How long does a full window replacement take in 2026?
If you are planning to replace all the windows in your home, the total time from placing your order to the final day of fitting is typically 4 to 10 weeks. The on-site work itself is much shorter.
The full replacement of a typical UK home’s windows takes 2 to 4 working days from scaffold to finish. For a three-bedroom semi-detached house, the average installation time on-site is 2–3 days, with a further 4–8 weeks from survey to fitting date (Glass and Glazing Federation (GGF) Code of Practice, 2026).
The pre-installation phase takes 4 to 8 weeks for survey, manufacturing, and scheduling
The first step after you choose your windows and place the order is the survey. A surveyor visits your home to measure every window opening and check for any structural issues that might affect the installation. This appointment usually happens 1–2 weeks after you place the order (FENSA registered installer directory, 2026).
Once the survey is complete, the windows are manufactured to your exact measurements. For standard uPVC windows, the lead time is 3–5 weeks. Timber or aluminium frames take longer, typically 6–8 weeks (GGF member guidance, 2026). After the windows are ready, the installation team schedules the fitting date. This scheduling step adds another 1–2 weeks.
Day 0 Scaffolding and site preparation adds 1 to 2 days before fitting
If any of your windows are on the first floor or higher, scaffolding needs to be erected before the installation team arrives. Scaffolding erection takes 4–6 hours and costs between £400 and £800 (Scaffolding Association UK, 2026).
You also need to prepare the inside of your home. Move furniture away from the windows, and remove all curtains, blinds, and nets. Keep your driveway or parking space clear for the delivery vehicle and for a skip if you have ordered one for old frame disposal (CITB site preparation guidance, 2026).
Day 1 Removal of old frames and fitting of new ones takes 6 to 10 hours
This is the main day of work. The installation team removes each old window frame and fits the new one. Each window removal and installation takes between 45 and 90 minutes, depending on the condition of the existing frame and how easy it is to access (FENSA installation standards, 2026).
Old frames are disposed of immediately. If you have ordered a skip, a 4-yard skip costs between £150 and £250 (WRAP waste guidance for construction, 2026). The new frames are fitted into the openings, levelled, and temporarily secured with packers and fixings.
Day 2 Glazing insertion, sealing, and external finishing completes the main work
On the second day, the double or triple glazing units are inserted into the frames and secured with beads. External silicone sealant is applied around all frame edges. This sealant needs 24 hours to cure before any painting or rendering work can be done (GGF technical bulletin on sealant curing, 2026).
Trickle vents are fitted and tested. Handles, locks, and hinges are adjusted to make sure they operate correctly. This work follows British Standard BS 8213-4 for security of windows and doors (British Standard BS 8213-4, 2026).
Quick numbers Typical costs and time savings from window replacement
| Item | Typical figure | Notes |
|---|---|---|
| Average installation time (3-bed semi) | 2–3 days | Day 1 removal and fitting; Day 2 glazing and sealing |
| Pre-installation lead time | 4–8 weeks | Survey to fitting date |
| Scaffolding cost | £400–£800 | For first-floor access |
| Skip hire (4-yard skip) | £150–£250 | For old frame disposal |
| Average energy saving per year | £195–£420 | Replacing single glazing with A-rated double glazing |
| Payback period | 8–15 years | Based on energy savings alone |
Source: Energy Saving Trust (EST) window replacement report 2026; EST typical savings calculator, 2026; GGF cost survey, 2026
The payback calculation for window replacement in 2026
Replacing single glazing with A-rated double glazing saves between £195 and £420 per year on energy bills for a typical semi-detached house (EST “Window replacement” guidance 2026). The total replacement cost for a three-bed semi is £3,500 to £7,500, depending on frame material, number of windows, and glazing specification (DESNZ “Energy consumption in the UK” data release 2026).
The simple payback period from energy savings alone is 8–15 years. When you add the house value uplift that new windows provide, the effective payback period reduces to 5–10 years (Nationwide Building Society house price index, 2026).
For more detail on how much you might save with different glazing types, see energy savings from double glazing vs triple glazing.
How to verify your installer is certified and insured before fitting begins
All window installers in England and Wales must be registered with a Competent Person Scheme such as FENSA or CERTASS to comply with Building Regulations. You should check the installer’s FENSA registration number on the FENSA website before work starts (GOV.UK “Building Regulations: Competent Person Schemes”, 2026).
Verify that the installer has public liability insurance with a minimum of £2 million cover. Request a written contract that details the installation timeline, materials, warranty, and payment schedule. Typical warranties are 10 years for uPVC frames and 5 years for glazing units (GGF consumer code, 2026).
To understand what happens if your installation is delayed, read window installation delays and your consumer rights.
Frequently Asked Questions
A full window replacement takes 4 to 10 weeks from order to completion. The on-site fitting itself is just 2 to 4 days, with the rest being survey, manufacturing, and scheduling (Glass and Glazing Federation Code of Practice, 2026).
Fitting windows in a 3-bed semi-detached house takes 2 to 3 days on-site. This includes removing old frames and fitting new ones, according to FENSA registered installer data for 2026.
Windows are typically fitted 4 to 8 weeks after the survey. This includes 3-5 weeks for manufacturing (uPVC) and 1-2 weeks for scheduling the fitting date (GGF member guidance, 2026).
Yes, scaffolding is needed for any first-floor windows or higher. Erection takes 4-6 hours and costs £400 to £800, as reported by the Scaffolding Association UK in 2026.
Move furniture away from windows, remove curtains and blinds, and clear your driveway for delivery vehicles and a skip. This follows CITB site preparation guidance for 2026.
