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How much do UPVC Sash Windows Cost?

Sash windows are a classic type of frame that works perfectly in period homes and heritage properties - a modern UPVC replacement will cost an average of £700 to £1,100 per unit.

This reparatory work can make a considerable difference to the value of your home, particularly if you're replacing old draughty sashes with a contemporary upgrade, complete with double-glazing.

Looking for an accurate cost of UPVC sash windows? Fill out the form below and we'll put you in touch with local window fitters in your area - compare costs for free! Time complete - 30 seconds. 

Part of the appeal of UPVC windows is that they are the most cost-effective option and require minimal maintenance while lasting for years. Timber sash windows are available but have a higher price point and need to be repainted or stained periodically to prevent dampness and rot.

Today we'll look at the average UPVC sash windows cost and the elements that will have the biggest bearing on your budget.

Factors That Impact the Average UPVC Sash Window Cost

UPVC is affordable and widely available from window fitters across the UK.

A sliding sash window can cost as little as £500 to £800, depending on the size of the opening and whether you want a normal white UPVC or a wood effect finish.

Below are indicative costs based on some of the standard sash window sizes.

Window type Average cost per window
White UPVC sash 50 cm x 50 cm £520 - £625
White UPVC sash 100 cm x 50 cm £600 - £720
Wood effect UPVC sash 50 cm x 50 cm £625 - £720
Wood effect UPVC sash 100 cm x 50 cm £700 - £800

Sashes usually comprise two separate glass windows, each made from energy efficient double glazing.

The typical function is that one pane will slide up and down to open or shut the window, although you can order a sash with two sliding parts.

Single sashes refer to the option where the upper panel is static and the bottom panel moves. Double-hung sashes have two moving panels and are a little more costly.

If you opt for timber, the average cost per window increases to around £1,100 to £1,900.

Many homes built during the 1700s and up to the early 1900s have sashes, but a UPVC sash can look just as stunning on modern properties but in a traditional style.

The Energy Savings Trust predicts that the average home would save at least £115 a year by replacing single-glazed sashes with insulative double-glazing.

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Additional Considerations in Fitting UPVC Sash Windows

As we've discussed, multiple variables will affect your overall sash window replacement cost.

One is whether you decide to restore an older sash window or replace it altogether.

The issue can be that older properties may require more extensive work and preparation, particularly if the old frame is a non-standard size or the brickwork around the window needs repairs.

Restorations can be significantly more expensive than a replacement, with average costs from £300 to £2,000 per window. Usually, the most costly sashes to fix are very old windows with leaded bars running across the glass.

A full window restoration also takes much longer than replacing an old glazing unit with a new frame. This option is often necessary for listed buildings or properties in conservation areas where you are not permitted to fit UPVC glazing.

Below we'll look at some of the other cost factors, in turn, to explain how they will impact your quotations.

UPVC Sash Window Weights and Sizes

Sash windows come in various sizes and weights, so a larger window with a heavier frame and on an upper floor in your home will inevitably cost more to install.

Glazing installation costs include:

  • Materials - including the UPVC frame and double-glazed glass.
  • Installation costs - including removal of the old window.
  • Waste removal - often requires a skip if you are replacing more than one window.
  • Scaffolding - necessary to reach higher windows above ground floor level.
  • Repairs - window fitters may need to plaster the wall around the window or undertake other decorating work to make good on the finish (although not all will offer this service).

Larger, heavier windows will need two or more tradespeople to lift the unit into place, so you would normally expect to pay higher labour costs and higher material costs.

The heavier the window, the more the work will cost since the supports required need to be stronger and robust enough to sustain bulky glazing materials for the years to come.

UPVC Sash Window Glazing Options

Next, you'll need to choose the type of glass you'd like. Our average costs assume you are using double-glazing, but there are plenty of other options.

Laminated safety glass is toughened, ideal for ground floor windows with a security or breakage risk and families with pets or young children.

Acoustic glass is also a premium option but is thicker and heavier to protect your home from external noise disturbances.

The extra price may be worthwhile if you live close to a high-noise motorway, airport or industrial area and wish to improve your home's value at the same time.

Sash Window Bars

Classic sash windows have an astragal design, which means slim bars run across the glass, appearing like the panel is several much smaller pieces of glazing.

Modern homes with sash windows also look great with mid-rail bars as an updated design choice, but both are possibilities.

Astragal varies from Georgian sash window bars because the bars sit outside of the glazing and look like a continuous solid surface.

Georgian sash window bars are made slightly differently and don't have the same aesthetic.

Experienced window fitters can also show you a few other options, such as Victorian style sash window designs, all depending on the look you're aiming for and the age of your home.

Sash Window Frame Colours

One of the big appeals of UPVC is that you can order frames in pretty much any colour or design you wish - the UPVC is dyed during manufacture, so it's not a surface paint that will peel or crack.

