Draughty windows fixed by Faron Home Improvements

How much does double glazing cost? A standard uPVC casement window costs roughly £350 to £550, fitted. However, replacing every window in a typical 3-bed semi-detached house costs around £3,750 to £7,000. Aluminium and timber cost more, and sash, bay and non-standard windows push the price up further.

First, note that the figures below are 2026 UK averages including VAT. Your own quote will also depend on window size, style, access and your area.

Grey double glazed bay window, an example of how much double glazing can cost

Double glazing cost per window (supply and fit)

Overall, prices rise as you move from simple casements to sash and bay windows. Likewise, aluminium and timber cost more than uPVC.

Window type uPVC Aluminium Timber
Casement £350–£550 £600–£850 £750–£1,100
Tilt-and-turn £450–£700 £700–£950 n/a
Sash £700–£1,100 £1,100–£1,400 n/a
Bay (3 panels) £1,200–£2,500 £2,000–£3,000 n/a

However, these prices apply to a standard casement of about 1200mm x 1200mm. Source: ExpertSure.

Cost to double glaze a whole house

Overall, the total depends mostly on how many windows you have and which frame you choose.

Property Windows uPVC Aluminium Timber
3-bed semi-detached 8–10 £3,750–£7,000 £4,700–£5,600 £7,500–£12,000
4-bed detached 10–15 £5,500–£7,000 £7,000–£9,000 n/a

Sources: ExpertSure and MyBuilder (updated August 2026). Overall, a flat or small terrace with 4 to 8 windows usually falls between roughly £1,300 and £4,000.

What changes your quote?

Several factors move your quote up or down. For example, you can save money by choosing standard sizes.

  • Frame material. For instance, uPVC costs the least, aluminium costs more, and timber costs the most.
  • Window style. Casements cost the least, while tilt-and-turn, sash and bay windows cost progressively more.
  • Size and shape, because large or made-to-measure windows cost more than standard sizes.
  • Glass specification. Argon gas adds about £30 to £40 per window, and an A+ or A++ energy rating adds about £40 to £80.
  • Access, since upper-floor work can need scaffolding at £300 to £800 per elevation.
  • Finally, conservation areas and listed buildings can need specialist frames and installers.
  • Extras such as skip hire (£200 to £350), new sills (£30 to £60 each) and making good (£50 to £100 per window).

Is it worth the money?

For most homes, yes. First, new windows cut draughts and heat loss, reduce outside noise and can improve your home’s energy performance rating. Also, a well-made uPVC window typically lasts 20 to 25 years, so the cost per year stays modest. Read how long uPVC windows last for the full breakdown.

Get an accurate price for your home

Every home is different, so the quickest way to a real price is a measured quote. Faron Home Improvements is FENSA-registered, and we fit double glazing across Sussex, Surrey and Kent. Still asking how much does double glazing cost for your home? Call us on 01342 643075 or request a free quote, and we will give you a clear, itemised price with no pressure.

Double glazing cost FAQs

How much does double glazing cost for a 3-bed semi?

Overall, it typically costs £3,750 to £7,000 for uPVC windows, depending on the number and style of windows. Aluminium costs around £4,700 to £5,600, while timber costs £7,500 to £12,000.

How much does one double glazed window cost?

First, a standard uPVC casement costs about £350 to £550 fitted. However, sash and bay windows cost much more, from around £700 up to £2,500.

Is it cheaper to replace just the glass?

Yes. For example, replacing only a failed sealed unit costs about £55 to £145 per unit. However, this only makes sense if the frame is still in good condition. See our guide to misted double glazing.

Does double glazing need a FENSA certificate?

Yes. Replacement windows and doors must comply with Building Regulations, so a FENSA-registered installer certifies the work and gives you a certificate.

How long does installation take?

Overall, a typical house usually takes one to two days, depending on the number of windows. Also, made-to-measure windows take a few weeks to arrive first.

Does double glazing add value to a home?

Also, it can improve saleability and energy performance. However, the exact effect on value depends on the property and the local market.

Is uPVC or aluminium better for double glazing?

uPVC costs less and needs little upkeep, so most homeowners choose it. However, aluminium costs more but has slimmer frames, and it can last longer. Therefore, the right choice depends on your budget and style.

Can I get finance for double glazing?

Also, some installers offer payment plans. Therefore, ask for a quote and check the terms first if you want to spread the cost.

Do I need planning permission for new windows?

Usually not for a like-for-like replacement. However, listed buildings and some conservation areas have extra rules, so check with your local council first.

Will new windows cut my energy bills?

Yes, often. Modern double glazing keeps more heat inside, so your heating works less hard. As a result, many homeowners notice warmer rooms and lower bills.

What guarantee should I expect?

In addition, most installers give a guarantee on the windows and the fitting. So ask for the details in writing before you agree to the work.

Related guides and local services

Read more about windows and glazing from Faron Home Improvements:

Last updated: October 2026. Prices are UK averages including VAT and are a guide only.