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Your window installation day, step by step

Fitting day is the part most people wonder about. Will there be mess? How long will the house be open to the weather? Here is how a typical window installation day unfolds, from the first knock to the final clean-up.

Before the fitters arrive

Your installer will confirm an arrival window, usually first thing in the morning. A crew of two is standard for a domestic job, sometimes more for a whole house. They should introduce themselves, run through the plan for the day and lay down dust sheets and floor protection before any tools come out. If you have followed our checklist for preparing your home, this part is quick and the team can get straight to work.

Removing the old windows

Fitters work one opening at a time so your home is never left wide open. The old sash or frame is removed carefully — modern crews rarely need to smash anything out — and the opening is cleaned up ready for the new unit. Old timber, glass and uPVC are set aside for responsible disposal and recycling rather than dumped in your garden.

Fitting the new units

Each new window is offered up, levelled and packed so it sits square in the opening. It is then fixed, sealed and made weathertight. The fitters check that every sash opens and closes smoothly, that locks engage and that trickle vents are clear. Around the frame they make good — filling gaps, replacing beading and finishing internal and external trims neatly. A good crew treats the finish around the window as part of the job, not an afterthought.

Sealing, testing and clean-up

Once the units are in, the team seals the perimeter inside and out, then wipes down the glass and frames. Before they leave they should walk you round every window, show you how the locks, restrictors and vents work, and hand over any keys. Offcuts, old frames and packaging go with them. A tidy handover is one of the things customers mention most often in our reviews.

How much disruption should you expect?

Less than you might fear. Because work moves opening by opening, rooms are only briefly exposed, and most homes stay warm and secure throughout. Expect some noise and a little dust, and keep pets and small children away from the work area. If you want a sense of the whole day's length, see our guide to how long window installation takes. New windows also quietly deal with a lot of the everyday problems new windows solve, so the disruption pays off fast.

Signing off the work

At the end, you confirm you are happy and the installer notes anything to return for. This is when you should receive details of your guarantee and be told when your certificate will follow — covered in our guide to FENSA certificates and building regs. If anything is not quite right, our aftercare and snagging guide explains how to raise it. Choosing a fitter you have taken care in vetting your installer first is the surest way to a smooth sign-off.

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