Every YouTube tutorial teaches the [fan stroke](/glossary#fan-stroke) on the first day. That is the wrong day to learn it. Here is when to actually reach for it, and what to do until you can.
I have been cleaning windows in New York for twenty-two years. Before that I trained in Copenhagen for three. In all of that time, I have used the fan stroke for maybe a quarter of the windows I have done. The rest were straight pulls. And yet on YouTube, on every short-form social platform, on every "how to clean windows like a pro" video that crosses my feed, the fan stroke is the first technique anyone teaches. Frequently the only technique.
This is wrong, and the wrongness has consequences. Beginners who learn the fan stroke first develop a habit of unnecessary motion, fail to control their water, and produce streaks they do not understand the source of. Then they decide they are bad at this. They are not bad at this. They are doing the right move at the wrong time.
I want to walk through what the fan stroke actually is, why it exists, when to use it, and — most importantly — what to use instead until you have earned it.
The fan stroke is a continuous serpentine motion in which a squeegee never leaves the glass during a single pass. The cleaner starts in the upper left corner, pulls down, then arcs the squeegee's leading edge across to the right, then back, then across again — tracing an S-curve that covers the whole pane in one connected gesture. The trailing edge of the squeegee always remains in contact with already-cleaned glass, which is the entire point: the rubber never crosses dry-to-wet again. This is what allows a skilled fan-stroker to leave no edge marks anywhere on the pane.
The other major technique — the straight pull — is what it sounds like: the squeegee comes down vertically (or horizontally, depending on the school), stops at the bottom, lifts, dries against a scrim, and starts the next pull alongside the previous track. Each pull is independent. Tracks overlap by about half an inch. The trailing edge of each pull leaves a small line of water that is wiped clean with the detail cloth at the end.
Both techniques produce clean glass. They produce clean glass in different ways, with different failure modes, and — most importantly — with different difficulty curves.
The fan stroke was developed for a specific working condition: commercial storefronts with large, uninterrupted panes that need to be cleaned quickly and from a single position. A New York storefront window is often six feet by ten feet, on a sidewalk, with traffic. You do not have time to do four straight pulls and four detail wipes per window when the route is forty windows and the truck is double-parked.
In that context the fan stroke is faster — maybe 30% faster on a large pane — because the squeegee never leaves the glass and there is no per-pull lift, dry, and reposition. The skilled commercial cleaner can do a six-by-ten pane in one continuous gesture in about eight seconds, with one detail wipe at the perimeter and no other touch-up. That is what the technique is for.
The fan stroke is not faster on a residential double-hung window. It is slower. And it is much, much harder.
Two reasons, neither of them good. The first is that the fan stroke looks more impressive on video. A continuous fluid motion is more cinematic than a series of disciplined parallel pulls, and short-form video rewards what looks impressive. The second is that most YouTube window-cleaning content is made by route cleaners who cleaned commercially first and forgot what it is like to not know how to do this. They teach the move they use most. They do not teach the move that beginners should learn first.
If you are cleaning your own house, on residential double-hungs that are mostly two feet by three feet, the fan stroke is the wrong starting point. You are going to get worse results, develop bad habits, and quit because you cannot understand why your windows look streaky.
Learn the straight pull first. Specifically, learn the top-down variant, where you start in the upper-left corner, pull straight down to the bottom of the pane, lift, dry against a scrim tucked into your back pocket, reposition the squeegee to overlap the previous track by a quarter to half an inch, and pull again.
This sounds tedious. It is not. With practice, a residential double-hung becomes four or five pulls — about fifteen seconds of squeegee work, plus a detail wipe of the perimeter with a microfiber cloth. That is faster than a beginner's fan stroke, which on a small pane often involves three or four restarts and a frustrated re-mop because the cleaner could not control the trailing edge in the corner.
The straight pull is also dramatically easier to diagnose when something goes wrong. If you have a streak, the streak is in one of the pulls, and you can see exactly which one and why. If a fan stroke streaks, the streak could be from any of fourteen places along the serpentine path, and you do not know which until you have done it many times.
