Glass is the most honest surface on a building: it's either clean or it visibly isn't. Storefronts sell through it, offices light through it, and a building's overall impression rides on it. This guide covers how often commercial windows actually need cleaning, the methods professionals use, and the issues — like hard-water staining — that catch building owners by surprise.
How Often Should Commercial Windows Be Cleaned?
- Street-level storefronts: Monthly is the common baseline; high-touch retail and food service often go biweekly or weekly for entrance glass.
- Office buildings (low/mid-rise): Quarterly exterior cleaning is typical, with interior glass on the janitorial cycle.
- Restaurants: Entry and dining glass monthly or better — guests sit inches from it.
- Auto dealerships: Showroom glass exists to disappear; monthly exterior with frequent touch-ups is the norm.
- Coastal, high-dust, or construction-adjacent sites: Step frequency up; salt air, dust, and site debris soil glass measurably faster.
The Methods Professionals Use
- Traditional squeegee work: Mop and squeegee with professional solution — still the standard for storefronts, interiors, and detail work, leaving glass spotless and dry immediately.
- Water-fed pole systems: Purified water and brush on telescoping poles for exterior glass up to several stories — safe, efficient, and spot-free as the pure water dries.
- Detail work: Frames, tracks, sills, screens, and mullions on request — the difference between clean glass and a clean window system.
Hard Water Stains: The Problem Mopping Can't Fix
White, cloudy mineral staining — usually from sprinkler overspray or runoff across the glass — etches into the surface over time and ignores ordinary cleaning entirely. Caught early, specialized mineral-removal treatment can restore the glass; left for years, staining can become permanent etching that only replacement fixes. Two practical defenses: adjust sprinklers away from glass, and treat staining when it first appears rather than after it matures.
Safety and Building Programs
Window cleaning above ground level is safety-regulated work: appropriate equipment, trained personnel, and methods matched to building height and access. For low- and mid-rise commercial buildings, modern pole systems have made much of this work ground-based and dramatically safer. When building a program, the practical structure is a fixed rotation — monthly storefront, quarterly full-exterior, interior on the janitorial cycle — with pricing per rotation so the schedule runs itself.