should ideally be around 0.6 or lower
Cheap double glazing vs quality
Getting a good deal is usually one of the top priorities when it comes to buying double glazing. And with so many double-glazing companies offering windows or doors at cheap rates, it can be tempting to go for the cheapest option.
This, however, would be a mistake. A lot of the time, the less costly option will only leave you with cheap, inefficient double glazing. Your product will wear down quickly over time, and leave you with a poorly insulated home.
Secondary glazing can cost anywhere between 25% and 50% less than double glazing.
Unlike double glazing, secondary glazing can also be installed by the buyer, meaning you may be able to do it yourself – with more than a little help from the instructions and while using the correct safety gear, naturally.
Secondary glazing is the process of adding another, thinner glazed pane of glass to the inside of a single-glazed window.
There are two kinds of secondary glazing: one aimed at stopping draughts, and a more expensive version which focuses on reducing the level of noise that comes from outside.
Secondary glazing is cheaper, and means you don’t have to replace the entire window. This makes it perfect for renters – but it’s still less effective than double glazing.
Double glazing is generally around twice as good as secondary glazing when it comes to keeping heat in and reducing condensation.
Reasons to get secondary glazing
If your home is a listed building, if you can’t get planning permission to get double glazing for a different reason, or if you don’t want to change the look of your beautiful window, secondary glazing may be your best or only option.
You should also consider secondary glazing if you’re on a budget, though double glazing will save you more in the long term.
If you’re desperate to protect yourself from loud noises, there’s good news for you: soundproof secondary glazing is better than double glazing in this department, as the panes are further apart.
Who can fit double glazing?
It’s actually possible to fit double glazing yourself – but it’s not recommended. Although you’ll be able to save money on the installation, it could lead to inefficient windows, more expense in the long run, and possibly an injury.
What accreditations should I look for?
The following authorities play an important role when it comes to ensuring high standards in the double glazing industry:
- Fenestration Self-Assessment Scheme (FENSA): Members who are registered with FENSA are compliant with up to date thermal performance standards, which means that the double glazing they install meets the necessary energy-efficiency standards
- Double Glazing & Conservatory Ombudsman Scheme (DGCOS): Monitors UK double glazing installers to make sure they meet appropriate quality and service levels. This means that those using a DGCOS-registered company are able to benefit from increased protection
- Certass: This government-backed agency operates on a not-for-profit basis, and aims to increase consumer confidence through the evaluation of registered contractors
- TrustMark: TrustMark endorses companies in a variety of trades and industries as long as they meet government approved guidelines and standards
How much can double glazing save you?
We’ve outlined how much money you could save each year if you install double glazing on an entirely single-glazed house:
Data from .Gov
What should your double glazing quote include?
Your double glazing quote should provide you with an estimated price of replacing your windows – tailored to your specific requirements.
Since there are so many varying factors affecting the price of windows, we wouldn’t recommend relying on just one quote. This will give you a better idea of what a reasonable price actually looks like.
Local vs national installers: who should you choose?
Local and national installers both have their pros and cons. On the one hand, local installers are likely to provide a cheaper deal, whereas national companies are more likely to be trusted by users because they’re more well known. You can learn more about local and national double glazing companies, which one will be better for you, and how we rate them by visiting our Best Double Glazing page.
What type of double glazing do I need?
There are lots of different options when it comes to the type of double glazing you want for your home – however, the one you go for will depend entirely on your circumstances. We’ve listed a few of the main options below:
- Annealed or float glass – This is basic double glazing glass. It’s the cheapest option, quite strong, and difficult to break, especially when used in double glazed fittings
- Toughened or tempered glass – This is about three to four times tougher than float glass. However, because of its safety features and specialised manufacturing process, it’s one of the more expensive options
- Laminated glass – This acts as a layer of security for your double glazing. The PVB (polyvinyl butyal) laminate is very secure – if the glass ever breaks, it remains stuck to the laminate
- Noise-reduction glass – This glass has acoustic inner layers of PVB, which absorb sound so that very little of it makes its way inside. To make it even more effective, you can use layers of different thickness
Double glazing costs a sizeable amount, but it can improve your life in a variety of important ways.
If you’re ready to buy a new window which will help you to banish the cold, repel external sounds, exile condensation, and keep burglars out, then double glazing is the one for you.
Fill in your details for free quotes and get moving towards your double-glazed future.