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What is the Average Cost of Double Glazing?

Whether you are installing new windows or having the existing ones on your house replaced, it is useful to get an idea of what the average cost might be.

Of course, price will vary greatly depending on the area you live in, the types of windows and frames you choose, the amount of windows you have fitted, and the style or features that you want integrated into the design.

The average cost of Double Glazing

The average cost of installing double glazing is around £300-£400 per standard casement window

The average cost of installing double glazing is around £300-£400 per standard casement window

To make things more confusing there are also hundreds of different suppliers and fitters, ranging from large national companies to local independent firms, each of whom will offer greatly different prices.

In general, the typical cost of a double glazed window will be around £300-400 fully fitted. Whatprice.co.uk website places the cost at an average of £387, based on eight windows being fitted.

There are many variables which will affect price, however, which we will look at in further detail below. Anything from the size of the windows, the material used for the frames, the type of window, or even the type of property can have an impact on the quotes you will receive.


How do different styles affect cost?

Different styles and designs of window will inevitably have an effect on the cost. While a typical casement type double glazed window may cost around the £300-400 mark, tilt and turn windows can cost around an extra 30% per unit.

Sash windows are typically more expensive to replace, Whatprice.co.uk places the cost of converting to double glazing at £450 per window, while renewing the window can cost up to £1000.

The material used for frames will also be a factor in the final cost. Timber frames can be the cheapest, but not always the most durable.

Restrictions on listed buildings may insist on the use of timber frames, and there are various hardwood frames available, although these are much more expensive.

The most popular choice of frame, UPVC, is less expensive and generally one of the most reliable types of frame.

Aluminium, on the other hand, is considered the most durable type of frame, but again, this is reflected in the price as they are one of the most costly types.


What about features?

Any extra or bespoke features put into a window will increase the cost overall. Stained glass windows, for example, may cost up to £30-60 per square metre of glass.

Any other variant on standard designs will also cost extra, be it frame colour, internal beading or toughened glass; while ‘A’ rated windows will also be more expensive.

Other features and benefits to look out for which will also affect the price are things like a low U-value, extra security systems and multipoint locking mechanisms, trickle vents, and the type of gas used to fill the cavity between panes.


The effect of large or small windows

Clearly the size of the windows will have a bearing on the price, although it is difficult to put a figure on the amount per square metre, or per the size of the opening.

Usually getting a quote will require a surveyor coming to the property to take measurements, and the quote will be based on the total number of windows as well as the size of each of them, and the materials to be used.


Are there discounts available for several windows?

Most companies, whether national or local organisations, will offer discounted prices if you are having more than one window fitted. In this respect it makes sense to have the whole house done in one go, rather than having windows done individually as and when needed.

Some leading national companies’ make a point of their ‘buy one get one free’ offers when it comes to windows, and all of them will offer greater discounts the more windows you have fitted.

Signing a contract for Double Glazing

Before signing a contract always get more than one quote for Double Glazing

Don’t be frightened to ask for these discounts either; the double glazing industry has a reputation that we are all aware of for dubious sales tactics, whether justified or not.

It is always worth pushing any quote down as low as you can through negotiation; most suppliers set their prices in the full knowledge that they will be heavily discounted.

How do I find the best value

The best way to get the best deal for your windows is to shop around; just like you would with any other purchase. Arrange quotes from a few different companies to compare, and knock each one down as far as you can.

Never reveal to one company what another has quoted, you will instantly give them the upper hand as they will know what they are competing against.

Remember that price isn’t everything; make sure that the company you use is reputable, and has been in business for several years at least.

Ask them for the addresses of local jobs they have done so you can assess the quality of their work; if they are proud of their work and reputation they will have no hesitation in providing you with the addresses.

Lastly always check that the products and the workmanship come with a long guarantee, to protect your investment against the use of inferior products or shoddy workmanship.



It is difficult to nail down typical costs for double glazed windows as there are so many different companies offering such a wide range of different products.

While the standard price of a casement type double glazed window is estimated at around £300-400, this figure is entirely variable based on the area the house is in, the design of the window, the material used for the frame, the cost of the fitting and so on.

What the price does do though, is give you a ‘ballpark’ figure; it is incredibly difficult to obtain rough prices or estimates from double glazing companies, as inevitably they will want one of their sales people to visit you.

This is understandable, as they will view any enquiry as a sales opportunity. However, armed with this rough cost, and with several quotes to choose from, you will be in a position to make a well educated decision on the company you use, and the windows you have fitted.

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