Mara wrote a full piece on the four-stage wash — apply, squeegee, detail, inspect — and that piece uses the straight pull throughout for exactly this reason. The four-stage method is the foundation. The fan stroke is a finishing move you graduate to.
You have earned it when:
You can do six straight-pull windows in a row without a streak. Not five. Six. The reason for the high bar is that the fan stroke punishes inconsistency. If you are still occasionally getting streaks on straight pulls, switching to the harder technique will produce more streaks, not fewer.
You can dry your rubber against a scrim without thinking about it. The fan stroke requires the rubber to remain at a precise water content throughout the gesture — wet enough to glide, dry enough not to leave a track. Beginners cannot feel this. Experienced cleaners can.
You can read your trailing edge in real time. This is the one that takes longest to learn. The fan stroke depends on knowing, at each moment, where the trailing corner of the squeegee is in relation to the not-yet-cleaned glass and the already-cleaned glass. If your trailing edge crosses onto dry glass, you leave a track. If it crosses onto wet glass at the wrong angle, you leave a track. The reading is mostly proprioceptive — you feel it more than you see it — and it takes about a season of full-time work to develop.
You are working on panes large enough to make it worth it. This is the simplest test. If your pane is smaller than four feet wide, the fan stroke saves you no time and adds error. Save it for the big ones.
In our Technique Library we have animations that show the difference between a fan stroke executed correctly and one executed by a beginner. Watch the trailing edge in both. You will see what I mean.
I do not teach apprentices any more — there is a generation of cleaners coming up under other people now — but I still consult on training problems. Here are three things I see beginners do with the fan stroke that I want to call out specifically.
Mistake one: starting in the wrong corner. Right-handers should start in the upper left. Left-handers should start in the upper right. The reason is that the squeegee leads with the dominant hand, and the trailing corner needs to be on the opposite side from the dominant hand to allow a clean pivot at the bottom of each S-curve. Starting in the wrong corner forces the cleaner to pivot through a contortion that almost always leaves a track.
Mistake two: too much water. The fan stroke depends on a precise amount of solution on the glass — enough to lubricate the rubber, not so much that water sheets off the trailing edge during the pivot. Beginners over-apply because they were taught to "saturate the glass," which is correct for the straight pull and wrong for the fan stroke. If you are fan-stroking, use about 60% of the solution you would for a straight pull on the same pane.
Mistake three: pivoting at the wrong rhythm. Each pivot at the bottom or top of an S-curve has to be a deliberate move with the squeegee at a specific angle to the glass — about thirty degrees at the moment of pivot, then back to the canonical fifteen-degree pulling angle as soon as the new direction begins. Beginners pivot at the same angle they pulled at, which creates a sharp diagonal track that no detail cloth can fix without re-soaping the corner. A skilled fan-stroker varies the squeegee angle continuously through the gesture. This is the part that takes seasons.
I have been told, more than once, that I am being a Copenhagen snob about this. The argument runs that the fan stroke is the more elegant technique, that working cleaners should aspire to it, and that teaching the straight pull as the default is to settle for less.
I think this is backwards. The straight pull is not less elegant. It is the same trade, executed at a different scale, with different failure modes. A sushi chef does not start their apprentices on omakase. They start them on rice. The straight pull is the rice. Master it and the fan stroke will come on its own, in the third or fourth season, when your wrist already knows what your eyes are about to ask of it.
If you cannot get a clean window with a straight pull, you will not get a clean window with a fan stroke. You will get a window with the same problems, plus three additional problems you do not yet have the vocabulary for. Save yourself the frustration. Learn the fundamentals first. The fan stroke is waiting for you on the other side.
Abby Giordano is part of the Giordano Inc. editorial team and covers the Northeast and New England editorial beat for Window Washing Guide. Editorial content is researched and reviewed in collaboration with the Giordano Inc. editorial team and informed by interviews with practicing window-washing operators in the region, plus published trade and apprenticeship technique references.