Double Glazing & Window Replacement Costs: 2021 Price Guide

The Bottom Line:

uPVC is the cheapest option when replacing any windows, followed by aluminum, which typically costs 20-30% more with wooden timber frames being the most expensive option. 

Whilst timber frames can add significant value to a property they require maintenance whilst uPVC and aluminium framed windows require much less. 

Triple glazing is around 30% more expensive than double glazing but will provide that extra level of thermal efficiencies meaning that saving will be made back over time. 

The more windows and doors you order from a company the greater the likelihood of a discount. It can therefore be more expensive to replace windows individually than all together. 

Average prices for a window (600*900mm) in size: 

  • UPVC – £300-£400
  • Aluminium – £500-£700
  • Wood/Timber – £650-£950

Average Window Replacement Costs

Prices for a Full Property & Per Window

Costs to completely replace windows and doors are of course dependent on how many you have but a good starting guide based on the average 3 bed semi detached is between £2500-£7500.

The lower end of that estimate is if you have fairly standard windows and the higher end is if you are replacing french doors and/or any sash windows.  

 Average replacement costs for a standard size window is £300-400. Doors are of course slightly more at around £500-£700. That’s for single doors, like a standard back door. All prices referred to in that description are for uPVC windows.

Bay Windows

Bay windows are fantastic for creating lots of light in the room, optimising space and creating huge amounts of curb appeal.

What does a bay window cost to fit?

See the uPVC bay window estimates below for each size [fitting inc]:

£1200/£1400 – 2.4m*1.2m – 3 Section Bay Window

£1800/£2000 – 3m*1.2m – 4 Section Bay Window 

£2200/£2800 – 3.6m*1.2m – 5 Section Bay Window

Sash Windows

Sash windows are the style most typically found on Georgian and Victorian houses. They are normally made with timber frames to remain in keeping with the property, but can be made from composite or uPVC. 

They give an elegant look to the property and enhance period features. They are normally quite large windows opening vertically or horizontally, allowing maximum light into the room. Excellent then for a bedroom, office or any living space. 

Costs for replacement Sash window are estimated below:

A 1m*1m Sash Window costs £650-£750  

Window Panes

Double vs Triple Glazing

Double glazed is now standard with most new window manufacturers actually being known as ‘double glaziers’. 

However for extra warmth in the winter don’t rule out triple glazing. Whilst it is normally about 25-30% more expensive than double glazing, those costs could be recouped in energy savings very quickly and it will definitely future proof your house. It’s certainly something to consider. 

Once you have decided on double or triple glazing, the next choice are the glass panes. You could have clear transparent windows as standard and the ideal choice for a bathroom and windows on the side of any property is frosted glass for complete privacy. 


Then the other options you have are lead windows. You typically see these only on the front windows of houses and not always the rear, due the cost. It gives a Georgian feel to the property and can improve the curb appeal of your property.  

Stained Glass

Last but no means least are stained glass windows, which have become very popular again offering a special way to make your windows and home truly unique. They offer all the same features as the other styles but will shower your home in lovely colours as the sun shines through them. Non transparent stained glass windows make excellent bathroom windows for creating privacy and ambience. 

Did you know….. you can create your own stained glass effect with ordinary windows by using a stick on film? It’s cost effective and if you decide you don’t like it after, you can simply peel it off. 

UPVC, Aluminium & Timber Price Differences

uPVC or PVCu are the same thing spelt differently. Or to give it its full name Unplasticised Polyvinyl Chloride’, so don’t let any company tell you different or try and fool you with industry jargon.

uPVC is great for window frames as it’s ridged, resistant to any corrosion and doesn’t rot.   

This is the cheapest option when considering new windows and doors and they can be made in a variety of colours to suit all homes.


Another option is aluminum, it’s lighter, stronger and lasts much longer than wood, requiring little to no maintenance. The window frames are also thinner taking up less space and when directly compared to uPVC are more thermally efficient. Like uPVC aluminium frames can be made in a number of different colours to match the look of your home. 


Whilst they are the most costly option and can require maintenance in the form of painting or wood preserving, timber frames are an excellent choice in period houses or houses with lots of character. They have a timeless classic look and are seen by most as an investment in your property. Adding wood framed windows can drastically improve the value of any home. 

Where to Get Window Replacement Quotes?

Whatever you do, the standard rule of thumb is to obtain 3 quotations before commencing any work. These should be written quotations from companies or individuals. 

One or two of those quotes could be from large nationwide companies like Everest or Safestyle and the remaining quotes from perhaps a local company. This will give you the best gauge on pricing and help you make that all important decision. 

Whilst websites like ‘checkatrade’ have made it easier to find reputable and trustworthy window manufacturers and installers, it still can be a hassle. Alleviate some of that hassle by obtaining a quotation for new windows and doors by going online and receiving several quotes at once. This saves so much time as you haven’t got to be at home waiting for someone to come round each time you want a quote. 

Doing it online means you have several quotations to choose from and can go with the one that best suits you.   

Window Replacement Costs FAQ

How do I find a window fitter near me?

If you decide to accept a quote from a manufacturer for just windows and doors excluding fitting then you will have to find someone yourself to fit everything. Often the manufacturer of the windows can recommend people or companies, so be sure to ask.

Again obtaining quotes for fitting is just as important as getting quotes for the windows themselves.

Use google and be sure to check reviews of window fitters.  

Should I replace all windows at once?

Most people replace all the windows at once if they are all of a similar age for longevity and also to complete the look of the property. One un-matching window can spoil the whole effect.

However you might decide to replace the front and back separately. The advantages of this is it splits the cost but the disadvantages are they might not look exactly the same.

Bear in mind too that most companies will offer discounts for the more windows you order. So it’s generally always cheaper to replace all the windows and doors you can at once, than a few at a time.    

In Summary

  • Obtain 2-4 written quotes 
  • Colored frames will absorb more heat and could therefore degrade more quickly
  • Clarify if there is VAT on any of the prices
  • Does the price include removal and disposal of your old windows