Double glazing has been around for years, but recent innovations have helped bring superb A, A+ and even A++ energy-rated windows to the market.
However, not all double glazed windows are built to the same spec, and older windows from the 80s, 90s and early 2000s likely need replacing. Double glazed windows don’t last forever – especially not the older models.
Replacing your old double glazed windows with modern windows will yield massive energy savings over time, boosting the value of your home in the process.
This article will review the average cost of double glazing in the UK, factors that affect the cost and other common questions around double glazing.
Average Cost of Double Glazing
The following costs are for different types of materials. They include the supply of the window, plus the fitting. Generally other prices you see on websites are cheaper because they only include supply costs.
The prices below include removing old windows and disposing them. If there are multiple jobs happening (e.g patio doors), then this will affect the prices below.
Average UPVC Double Glazing Cost
| Type of Window | Average Cost |
|---|---|
| Casement | £475 - £1,200 |
| Sash | £720 - £1800 |
| Tilt & Turn | £540 - £1350 |
| Bay Windows | £1200 - £3000 |
Average Aluminium Double Glazing Cost
| Type of Window | Average Cost |
|---|---|
| Casement | £600 - £1,500 |
| Sash | £890 - £2,250 |
| Tilt & Turn | £670 - £1,700 |
| Bay Windows | £1,500 - £3,750 |
Average Timber Double Glazing Cost
| Type of Window | Average Cost |
|---|---|
| Casement | £720 - £1,800 |
| Sash | £1,070 - £2,700 |
| Tilt & Turn | £800 - £2,025 |
| Bay Windows | £1,780 - £4,500 |
Factors that Affect the Cost
The costs above have quite a large range since there are multiple factors that affect the cost.
Size
The larger the window, the higher the cost.
Number of Windows
The more windows you have installed, the cheaper the cost per window price.
Type of Glass
Be sure to check the thermal efficiency and air leakage values when choosing new double glazing. An A++ window rating is the highest rating and can be a good investment if you want to lower bills.
Double glazing with high energy efficiency ratings will cost more. For example, A-rated glass can add 10% to cost compared to installing B-rated glass.
There also also various glass types like toughened, self-cleaning and frosted. These have different characteristics and their cost will vary depending on the supplier.
Ground Floor vs Upper Floor
Double glazing on upper floors will cost more as the installer has extra logistical issues and will need to use scaffolding in order to undertake the work safely. This can add anywhere around £60+ per window.
Colour
White UPVC is the most common and cheapest colour. However, frames can be finished with a variety of colours such as rosewood, oak, grey, cream or black.
Certain colours as often considered ‘premium’ and will cost more than the standard white. Expect to pay a little more for these rarer colours.
Location of Supplier
If you use a company near you, then there shouldn’t be any additional costs to supply or fit your double glazing.
However, if you use a company much further away, then may add extra costs depending on which delivery zone you fall under. Check the company’s website for their specific costings.
Supply prices are generally similar throughout the UK. However, if labour costs will vary throughout the country. Expect to pay on the higher end in south east England and London.
Types Of Windows
There are quite a few different types of windows. The most popular are:
Casement
A typical window with a hinge that opens outwards. A uPVC window measuring roughly 600 x 1,000mm costs around £200 to £300 in supply costs. Casement windows are the cheapest and most common type of window. Suitable for most properties.
Sash
A vertical sliding window, most associated with character and period properties. A vertical sash window measuring roughly 600 x 900mm costs around £400 supply-only. Sash windows are marginally more expensive than casement windows. They take up more vertical space but are often narrower than casements.
Tilt and Down
Open in the same way as casement, but can also be tilted backwards as ventilation. The most expensive option of the typical window types. A tilt and turn uPVC window measuring roughly 600 x 1,000mm costs around £400 to £500 to supply. Tilt and down windows cost 10% to 20% more than casement windows.
Sliding
A sliding window that opens horizontally; typical in kitchens. A sliding window measuring roughly 1,200 x 2,400mm costs around £700 to £800 to supply. Sliding windows are somewhat of their own category.
Bay Window
A 3D window consisting of three windows slotted together, thus forming a bay in the room. A 3-piece bay window measuring roughly 1,200 x 2,400mm costs around £900 to £1200 to supply.
Bay windows are somewhat of their own category, but they cost significantly more than casement windows.
Types of Window Frame Materials
There are four main types of window frames to consider:
- uPVC
- Aluminium
- Steel
- Timber
uPVC
uPVC is the most popular type of window frame material. While uPVC is generally assumed to be white, it’s now possible to buy grey, black or even wood-grain uPVC windows to suit any home.
uPVC is super-durable, light, strong and boasts excellent thermal performance. It’s also become more environmentally friendly over the years.
uPVC windows are the cheapest, most widespread windows around. They’re readily available and come in loads of styles.
- The cheapest, most popular window frame
- Loads of designs available
- Can get white, black, brown or wood grain frame
- High performance for an excellent price
Steel
Steel is strong, durable and looks neat and modern. Steel windows are popular for modern properties that wish to maintain a modern or chic industrial aesthetic.
Though heavy, steel windows are long-lasting and aren’t too much more expensive than uPVC
- Look great and very strong
- Slim frames for maximum light
- Suit modern houses
- Lots of colours available
Aluminium
Moving up a notch in terms of price, aluminium double glazed windows are slim, strong and look great. Aluminium windows suit modern properties that wish to retain a sleeker or minimalist exterior.
