Quick answer: For most homes, clean exterior windows every 1–2 months and interior glass every 2–3 months, with a minimum full clean twice a year (spring and autumn). Clean more often if you live near a main road, the coast, under trees, or have pets and small children fond of glass doors. The honest reason most people fall short isn't laziness — it's that the chore costs a weekend. Make it cost minutes and the schedule keeps itself.
Be honest: when did you last clean your windows? Not "wiped a smudge" — actually cleaned them, all of them, both sides?
If the answer is "when the low winter sun publicly humiliated me," you're in the majority. Nobody has a window schedule. Windows get cleaned the way smoke alarms get new batteries — rarely, reactively, and right after an incident.
Here's what the schedule should be, what it quietly costs you to skip it, and the cheat that makes keeping up nearly effortless.
The recommended schedule (by situation)
| Your situation | Exterior | Interior |
|---|---|---|
| Standard suburban home | Every 1–2 months | Every 2–3 months |
| Near a main road or city centre | Monthly (traffic film builds fast) | Every 2 months |
| Coastal | Monthly (salt spray etches glass over time) | Every 2–3 months |
| Under trees / high pollen area | Monthly in spring & autumn | Every 2–3 months |
| Pets, kids, patio doors | As above | Every 2–4 weeks (you know why) |
| Absolute minimum, any home | Twice a year | Twice a year |
Why exteriors more often? Because outside dirt isn't passive. Bird droppings and tree sap are mildly acidic and etch into glass coatings if left through a hot spell; salt and hard-water minerals bond to the surface over months. Glass that's cleaned regularly cleans easily; glass cleaned yearly needs the double-pass treatment — it's the same reason window cleaners charge extra for first visits.
What dirty windows actually cost you (it's not about the neighbours)
- Light. Grime measurably cuts the daylight coming through — dirty glazing can block a meaningful chunk of it, which is why commercial buildings clean glass on strict rotations. You paid for those windows; film and traffic haze are a dimmer switch you never asked for.
- Mood and energy. Natural light exposure is one of the best-documented inputs to sleep quality and daytime alertness. More daylight through your biggest light sources is the cheapest wellbeing upgrade in the house.
- Heating, slightly. Winter solar gain through south-facing glass is free warmth; grime skims some of it off.
- The glass itself. Etching from droppings, sap and mineral deposits is cumulative and eventually permanent. Cleaning is also maintenance.
Why nobody keeps the schedule (and the redesign)
Let's do the maths on the "proper" schedule for an average house: 10–20 panes, inside and out, at 2–4 hours per full session, monthly-ish. That's 30–50 hours a year of bucket work. Of course nobody does it. The schedule isn't unrealistic — the cost per clean is.
So change the cost, not the schedule. This is exactly what happened with floors: nobody vacuums more than they did in 1995 because they became more disciplined — robot vacuums made frequency free.
Same move, vertical surface: a robot window cleaner like the CleanBot R1 turns "clean the patio doors" from a 20-minute chore into place robot, press button, unload dishwasher while it works. It grips the glass by suction, mists and wipes in overlapping passes, and does pane after pane to the same standard (how it works — and no, it doesn't streak, consistency is the whole trick).
When a full-house glass session drops to ~30 minutes of your time — most of it spent doing something else — the monthly schedule stops being aspirational and starts being what just happens. That's the entire secret: people don't need more discipline, they need cheaper cleans.
Your minimum viable window routine
- Monthly: robot runs on high-traffic glass — patio doors, kitchen window, front-facing panes
- Quarterly: full house, inside and out (robot does reachable glass; pole or pro for high fixed exteriors)
- Twice a year: frames, sills, tracks and gutters while the glass is being done
- After storms/pollen dumps: spot-run the worst-hit panes — it's one button now
FAQ
How often should windows be cleaned inside and outside?
Exterior: every 1–2 months (monthly near roads, coast or trees). Interior: every 2–3 months, more for glass doors in busy households. Minimum twice a year for any home.
Does cleaning windows more often damage them?
No — the opposite. Regular cleaning prevents acidic droppings, sap and mineral deposits from permanently etching the glass. Infrequent cleaning is what shortens a window's good years.
Do dirty windows really block light?
Yes — accumulated grime and traffic film measurably reduce light transmission through glazing, which dims interiors and trims winter solar warmth.
What's the easiest way to keep windows clean year-round?
Reduce the effort per clean: a robot window cleaner handles each pane automatically at a button-press, making a monthly schedule realistic for busy households.
Make frequency free: CleanBot R1 robot window cleaner — £173, 24-month warranty, free UK delivery over £75.