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Your Complete Guide for Window Replacement: The Ins and Outs

Homeowners love the thought of new, stylish and energy-efficient windows. They hate the cost!

The love/hate relationship is explored in this Window Replacement Guide. The goal is to help you choose windows that you’ll truly enjoy for decades to come at a cost that fits your budget.

What’s In This Window Replacement Guide

When to Replace Windows

If an elephant has sat on your windows – they are falling apart with broken latches, fogged glass, cracked or rotting frames – it is time for new windows.

There are subtler reasons to replace them. One is financial, the other is about creating a home you really enjoy.

  • Inefficient Windows: If they are single-pane or draughty windows, they’re costing you money and indoor comfort through heat loss in winter and/or heat gain in summer.
  • Style you don’t like: Rennovating your home is cheaper and more convenient than selling it in hopes of finding one with more of what you like.

Replacement Window vs New Construction Windows

You’ll hear about this distinction as you shop for windows, so we’ll briefly explain it.

New Construction Windows: When your home was built, new construction windows were used. They have a nailing fin or flange that is used to attach them to the outside sheathing of your home. Then the siding, whether brick, uPVC or something else, was installed.

That nailing flange cannot be removed without removing the siding. If you’re doing a complete exterior makeover with windows too, then new construction windows are an option.

Replacement Windows: If you’re not removing the siding, then replacement windows must be used. First, the parts of the old window are taken out that can be removed while the siding is in place.

The outer frame of the old window remains in place, and the new window is installed within the opening. For this reason, replacement windows are also called retrofit windows.

When you Can’t Use Replacement Windows: If the original windows are wooden, and the timber is rotting, then they have to be entirely replaced.

Replacement Window Material – Costs, Pros & Cons

There are many good choices for material. This table is an overview. Each is discussed below.

Prices are for double-hung windows and include installation.

  • Cost for fixed windows are slightly less, unless they are very large fixed/picture windows.
  • Cost for casement and awning windows are slightly higher.
  • Bay and bow window assemblies can cost two to three times standard windows.
Material Low (1) Average High
Wooden £550 – £750 £750 – £950 £950- £1,500+
uPVC £225 – £450 £450 – £675 £675 – £1,000+
Aluminium £250 – £490 £490 – £700 £700 – £900

Window Cost Factors for All Materials

Factors for all windows include the size, glass package, hardware choice and special accessories like between-pane blinds.

Wood Windows

The natural beauty of wood is unsurpassed. It is the top choice for homes with traditional architecture, but some wooden windows like the Anglian Wooden Casement windows have modern styling.

Wooden Window Replacement

Types: Most styles are made: Sash, casement, tilt and turn, shaped and bay.

Wood Window Cost: Wood windows are available in mid-grade to premium, with a cost to match. There are no cheap wood windows. The cost of wooden windows installed starts at about £300 for small, fixed windows. Average costs for all styles are £750 to £950 with VAT included.

Pros and Cons
Homeowners take both the good and the bad into consideration when choosing wood windows.


  • Natural beauty
  • Good range of softwood and hardwood materials
  • The most options for hardware, grilles and colours
  • Stained, primed and bare wood options
  • Multiple frame configurations to choose from
  • Some wooden windows, like Marvin AluClad windows, feature aluminium cladding on the exterior for greater weather-resistance and lower maintenance


  • Higher average cost plus the highest cost for premium windows
  • Greater maintenance requirements for wood exteriors
  • Shorter warranties on most wooden windows compared with uPVC

uPVC Windows

The best-selling windows are uPVC. The material is appreciated for its value – affordability combined with durability. Styles range from traditional wood-window look to sleek, contemporary windows.

UPVC Windows Replacement

Types: UPVC windows come in every type including sash, cottage and casement.

uPVC Window Costs: Quality ranges from cheap uPVC windows to those with excellent design and build. Installed costs for double glazed windows starts below £250 for small, fixed windows. The average cost for the most common types and sizes is £325 to £625, though some prices are higher.

Pros and Cons
We’ve mentioned value as an advantage. Here’s the full list.


  • Excellent durability in mid-grade and premium uPVC windows
  • Lifetime warranties for some
  • Maintenance-free exteriors
  • Energy-efficient windows when the frames are insulated (most common)


  • Not as good-looking as stained wood
  • Fewer colour and style options compared with premium wood windows
  • Environmental impact is higher than with other materials

Aluminium Windows

Aluminium windows have one “con,” but it’s a big one depending on where you live.

Slimline Aluminium Windows

Types: They’re available in the most window styles – sash, casement and more.

Cost of Aluminium Window: Installed cost begins as low as £185 and rises to about £1,000 for the largest windows.

Pros and Cons
Your options go way beyond bare, gray aluminium sliding windows.