Of course, aluminium windows also boast excellent thermal properties. Aluminium windows are more expensive than uPVC and a similar price to steel.
- Ultra-slimline
- Excellent for modern properties
- Superb performance
- Lots of colours available
Timber
The most expensive option. Timber double glazed windows look superb – they’re the real McCoy for rural, period or characterful homes, or anyone looking for a more natural aesthetic. Timber is environmentally friendly, strong and durable.
Timber windows are treated against rot and fungus and last as long as other types of windows. The catch is; you really do get what you pay for when it comes to timber windows – look for proven brands with guarantees rather than the cheapest.
- Natural finish
- Durable and strong
- Excellent thermal performance
- Best aesthetic qualities for certain houses
Should I Install New Double Glazing?
Double-glazing performs for some 15 to 25 years, though newer windows likely last longer. So, if you’ve not replaced your double glazing in the last 20-years or so, it’s quite likely degrading.
While window degradation is slow, feeling a draft near your windows, or seeing the curtains move during high winds, is a sure sign that your windows are not well-sealed anymore. This will decrease a home’s energy performance, and bills will climb.
Installing new double glazing is an excellent way to reduce energy bills. According to a government study, installing A-rated double glazing in a home will save £80 to £110 in a semi and £120 to £155 in a detached house.
Benefits of Installing New Double Glazing
There are many benefits to installing new double glazing
Reduced Energy Bills
Double glazing reduces energy bills, often to the tune of thousands over a 10-year period. Quality double glazing is the backbone of a well-insulated, energy-efficient home.
Boosts Home Value
Double glazing boosts home value by some 10% compared to single glazing. That may seem extreme, but bear in mind that few homes are single glazed now. If your home is single-glazed, installing double glazing should be a serious consideration.
More Secure
Modern double glazing is exceptionally strong. There is no comparison to single glazing in terms of safety and protection from break-ins.
Fewer Drafts
Drafts are unpleasant and seriously compromise heating performance. Old double glazed windows are a common culprit in drafty houses. Swapping out for double glazing will reduce drafts (doors do also make a big difference).
Sound Insulation
Quality sound-proof windows make a huge difference in noisy areas. This makes houses built next to railways, motorways or even airports much more sellable.
Most of the main brands such as Anglian, Everest and SafeStyle provide dedicated double glazing models for sound insulation.
Does Double Glazing Increase Home Value?
While double glazing salespeople won’t have to think twice before answering this, the answer genuinely is yes. Estate agents reported to This Is Money that installing double glazing can boost a home’s sale price by some 10%.
“We’ve sold an Edwardian terrace cottage for £40,000 more than predicted two years ago. All the owners did was replace single-glazed windows with wooden framed double-glazed windows costing £18,000,” – This Is Money.
Of course, the value of replacing windows is additional to the value you’ll extract from your windows by reducing your energy bills.
Does Double Glazing Lower Bills?
Double glazing and insulation is the best way to insulate homes and reduce bills long-term.
Government data suggests that installing double glazing in a single-glazed house will provide the following yearly savings:
| Energy Rating | A | B | C |
|---|---|---|---|
| Detached House | £120 - £155 | £110 to £140 | £105 - £135 |
| Semi-Detached House | £80 - £110 | £75 to £100 | £75 - £95 |
| Mid-Terrace House | £65 - £85 | £60 to £80 | £60 - £75 |
| Bungalow | £55 - £75 | £50 - £70 | £50 - £60 |
| Flat | £40 - £55 | £35 - £55 | £35 - £50 |
As we can see, savings are not huge but they are considerable. Over 20 to 25 years, savings in energy bills will pay off a considerable portion of the initial outlay of buying double glazed windows.
Window Energy Ratings
The energy rating system helps consumers work out the energy performance of a product. It’s represented by a scale of A++ (the best) to E (the worst).
You see this scale on all sorts of products these days, ranging from electronics to insulation and windows.
Current UK Building Regulations require all newly fitted double glazed windows to be at least C-rated. There shouldn’t be any window rated below C on the market today.
Most well-known double glazing brands such as Anglian, Everest and Safestyle are very upfront about their energy ratings, and some provide their own measures that go beyond the standard scale.
The cost of A++ windows is not much more than A or A+. It’s worth opting for A++ if possible, as they’ll definitely provide superior thermal performance to anything you have now.
A++ windows are a good marketing angle if you ever sell your home.
Things to Consider When Considering Double Glazing
- Stick with white, uPVC, double glazed A-rated glass if you want to get the best price possible. Extra colours, finishes and other bells and whistles will add extra cost.
- You may be able to just replace glass only if you’re remedying an existing issue. Sometimes if you have steamed up windows, you don’t need to replace the whole window, just the glass itself. This will be considerably cheaper.
- Ensure you compare like-for-like windows. Be sure you’re getting the specifications that you want so that any comparisons are made accurately.
- A surveyor will most likely need to measure your windows before fitting. The vast majority of double-glazed windows are made bespoke. Normally only new-builds can use ready made windows.
- Consider the differences between working with a local vs national installer. National installers work in partnership with large double glazing companies, who have many local installers on their books who they will put you through to. You can also go direct to a local glazier, which will most likely be cheaper, sourcing your chosen windows and installing them for you.
Glaziers should have a strong local portfolio of successful work and accreditations from their suppliers. Be sure to check any guarantees on your chosen windows too.
Accreditations to look out for include:
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