Double Glazing: Pros, Cons & Costs


Insulating your home is a great way to keep your home warmer for longer and retain the heat, which is more important than ever in these trying times.

Double glazing is one of the most effective ways of preventing heat loss, reducing condensation and external noises, especially important for those living near busy roads.

What is Double Glazing?

Double glazing is composed of two panes of glass, instead of just one that you would find in traditional windows, adding a second layer of insulation to the property.

This means that instead of just one layer of glass between you and the heat or cold outside, you have a second layer of glass that provides even more insulation.

This additional insulation helps to reduce the amount of heat or cold that gets into your home, keeping your rooms warmer for longer and reducing the need for heating or cooling in the first place.

The two panes of glass do not actually touch each other and in between them contains a gas, typically argon that helps to slow down heat transfer and insulate your home.

Advantages of Double Glazed Windows

Double glazing is an effective way of reducing the amount of heat that gets into your home, which in turn reduces the need for heating and cooling.

The two panes of glass in your windows act as an extra layer of insulation, helping to retain the heat in and lowering your heating bills. Double glazed windows are usually made of polyurethane or polyvinyl chloride (PVC).

There are many other benefits of double glazed windows, including the following:

  • Insulates against draughts, a leading cause of heat loss in UK homes.
  • Reduce condensation, which is important in preventing the build-up of damp and mould.
  • Reduce the impact of external noises, especially important for those living near busy roads.
  • Improved security, since having two panes is makes it more difficult to break.

Disadvantages of Double Glazing

During the winter, double glazing is one of the best ways to keep heat in your home. Air conditioning is expensive and wasteful, and it also takes energy to cool down your home in the first place.

That’s why it’s much easier and cheaper to just open the windows and let the heat out. But when the weather starts to warm up, double glazing can make your home uncomfortably hot.

One way to tackle this is to have your double glazed windows tinted, which can help to reflect sunlight and in turn heat, however, this will be an added cost and is not standard.

If air gets into the space between the two panes of glass, it can result in the build up of condensation. These air leaks occur when windows aren’t installed correctly or when they’re repaired and closed up too quickly. Condensation can also occur when there are gaps in the glazing, such as around frames or between double glazed units.

Closing these gaps can help to reduce the build-up of moisture inside the house, which can then be vented out through the windows. Eventually this build up of condensation of water vapour can really impact their aesthetics and make it impossible to see through the window.

However, if you get your windows installed by a professional, this issue is easily avoided and only something you typically see in very old window panes.
Check out our complete guide on the price of new windows, if you want a rough idea of how much you can expect to pay (including installation). You can also read about the various window styles available, as well as double glazing, triple glazing and decorative windows.

Double Glazing Costs

How much does it cost to have new double glazed windows installed in your property? It all depends on the type of windows you choose…

When shopping for double glazing, it’s important to keep in mind how much it will cost to fit the windows. Double glazed windows come in a variety of styles and sizes, so it’s important to identify which will suit your needs and budget best.

It’s also important to consider the type of framing material your windows are made out of, as well as the energy rating of the glass. Double glazing is typically more costly than single glazing, but it can also lower your energy bills and reduce the cooling and heating costs in your home.

In general, the energy efficiency of the glass also impacts the price, with A-rated panes usually costing around 10% more than less efficient ones. However, it’s important to consider the savings this would allow you to make on your heating bills, so it may well be worth it.

How much does it cost to have double glazing installed?

The installation costs is another factor to consider and this largely depends on where you live, since the availability of professionals in your area, as well as other factors can impact the cost. As you might expect, the highest window installation costs can be found in the capital city – London.

As is always advised when considering contracting out work on your home, it’s always advised that you seek quotes from multiple companies. This will enable you to compare prices and ensure you are getting the best value for your money.

uPVC Double Glazing Costs 

Size Price
620x1050mm £140
620x1200mm £150
915x1050mm £160
1200x1050mm £180
1200x1200mm £220
1780x1050mm £280
1780x1200mm £300

Wooden Framed Double Glazing Costs

The exact costs will depend on the style and size of the windows you choose, but you can use the table below as a guide.

Timber Sash Double Glazed Windows

Sash windows tend to be quite tall, with the lowest pane of glass sliding upwards to open. They’re often a striking feature of old buildings, and can provide a huge amount of natural light.