  • Lightweight, so easy to handle and install
  • Available in 50+ coated colours
  • Good strength and durability
  • Affordability


  • Poor energy efficiency, so they are rarely used in cold climates – in fact, they should not be considered where winter temperatures dip below freezing or your energy costs will rise

Replacement Window Types

Here are the types or styles available and their pros/cons and best uses. But first, here’s a table of window costs by type:

Window Type uPVC Aluminium Wooden
Shaped/Fixed £180 – £600 £195 – £665 £335 – £1,000
Sash £225 – £800 £240 – £885 £485 – £1,200
Tilt and Turn £300 – £750 £350 – £800 £550 – £995
Casement £315 – £900+ £365 – £1,000+ £580 – £1,100+
Bay £1,150 – £2,500+ £1,200 – £2,700+ £1,500 – £3,300+

Fixed/Shape: These windows don’t open, so there’s no ventilation option. However, they are affordable and offer an unobstructed view. They work well in an assembly between functional windows like casement or sash windows or when placed near the ceiling in a two-story area or a cathedral ceiling peak.

Sash: These very popular windows are found in almost every line of windows from all brands. On many sash windows, the sash opens in for easy cleaning. The only “con” is that the sash frames obstruct the view.

Tilt and Turn: These also offer easy cleaning and good ventilation without the view obstructed.

Casement: Also hugely popular, casement windows offer unobstructed view. They’re available in all materials. The biggest negative is their higher cost than sash windows.

Bow: While pricey, these window assemblies add style and natural light to any setting.

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Glazing: The Importance of Window Glass

Single Vs Double Glazing

In window lingo, the glass package for your windows is called glazing.

Double-glazed, Low E: The most common windows feature are double-glazed, meaning two panes of glass, and the glass is low E. That means low emissivity. A thin coating is applied to the glass to reflect long-wave infrared energy, commonly called heat. This makes the windows energy efficient.

Argon: Many double-pane windows also have argon gas between them to boost their resistance to heat transfer. Triple-glazed windows are available in some lines that offer premium insulation and better sound control.

Options: Additionally, you have options such as shatter-proof or tempered security glass, obscure glass for privacy, etched for beauty and tinted glass for light control. There are typically more options for popular and high-end window series.

Top Replacement Window Brands

There are quite a few very good window brands.

While it is impossible to do the list justice in this Window Buying Guide, here are top window brands to consider when shopping.

Some of these brands make multiple series of wood, aluminium or uPVC windows. This allows you to shop within your budget and the style that best suits your home’s architecture.

Anglian Andersen Euramax Everest Marvin Wickes Wright
Wooden £460 – £1,600+ £475 – £1,725 N/A £415 – £1,585 £445 – £2,000+ £440 – £1,275
£400 – £1,700
uPVC £190 – £1,100 £225 – £1,275 £210 – £1,185 £200 – £950 N/A £250 – £695
£230 – £1,250
Aluminium £225 – £1,235 £250 – £1,300 N/A £225 – £1,050 £275 – £980 N/A
£310 – £1,350

DIY Window Replacement

In the cost/benefit analysis, we recommend using a professional installer. Of course, if you’ve installed replacement windows before and were successful, have at it.

By DIY, you’ll save £60 to £150 per window depending on size, type and how easy it is to remove the old windows.

It’s a challenging task – to get out the old window without damaging the frame, and then installing the new window so that:

  • It is as airtight as possible for energy efficiency
  • Is straight, so that it will open smoothly and not be subject to torque that might cause the frame to warp or crack

If you do it yourself, watch tutorials from the manufacturer. And follow their installation guidelines exactly. If you don’t, the warranty might be voided.

Choosing a Window Installation Company

If you decide to have the windows professionally installed, hire a company with a good reputation for craftsmanship and customer care.

Windows Installation Company

We highly recommend asking quotes from at least three local window installers.

  • Find out how long they’ve been in business, and choose one with 5+ years of experience. A decade or longer is better. It shows they’ve got what it takes to do the job right the first time.
  • Ask about the experience of the tradesmen that will be installing the windows. That’s what really counts. If they’re new on the job, look for another installer.
  • Ask about their window guarantee. Will they fix a window that wasn’t properly installed in a year? Five years?
  • Look at reviews from others that have hired the company. Are they rated high or low?
  • What you discover will guide your decision about hiring.

Tips for Saving Money on Window Replacement

The best option is getting estimates from several companies that know they are competing for your business.

Beyond that:

  • Choose uPVC instead of wood to save 30% to 50%.
  • Choose more affordable hardware and accessory options.
  • Choose a more affordable line of any material you choose.
  • If you want wooden windows, choose all-wood exteriors rather than clad exteriors, but be prepared to spend more on maintenance if you stay more than 10 years in that house.
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Frequently Asked Questions when Replacing Windows?

  • Q. How long do uPVC windows last?
  • Ans. Typically lasting around 20 years, which can vary between 10-35 years depending on the quality of the window and upkeep.
  • Q. What Does uPVC Stand For?
  • Ans. uPVC is an abbreviation for an unplasticised polyvinyl chloride which is commonly used within window frames.
  • Q. What is double glazing?
  • Ans. A double glazed window consists of two panes of glass which are separated by a small cavity which is filled with an inert gas, usually Argon or Krypton. This gas reduces the amount of heat that is able to escape through the window, therefore making your home more energy efficient.
  • Q. What is triple glazing?
  • Ans. Triple glazing works in the same way as double glazing, but there is an additional pane of glass and an additional cavity filled with Argon or Krypton. This improves energy efficiency and also improves acoustic insulation and security.

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