What to tell an installer for an accurate window quote

The single biggest reason two quotes for the “same” windows come back hundreds of pounds apart is that each installer was working from different information. An accurate window quote starts with a clear brief. The more precisely you describe your home, the fewer surprises appear on the final invoice — and the easier it is to compare one installer against another. Here is what to have ready before anyone visits.

How many windows, and where

Start with a simple count: how many windows and doors you want replaced, and which rooms they are in. Note any that are awkward — a landing window over a stairwell, a bay at the front, or anything above the ground floor that will need access equipment. You do not need millimetre-perfect measurements at this stage; a proper home survey covers that. A rough width and height per opening is plenty to get comparable ballpark figures.

Style, material and glazing

Tell each installer the look you are after. Are you keeping the existing style, or switching from, say, sash to casement? Do you want uPVC, aluminium or timber frames, and a particular colour or finish such as anthracite grey or a woodgrain effect? Mention the glazing too — standard double glazing, a low-emissivity coating, acoustic glass for a busy road, or triple glazing. If you are unsure, our guide to matching glazing to your home walks through the options.

Access, timing and extras

Practical details change the price. Flag parking restrictions, a shared drive, or a conservatory that limits access to the rear. Say whether you need the work finished by a particular date, and mention anything that might need making good afterwards, such as internal plastering or external rendering around the reveals. If your home is listed or in a conservation area, tell installers early — it affects both the specification and any permissions required. Understanding how a full specification comes together is easier when you read about how a professional-grade window specification is put together.

Give everyone the same brief

The golden rule is consistency. Whatever you tell one installer, tell them all. If you decide midway to add a back door or upgrade the glass, circle back to the earlier quotes so they can update their figures. When every installer prices the same job to the same standard, the differences that remain — product quality, guarantee length, lead time — are the ones that should decide it.