How Do You Calculate the Price of a Window Clean?

Two quotes for the same windows can differ threefold. That isn't arbitrary: the price of a window clean almost never depends on surface area alone. We price jobs across Paris and Île-de-France year-round, and the biggest driver of variation isn't the square metre — it's access.

This article gives you our full method, with the ranges we actually charge, the coefficients we apply, and a fully itemised worked example. The aim is simple: to let you estimate your budget before you even request a quote, and above all to compare two proposals that look alike but don't cover the same thing.

The three billing models and when each applies

Contrary to what's often written, a window cleaning professional doesn't automatically bill per m². In practice three logics coexist, each answering a specific situation.

1. Billing per m² of glazing

This is the clearest model and the easiest to compare. It works well on uniform, repetitive surfaces: an office building with identical frames, a continuous façade, a glazed floor plate. One caveat: we mean m² of glazing, not m² of floor space. A 500 m² floor can carry anywhere from 80 to 250 m² of glazing depending on the architecture — and the price follows.

2. A flat fee per visit

As soon as the glazing is small, uneven or fragmented, the square metre stops reflecting real time. A single 6 m² shopfront pane takes minutes; six small windows with glazing bars totalling the same area take three times as long. That's why we apply a flat fee in these situations:

• Small shops and shopfronts: typically €25 to €80 depending on area and configuration.
• Medical and paramedical practices: €40 to €120, with monthly frequency the norm.
• Offices under 300 m²: a bespoke flat fee, because per-m² pricing becomes misleading at that scale.

3. Time-based pricing, adjusted for technical constraints

On large office buildings we start from estimated working time, then add technical constraints: access equipment, number of operatives, imposed time slots, coordination with building security. It's the fairest method at volume, and it explains why two buildings of identical size don't produce the same quote.

Real price ranges in Île-de-France

These are the price levels we observe and charge in the Paris region. They're market ranges, not a fixed scale: use them to place a quote, not to replace one.

To place those figures on a common case: a 500 m² office floor carrying around 180 m² of glazing usually falls between €350 and €700 per visit, depending on configuration, access and the starting condition of the glass.

The coefficients that actually move the price

This is where most of the gap between two quotes is decided. The base rate is only a starting point; the coefficients build the final price.

Access: the number one factor, far ahead of surface area

If you remember one thing, make it this. Ground floor is charged at base rate. A first floor reachable with a carbon pole adds 10–20%. As soon as a cherry picker is needed, the quote can easily double: it has to be hired, positioned, sometimes permitted for street occupancy, and operated by certified staff. And when rope access becomes necessary, you change price category entirely, because it's a different trade.

Starting condition: the first pass is never at maintenance rate

Neglected glazing needs restoration, not maintenance. Paris air pollution bonds to glass over time and no longer lifts with water alone. Expect 30–50% more on the first visit. In hospitality, airborne grease adds 20–40%. And after building works, cement or laitance splashes can double the job time, because each spot must be treated individually without scratching the glass.

Scope: what the quote actually covers

Cleaning inside and outside takes roughly double the time of a single face. That's arithmetic — and it's the number one lever used by abnormally low quotes: they only price the outside. Add frames, sills and sliding-door tracks, which are hand work rather than squeegee work. Glazed roofs are a category of their own: extremely time-consuming, they're almost always priced by time.

The five-step calculation method

Here's the exact sequence we follow to price a job. You can apply it yourself to get an estimate before calling us.

Step 1 — Measure glazing area, not floor area

Add up each pane: height × width, frame by frame. Count the area once, even if both faces are to be treated — the second face is handled later, either in the base rate or as a coefficient. List glazed roofs separately, as they follow a time-based logic.

Step 2 — Choose the base rate for the regime

Scheduled maintenance: €2–4 per m². One-off visit on standard glazing: €4–7 per m². Take the bottom of the range for simple, unobstructed glazing; the top for numerous frames, glazing bars or heavy framing. Below 300 m² of offices, stop the calculation here and move to a flat fee.

Step 3 — Apply the access coefficient

This is the decisive step. Ground floor: nothing. First floor by pole: +10–20%. Cherry picker: assume a doubling. Rope access: per-m² pricing no longer applies and a dedicated quote is required. Be honest with yourself here — this is the factor that blows up the gap between an estimate and a final quote.

Step 4 — Add condition and scope coefficients

First pass on neglected glazing: +30–50%. Kitchen grease: +20–40%. Post-construction: up to double. Then check that your estimate really includes both faces, frames, sills and tracks — if it doesn't, you aren't comparing the same service.

Step 5 — Deduct the frequency discount

A monthly maintenance contract generates a 20–40% discount versus a one-off visit. That isn't a commercial gesture: maintained glass cleans faster, the visit fits into a round, and the provider no longer has to price in the risk of degraded glazing. It's the only lever that lowers a quote without degrading the service.

A worked example, line by line

Take a case typical of what we see in Paris: a 500 m² office floor in the 9th arrondissement carrying around 180 m² of glazing, split between ground and first floor. Inside and outside. Untreated for fourteen months. The client's goal: move to quarterly maintenance.

So the client pays €700 excl. VAT the first time, then €520 excl. VAT per visit. If they opt for monthly rather than quarterly frequency, the frequency discount brings each visit down to roughly €350–420 excl. VAT — for glazing that stays clean permanently.

Checking a quote before you sign

A quote that's half the price of the others almost always hides something. Not necessarily bad faith — often simply a narrower scope. Here's what we see most often in the Paris market.

The six most common traps

• Only the outside face is included. This is trap number one, and it mechanically halves the price.
• Frames are excluded. Immaculate glass surrounded by dirty frames: the visual result disappoints, and you find out after the visit.
• Sills and sliding-door tracks aren't cleaned. These are precisely the areas you notice when you open the window.
• No restoration step is planned on heavily soiled glazing: the provider applies a maintenance rate to a situation that doesn't qualify.
• Layered subcontracting. You sign with one company, a second executes, a third supplies the operatives. When something goes wrong, nobody is accountable.
• Stopwatch scheduling with an obligation to finish regardless. That organisational model is what produces streaks, omissions and damage.

The pre-signature checklist

Six points to check every time, whoever the provider — including us:

1. How many faces are cleaned: outside only, or inside and outside?
2. Are the frames included in the quoted price?
3. Are sills and tracks on sliding doors covered?
4. Is a restoration step planned and priced for the first visit?
5. Is access equipment (pole, cherry picker, street permit) included or charged as an extra?
6. Is professional liability insurance current, with a certificate to prove it?