How much does it cost to fit new windows?

The average cost of supplying and fitting a standard uPVC double-glazed window is £400 - £600

Low cost
Average cost
High cost
How much does it cost to fit new windows? graph showing high and low prices for a standard window

Things to consider

  • What type of windows will be most suitable for your home?
  • What benefits are there to upgrading your glazing?
  • Do you need planning permission?
  • Does your tradesperson require FENSA or Certass accreditation?
  • Could you replace a double window with double doors?

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Fitting uPVC windows – what you’re paying for


When you’re buying new windows, you’re paying for much more than just glass. You’re improving your home’s security, upgrading its thermal insulation, blocking out unwanted noise, or simply adding that perfect finishing touch to your own grand design.

The cost of fitting new windows hinges on a number of factors, including the size of the window, the style or design you choose, and the depth of the glazing. Window fitters and conservatory installers can help you determine the right option for your home and your requirements – so, it’s worth drawing on their expertise.

When it comes to conservatories, it’s easy to dismiss them as a luxury reserved solely for the summer months. But most modern options are so well-insulated and efficient that you can use them all year round – making conservatories a worthwhile investment if you need more space. They’re often less hassle (and can be more attractive) than a standard extension too. A conservatory specialist will be able to recommend the type of structure that’s right for your home, so pick their brain to understand the key differences between the available options.


How much do uPVC windows cost?


The average cost of a standard sized double-glazed uPVC window installation is £500.

Modern uPVC windows are stylish, affordable and efficient. The right type of window will ensure you benefit from impressive insulation standards.

When it comes to finding the right tradesperson for the job, ensure they hold FENSA or Certass accreditation. They are organisations responsible for regulating double glazing sales and installation, and all uPVC window or door fitting professionals should be registered with one of these competent person schemes.

The cost of new uPVC windows largely depends on whether you’re after a small window with a basic design or lavish alternatives with stylised features like sash windows.


How much do sash windows cost?


The average cost of a medium-sized sash window is £675.

This classic window design has been around for centuries. Sash windows open vertically by sliding upwards, rather than opening outwards on a hinge. As well as providing a distinctive design feature – well-suited to period properties – sash windows can be a practical choice in certain circumstances too, as they’re also more compact than some alternatives.

The materials that sash windows are made from affect the cost. Timber is the traditional choice, but uPVC is a cheaper modern alternative. The latter can be made with slimmer frames compared to wooden options, providing a neater and less bulky look. And it’ll require next to no upkeep as well. The different size and finish (white or woodgrain effect) you opt for will steer the price of your window, with smaller, plain styles coming in at the cheaper end of the scale.


How much do bay windows cost?


The average cost of a standard uPVC 3 panel bay window is £1,200.

Bay windows project outwards from the exterior walls of your home, giving you additional space in your living room, dining room or study. That metre or so of extra depth in a room can come in handy, used for a desk or as a seating area.

There’s a wide array of designs and materials to choose from, and that means there’s a similarly broad range of prices to fit bay windows. The bill very much depends on the size of the frame and what it’s made from, along with the type of glazing you choose. But there are options available to those on a more modest budget, and you can cut costs by using uPVC windows instead of timber or aluminium alternatives.


How much do Velux windows cost?


The average cost of a Velux window is £900.

You might be looking to fit a Velux window for style, for practicality, or for both those reasons. Skylights and Velux windows are a functional solution for loft conversions or chalet bungalows, but these windows can also be a classy finishing touch to increase natural light when used in a kitchen extension.

Installing a skylight or Velux window won’t faze an experienced window fitter, but they will usually involve more work than a standard glazing unit. This is mainly because – unless you’re replacing an existing Velux – a small amount of demolition work will be required to cut into or knock through your roof and then install any required supports for the roof timbers. Fitting the window itself is then a fairly straightforward process.

The overall cost of the job will mainly depend on the design of the Velux you go for, as well as the size of the window. Costs can go up if you choose a large, expansive skylight window.


How much does a conservatory cost?


The average cost of supplying and fitting a small uPVC conservatory (2.5m x 2.5m) is £10,000.

You won’t usually need planning permission for a conservatory or an orangery. That’s because you’re allowed to build a conservatory provided it’s no more than 50% of the size of your house, it’s not over four-metres tall, and it doesn’t have a veranda, balcony, or any other elevated platform. There are a few other restrictions for specific properties and those bordering public highways or other structures – find out more on the planning portal.

Both orangeries and conservatories are typically cheaper to construct than single-storey extensions. The difference between an orangery and a conservatory comes down to how the roofs are built and the arrangement of brickwork used. Orangeries tend to have less than three-quarters of their roof glazed along with solid brick walls. Conservatories, on the other hand, usually have the entire roof and most of their walls glazed. An orangery can cost more than a conservatory to build, but you’ll save on heating costs in the winter months, as there’s less glass.


Appendix – Costs

Low Average High
Standard uPVC window installation costs
Supply and fit uPVC window (100cm x 100cm) £400 £500 £600
Supply and fit uPVC sash window (100cm x 100cm) £625 £675 £725
Velux window installation costs
Supply and fit small window (66cm x 98 cm) £750 £900 £1,200
Conservatory installation costs
Supply and fit small uPVC conservatory (2.5m x 2.5m) £5,000 £10,000 £15,000
Supply and fit large-sized uPVC conservatory (5m x 5m) £15,000 £20,000 £30,000
Supply and fit medium-sized orangery (5m x 5m) £19,000 £30,000 £44,000

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