Fitting a standard set of replacement windows and doors typically takes one to three days for a typical three-bedroom semi-detached house, according to the FENSA (2026) industry guidance.
The exact time depends on the number of openings, the type of frame material, and whether any structural work is needed. A straightforward swap of like-for-like uPVC windows on a ground floor is much faster than fitting composite doors or aluminium bi-folds, which may require additional preparation and adjustments.
Number of openings is the main factor
A professional team of two fitters will normally complete a standard house with eight to ten windows and one door in one to two days. The TrustMark (2026) accredited installers advise that each window takes around 45 minutes to an hour to remove and replace, depending on access and existing frame condition. A composite front door typically takes two to three hours because the frame and threshold need precise alignment. Adding a second door, such as a back door or patio door, can add half a day to the schedule.
Frame type and structure affect installation time
uPVC windows are the fastest to fit because they are pre-assembled and lightweight. Aluminium frames are heavier and require more careful handling, adding roughly 20% to the fitting time per opening, according to BRE (2026) installation guidance. Timber windows often need on-site painting or staining, which can extend the job by a full day. If the existing frames are rotten or need brickwork repairs, the installer must allow extra time for making good, which can add another half day per affected opening.
Bi-fold and sliding doors take longer
Bi-fold doors are the most time-intensive glazing installation. A set of four to five panels can take a full day to fit because the track must be perfectly level and the folding mechanism aligned. MCS (2026) certified installers report that larger configurations, such as six to eight panels, may require two days. Sliding patio doors are quicker, usually taking three to four hours, but still longer than a standard hinged door because of the heavy glass panels and roller system. Always ask your installer for a written timeline before work starts, as site conditions vary.
A worked example
Glazing is standard-rated for VAT at 20%. The zero rate for energy-saving materials covers insulation, heat pumps and solar panels; HMRC names secondary and double glazing as excluded (VAT Notice 708/6). A team of two fitters completes this job in two full days, with each window taking around 50 minutes and the door requiring three hours for frame alignment. The Energy Saving Trust estimates that replacing single-glazed windows with A-rated double glazing saves a semi-detached home approximately £195 per year on heating bills. Over 25 years, the total saving reaches £4,875, meaning the payback period sits at roughly 17 years when factoring in the reduced upfront cost. If the existing frames are in poor condition, expect an extra half-day for structural preparation, which pushes the total to two and a half days.
| Item | Figure |
|---|---|
| Upfront cost after grants | £8,500 |
| Yearly savings | £195 |
| Payback period | 17 years |
| 25-year lifetime savings | £4,875 |
What homeowners often get wrong
The most common mistake is assuming all windows take the same time to fit, which leads to unrealistic scheduling and missed work deadlines. Here are three frequent errors homeowners make when planning their installation timeline.
- Thinking aluminium is as fast as uPVC Aluminium frames are heavier and require more precise handling, adding roughly 20% more fitting time per opening. A bay window in aluminium can take two hours instead of 75 minutes for uPVC, which adds a full half-day to a nine-window job.
- Forgetting about scaffold access for upper floors Ground-floor swaps are straightforward, but first-floor windows on a three-storey townhouse need scaffolding, which adds a full day for setup and removal. Without planning this, homeowners face a two-day delay and an unexpected £500 to £800 scaffold hire cost.
- Ignoring the door threshold preparation A composite front door requires precise frame and threshold alignment that takes two to three hours, not the 45 minutes many expect. Rushing this step voids the 10-year insurance-backed guarantee from the installer, leaving you unprotected against draughts and water ingress.
Quick reference
- A standard three-bedroom semi-detached house with nine windows and one door takes one to two days for a two-person team to complete.
- Each uPVC window takes 45 minutes to an hour to remove and replace, while aluminium adds 20% more time per opening.
- ECO4 funding covers window and door replacements for eligible low-income households, but only if the existing glazing is single-pane or broken.
- Replacing single glazing with A-rated double glazing saves a typical semi-detached home £195 per year, according to the Energy Saving Trust.
- Composite front doors require two to three hours of fitting time because the frame and threshold need precise alignment to avoid voiding the guarantee.
Frequently Asked Questions
A composite front door typically takes two to three hours to fit. TrustMark accredited installers advise that the frame and threshold require precise alignment, adding to the time.
Yes, aluminium windows take roughly 20% longer per opening than uPVC. BRE guidance confirms this is due to the heavier frames requiring more careful handling.
A professional team of two fitters can usually install eight to ten windows in one day. This estimate assumes standard uPVC replacements with good access and sound existing frames.