White UPVC is the standard and the cheapest, but a coloured frame can add 30% to your budget (depending on the colour you choose).

Specialist finishes, such as a hardwood timber-effect or a chalk matte finish, can be 40% more costly but look stunning and will remain in excellent condition for just as long.

However, the appearance of the timber effect can be extremely convincing and be impossible to distinguish from real wood while being much more affordable, more durable, and a low-maintenance window frame.

Opening Options for New UPVC Sash Windows

The classic sash has a fixed upper pane and a moving lower pane - you slide the panel upwards to open it and downwards to close, with the frame running along a rope.

If you opt to replace an old sash, you have multiple options. Both panels can be fixed, one or the other can be moved, or both panels can slide vertically along the frame.

A further option for apartments, upper floors, or homes with young children is to fit a set of Rola locks.

These allow the window to be opened for ventilation but prevent the panel from being opened all the way and potentially presenting a safety risk.

Bespoke Sash Windows

Some properties don't have standard window sizes and may require specialist commissions to build bespoke windows to fit the exact style and size of each opening.

Optional extras such as timber architraves and custom finishes are also more expensive and can add £500 or thereabouts to the price for each window.

Experienced craftspeople will be able to design a UPVC sash window frame that exactly replicates the style of your current windows, which can be a deciding factor if you need planning permission to upgrade the glazing on a listed property.

How to Reduce Your UPVC Sash Windows Cost

Many window fitters will offer a finance option, whereby you spread the cost of your windows over several months but usually need to pay a nominal interest charge in return.

Sash windows can be fairly pricey, but UPVC is considerably cheaper than timber - it'll also boost your energy efficiency rating and require little to no maintenance. Hence, it tends to be more cost-effective as a long-term investment.

If you prefer a timber window, you can opt for Accoya frames, which are made from treated, high-quality timber that comes with a guarantee of up to 50 years.

You'll still need to keep up with the maintenance but should have far fewer problems than with a less durable softwood.

Homeowners with single-glazing may also be eligible for government window grants to help with the cost of upgrading their windows, along with other efficiency measures to make homes warmer and more affordable to heat.

Note that some finance offers can carry hefty interest charges, so it's important to obtain at least three quotations and carefully review the fees and repayment total before going down this route.

Benefits of Choosing UPVC Sash Windows for Your Home

There are lots of advantages to replacing tired sash windows with a new UPVC unit:

  • Improved insulation: UPVC is a high-performance insulating material, so it reduces heat loss, making it faster and less expensive to heat your home. It can also help minimise outside noise from reaching you when you're indoors.
  • Low maintenance: these windows need very little upkeep, aside from cleaning with a wet cloth and a mild detergent now and then.
  • Environmentally friendly: the UPVC used in the frame is recyclable, so in 20 or 30 years, if you decide to swap your windows, you won't be leaving a huge carbon footprint behind. The reductions in energy usage add to the eco-friendly performance points!
  • Longevity: new frames tend to last around 20-30 years, and most fitters offer 20+ year warranties for the glazing and UPVC. The windows are resistant to even extreme weather, chemicals and fire and don't lose their finish or colour in the sunlight.

Aside from these benefits, UPVC is a popular option because it is the most inexpensive type of window frame to buy and is very versatile, with countless finishes and colours to match the appearance of your home.

The pitfalls are few and far between, but some people don't like the look of modern sash windows, and a white UPVC can look out of place on an elegant period home, so a wood effect is normally the best solution.

UPVC is often considered preferable to timber because it lasts considerably longer.

The sliding mechanism in a sash window means that some parts of the frame are exposed to greater wear and tear than a standard casement window, so timber will begin to erode, with the potential for warping or rot if you experience a lot of dampness.

Loose sash windows are a security issue and cause draughts and heat loss, so it's best to get the highest quality sash window frame possible.

Modern UPVC sashes are fitted with spring tension mechanisms instead of the traditional rope with a counterweight, so they won't need any maintenance to remain in good order.

Older sash windows are susceptible to lax counterweights or the rope wearing through and breaking, hence the higher costs to restore old sash windows and replace all of these components.

Energy Cost Savings With a UPVC Sash Window

We noted earlier that The Energy Savings Trust indicates an average saving of £115 a year when replacing single-glazed sash windows - with recent price rises, that saving is likely many times higher.

The table below gives an estimate of how much you could save per year.

Property energy rating Flat Bungalow Terraced house Semi-detached house Detached house
A £40 - £60 £55 - £75 £65 - £90 £85 - £110 £120 - £160
B £40 - £55 £50 - £70 £60 - £80 £75 - £100 £110 - £145
C £40 - £50 £50 - £65 £60 - £75 £75 - £95 £110 - £135

In early 2022, energy prices are increasing by over 50%, so the cost savings each year could climb as high as £240.