The upper panes of sash windows tend to be fixed, and only the lower pane is meant to be opened. This makes it easier to clean the window, but it also means that light and ventilation are slightly restricted.

If you are considering getting double glazing installed with a sash frame, the usual considerations come into play with regards to price: the size of the windows and floor.

Size Price
600x900mm £1,600 – £1,700
900x900mm £1,750 – £1,800
900x1200mm £1,850 – £1,900
1200x1200mm £1,950 – £2,200
1800x1500mm £3,200 – £3,400

Timber Casement Double Glazed Windows

Casement windows are the most conventional type of window in the UK. Hinged on one side and opening outwards, casement windows are the default choice for many homeowners.

They are versatile and easy to use, and can be opened wide to let in maximum light and fresh air. Because they are exposed to the elements, casement windows also provide excellent ventilation and are a great way of keeping a room feeling fresh and cool in the summer months.

The cost of installing timber casement frames with double glazing will depend on the size and where you want them installed in your property.

Size Price
600x900mm £850 – £950
900x900mm £1,200 – £1,300
900x1200mm £1,300 – £1,400
1200x1200mm £1,500 – £1,700
1800x1500mm £1,800 – £2,000

All of the above prices are for the windows only and do not include the cost of professional installation.

The final cost of installation will depend on the size and complexity of the job. Most projects are done in one day, so you can get an idea of how much an installation will cost before you confirm with your supplier.

Once you’re ready to get your windows installed, your supplier will be able to give you a price quote for the job. You can then choose to go ahead with the installation, or change your mind and keep the windows as a future investment.

What other factors can increase window prices?

The cost of installing double glazing can vary significantly depending on which company you choose to install your windows. While some companies offer incredible value for money, others will try to add as many additional features as possible to increase the overall cost of the project.

It’s essential to remember that there are extra options, provided by numerous double glazing businesses, can push up the cost of a window installation.

For example, upgrading your existing single glazing to energy efficient double glazing can reduce your energy bills and improve the comfort of your home.

The least expensive option is always usually going to be your standard white uPVC framed windows. If you want anything more than that, then you should expect to pay more, here are some of the factors that can influence the cost of a new window install:

Efficiency of the Glass Panes

A-rated windows provide a superior level of energy efficiency over B-rated windows. This means that A-rated windows will perform better than B-rated windows when it comes to keeping the heat in during the winter and the cool air in during the summer.

This also means that A-rated windows will cost more than B-rated windows. However, the energy savings that you will make over the years will more than make up for the higher upfront cost.

In addition to your windows being designed to perform better, having low emissivity (low-e) coatings added to your glass will increase your home’s energy performance by up to 40%. The downside is that this will cost more. 

Window Frame Material

When it comes to choosing the material for your window frames, the price can vary dramatically. For example, aluminium frames could be as much as twice the cost of uPVC.
You may however want to weigh up the pros and cons of each material and see which one best suits your needs. For example, uPVC is a more affordable option, but may not be as durable as aluminium.

How much energy can you save with double glazing?

According to the Energy Saving Trust, the energy savings you can make by installing double glazing (if you currently have single pane windows) can be substantial.

Here are the estimates the energy charity came to, based on average properties in England, Scotland and Wales:

Energy rating Detached Semi-detached Mid terrace Bungalow Flat
A £120-£160 £85-£110 £65-£90 £55-£75 £40-£60
B £110-£145 £75-100 £60-£80 £50-£70 £40-£55
C £110-£135 £75-£95 £60-£75 £50-£65 £40-£50

Please note: it’s important to remember that the savings made from having new double glazed windows installed will take a long time to pay for themselves and so it should be considered a long term investment.

Get a Free Quote for your New Double Glazed Windows Today

The number one advice when shopping for new windows for your home is to secure at least three quotes from local installers.

Your priority shouldn’t necessarily always be price, since the reputation of the company, aftercare and the warranty are also all important factors.

Going for the cheapest may mean paying less upfront, but in the long term you may pay more in terms of time, stress and repairs.

Here at Window Central, we have a network of reliable and trustworthy window installers throughout the UK. Request your free quote now and you should receive a range of quotes from our network in the next 24 hours (at the latest).

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