Two neighbours, two similar houses, two quotes that look nothing alike. It is almost never arbitrary. A quote does not price "windows": it prices time, equipment, travel and risk. Here are the seven variables that explain nearly all the differences.
1. Surface area, but above all the layout
For the same area, one large pane cleans far faster than a series of small glazing-bar panes. The squeegee runs continuously across a large surface; on small panes each stroke starts again, every edge must be wiped, every corner reworked. Divided glazing can take two to three times longer than a solid pane of the same area.
For reference: the Belgian platform Bobex cites an average pace of about 75 m² per hour (page consulted on 30 July 2026). That is an average for ordinary, accessible surfaces — not for a compartmented roof light.
2. Which faces
Outside only, inside only, or both: the most underestimated variable.
The outside is worked continuously, with no interior constraint. The inside means entering, protecting floors and furniture, moving what is in the way, dealing with curtains, blinds, cluttered sills, pets, children and timing. The same window costs more to treat from inside than from outside, at equal area.
3. Height and access method
This is where the gaps become spectacular.
- Reachable from the ground with a pole or ordinary equipment: the cost is essentially time.
- Stable ladder on flat ground: time + caution + limited reach.
- Powered access platform: hire, transport, positioning, sometimes a municipal parking permit.
- Scaffolding or rope access: another trade, another budget, another schedule.
Two identical windows, one on the ground floor and one on the fourth floor with no balcony, have no reason to cost the same.
4. Level of soiling
A regularly maintained window cleans in one pass. A window left for several years often needs a pre-wash, a two-stage job, sometimes a local treatment of the deposits.
Beware the common misunderstanding: "very dirty" and "baked-on" are not the same. Dust, pollution, rain marks and organic residue come off. Baked-on limescale, paint, cement and cured silicone need a different treatment, with a result that is not guaranteed. See the guides on limescale and on post-construction cleaning.
5. Requested finish
Glazing, frame, casing and sill are four distinct elements. A quote that only says "window cleaning" generally covers the glass alone. Adding frames and sills adds time, product and equipment — it is legitimate that this shows in the price, provided it is written down beforehand.
6. Frequency
A single visit carries the travel, set-up and clearing away on its own. Planned maintenance spreads those costs across the year and, above all, reduces the workload at each visit since the glass never starts from zero.
7. Site logistics
This category is invisible in a photo and yet decisive:
- Parking available or not near the building
- Badge, code, key, lift, imposed access hours
- The need to work outside opening hours
- A manager or caretaker who must be present
- Road or pavement constraints on a shopping street
- A water point and power socket available or not
What this changes in your request
The more useful information you give upfront, the firmer the quote. What really makes the difference:
- The approximate number of windows and any large glazed surfaces
- The faces you want
- The highest floor concerned, and how it is reached
- A wide photo of each façade concerned, not just a close-up
- Any unusual marks, flagged explicitly
- Your timing and parking constraints
The point to watch in any quote
A quote with no limits is a quote to reread. Every service has limits: they are normal, and writing them down is the only way to avoid disagreement afterwards. With us, the quote systematically distinguishes the faces, the frames and sills, the access, and the marks for which no result is promised.
FAQ
Is a photo-based quote reliable? Yes, when the surfaces, access and condition are visible. Otherwise a site visit is better than an approximate figure corrected later.
Why am I asked for my postcode before anything else? Because travel is part of the cost, and because it is better to tell you straight away if the area is not served.
Can the quote change on the day of the visit? Only if reality differs clearly from what was described: different access, far heavier soiling, a larger surface. In that case we talk about it before starting, not after.