Checkout the video below which talks through some of the different features of uPVC sash windows:

Frequently Asked Questions - UPVC Sash Windows Cost

Below we've answered some of the commonly asked questions about the average UPVC sash windows cost and what's involved in the installation process.

Do I Need Planning Permission to Install New UPVC Sash Windows?

Normally, most properties don't need planning permission to replace an old sash window with a new frame - although you may need approval from the local planning office if you live in a listed house or a conversation area.

The regulations vary between regions, so an experienced local window fitter will usually be able to help you navigate the planning rules and work out what permissions you need.

Period homes with timber sash windows sometimes need approval to substitute the frame with a UPVC replacement, although that depends on the nature of your home and the local planning rules.

Most local authorities will approve a sash window replacement if you're using a wood grain effect unit, which has a similar appearance while making the home more energy-efficient.

Can I Still Get New Sash Windows if I Live in a Listed Building?

The planning permission regulations for listed buildings mean that you will need approval to install any new windows or make any changes to the exterior of the building.

If your local authority doesn't grant approval for any reason, you can also consider alternatives, such as:

  • Replacing the old frames with a treated timber sash - or having the current windows refurbished by a sash window specialist.
  • Adding draught-proofing with an airtight seal fitted around the frames.
  • Installing secondary glazing - the window fitter adds an extra glass panel to the unit without removing the glazing as an added layer of insulation.

What Qualifications Should I Look for in a UPVC Sash Window Fitter?

Professional window fitters will be registered with and accredited by one of three bodies in the UK:

  • The governmental Competent Person's Scheme (CPS).
  • FENSA - the Fenestration Self Assessment Scheme.
  • CERTASS - this is part of the Competent Person's Scheme.

It's well worth checking your contractor's qualifications and experience because their work needs to comply with building regulations to be up to current standards - you'll get a certificate on completion that you will need if you ever come to sell your home.

These regulatory bodies are also important if something goes wrong or your windows start to fail after a few years. You will be covered by a formal complaints procedure, ombudsman investigations and have the option of making a compensation claim to cover the cost of repairs.

Another great thing to look out for is a local window fitter with knowledge about sash windows for your particular property type.

If you can read customer testimonials, see project galleries to check that the finished look is in line with what you're looking for, or even visit nearby properties with new UPVC sash windows, you'll know you are in good hands.

Can I Check the Energy Efficiency Performance of My UPVC Sash Windows?

There are two different metrics used to quantify energy efficiency - the Window Energy Rating and U-value.

The former measures the total energy efficiency of the window, which evaluates how much heat passes through the glass, how much heat it loses and the volume of warm air that escapes through tiny gaps in the frames.

A++ is the most efficient rating awarded, and G is the least - new double-glazing must be at least C-rated to comply with installation standards.

U-values are slightly different and measure how easily heat can pass through the frame and glass.

A low U-value means that the window is good at retaining heat.

New double-glazed UPVC sash windows have a U rating of around 1.2, whereas a single-glazed window will be rated at about 5.1.

Is it Worth Getting Triple-Glazed Sash Windows?

Double-glazing is the standard in the UK, and nearly every new window will be double-glazed to meet those building standards we've talked about.

The glazing contains two sheets of glass, with inert gas trapped in the layer in between, which keeps heat in, noise out and acts as an increased security measure since a double-glazed window is much harder to smash.

Triple-glazing is an upgrade and uses three rather than two panels.

Costs are higher, but triple-glazing can be advisable if you want the best possible energy efficiency, live close to a particularly noisy environment, and require additional protection from outside noise.

How Long Does the Installation Take for a New UPVC Sash Window?

If you purchase a UPVC sash window unit directly and need to pay only for the installation, the average charge will be from £300 to £500 per window.

There are cost efficiencies available if you install multiple windows at once.

One of the direct reasons installation ends up being more costly than expected, or takes longer, is because the fitter finds that additional work is required when removing your old windows.

For example, rotted timbers, damaged brickwork, an old lintel that requires replacement or crumbly plaster will add to the budget.

As an estimate, most sash window installations take from two hours and sometimes over a day if you have multiple windows installed, and there is a fair amount of work required.

What Styles of UPVC Sash Window Can I Choose From?

Sash windows are available as pre-designed units with classic lead weights and nylon chords - this is more durable than traditional rope.

The modern alternative is a pre-tensioned window with balanced springs that look like a sash. It is a more practical option since it has fewer moving parts.

Box sash windows can be a great choice, where the window has the weights, pulleys and chords to counterbalance the two sashes but is housed inside a box extending out from the frame on the inside and outside.

Spring balanced sashes are another option used in new builds with spring loaded mechanisms.

If you're unsure which style of sash to go for, it's best to ask a window fitter to show you the various options, or visit your home to recommend the right type of window.