How to Plan a Full-House Window Replacement

Any installer quoting from a photo or a phone call is guessing. Insist on a full technical survey — measuring each opening, noting structural issues, identifying which windows are egress, checking cills, cavity trays and lintels. A proper survey takes 60–90 minutes. It's what a serious installer does.

Whole-house uPVC replacements typically run £5,000–£12,000 for a 3-bed semi, £8,000–£20,000 for a 4-bed detached. Aluminium and timber-alu are 40–80% higher. Add 10–15% contingency for unexpected work (structural issues at cill level, lintel repairs, redecoration). Get three quotes but weight the specification, not just the headline price.

Whole-house replacements typically take 2–5 days for a 3-bed, 4–8 days for a 4-bed. Windows come out and go back the same day — the house isn't left open overnight. Book a run of stable weather; storm week is not the week for it. Plan to be at home for the first morning to walk the installer through any quirks.

1) Style and material (uPVC, timber-alu, aluminium). 2) Colour and finish. 3) Glazing bar pattern (if any). 4) Handle style and colour. 5) Trickle vent colour. 6) Cill depth (75mm vs 150mm). 7) FENSA guarantee period. Making these decisions in this order avoids the common problem of changing your mind mid-manufacture.

On completion, walk every window with the installer. Check: even 3mm gap around every opener, smooth operation, correct handle and lock function, tight silicone bead inside and out, and correct trickle vent operation. Sign the completion note only when you're satisfied. FENSA certificate arrives 4–8 weeks later — keep it with the house paperwork.