Self-cleaning by the chemistry of UV + rain. A 28mm double-glazed sealed unit with a Pilkington Activ self-cleaning outer pane and a Planitherm Total+ Low-E inner pane, argon-filled, delivering A-rated thermal performance while dramatically reducing the frequency of external glass cleaning. Pilkington Activ is the original self-cleaning glass — launched in 2002, now the dominant UK self-cleaning specification on residential and commercial new-build. The self-cleaning mechanism is two-stage: photocatalytic + hydrophilic. The outer pane carries a microscopically thin titanium-dioxide (TiO₂) coating that, when exposed to UV from daylight, breaks down organic dirt (bird droppings, leaf residue, atmospheric grease, algae spores) via a photocatalytic redox reaction. When it rains, the TiO₂ surface becomes hydrophilic — water spreads as a sheeting film rather than beading into droplets — and the loosened dirt is rinsed away with the sheeting flow, leaving a streak-free finish without mineral spots. Technical specification Overall thickness 28mm Build-up 4mm Pilkington Activ outer (TiO₂ coating face 1) / 20mm argon cavity / 4mm clear with Planitherm Total+ soft-coat (face 3) Outer coating Pilkington Activ — pyrolytic titanium dioxide, applied on float-line during glass manufacture (permanent, cannot wear off) Gas fill 90% argon (BS EN 1279-3) Spacer bar Warm-edge composite, black U-value (centre-pane) 1.1 W/m²K g-value 0.61 Light transmittance ~77% BFRC Window Energy Rating A (in compliant frame) Self-cleaning activation UV-A daylight (works even on overcast UK winter days; faster cycle on bright south-facing aspects) Standards BS EN 1279, BS EN 673, BS EN 410, Pilkington Activ datasheet (Pilkington publication 8005) Where this unit is the right call Hard-to-clean window locations — first-floor and upper-storey externals, dormer windows, conservatory roof panels, gable-end and apex glazing, atrium glazing, and any window where access for cleaning is awkward or costly. Bird-droppings prone aspects — windows beneath tree canopies, near garden features that attract birds, coastal aspects with gull activity. The photocatalytic effect breaks down the organic guano faster than it can stain. Pollen and tree-sap exposed locations — sycamore, lime, and oak tree drip-zone glazing where standard glass becomes spotted within weeks. Commercial and rental property where cleaning costs are recurring — letting agents and facilities managers find the maintenance cost reduction justifies the spec uplift within 3-5 years. A-rated WER + self-cleaning in one spec — Building Regs L compliance plus low maintenance, the standard residential new-build self-cleaning brief. For coastal aspects where salt film is the dominant cleaning issue, the Saint-Gobain Bioclean Self-Cleaning Coastal Unit has better salt-rinse performance in field testing. For the dedicated self-cleaning topical context, see the self-cleaning glass topical page. For standard non-coated A-rated, the 28mm Low-E A-Rated Double Glazed Unit is the cheaper alternative. Stock sizes and pricing Five UK-standard stock sizes below. Dispatch 7-10 working days from order. The Pilkington Activ outer pane adds £35/m² flat over the equivalent uncoated Low-E build — the configurator routes custom sizes via the same per-m² rate. Trade accounts: tiered volume pricing on log-in. Certification and standards UKCA mark, BS EN 1279 Declaration of Performance, Pilkington Activ outer-pane authentication certificate (sealed unit identifies coated pane orientation), argon-fill certificate, Planitherm low-E coating identification, and a Letter of Conformance referencing the Pilkington Activ technical datasheet for the self-cleaning performance claim. For commercial spec-sheets, we supply the full Pilkington Activ life-cycle assessment on request. Frequently asked questions Does it actually clean itself, or do I still need to wash it? It cleans itself of organic dirt (bird droppings, leaf residue, pollen, atmospheric grease, algae spores) and rinses to streak-free with rainfall. It does not remove paint splatter, builder's-grade silicone smears, or mineral spots from hard-water borehole spray — those need manual cleaning. The realistic claim: 80-90% reduction in cleaning frequency, not 100% elimination. Does it work in shade or in winter? The photocatalytic reaction needs UV-A, which is present even on overcast UK winter days at 5-15% of summer levels. North-facing windows in deep shade still receive enough UV to maintain the cycle, just slower (a north-facing dirt cycle that resets in a week south-facing might take 2-3 weeks north-facing). For sustained efficacy, daylight (not direct sunlight) is sufficient. Will the coating wear off over time? No. Pilkington Activ is a pyrolytic coating, applied at the float-glass production stage at ~600°C — the titanium dioxide is fused into the glass surface molecular structure. It cannot be wiped off, scratched off, or weathered off. The performance claim is for the lifetime of the glass. Can I use cleaning products on it? Yes, but you usually don't need to. If you do wash externally, use clear water with a soft sponge — no detergent, no vinegar, no abrasive cloth. Glass-cleaning fluids deposit residues that interrupt the photocatalytic cycle until the next rain. Avoid silicone-based glass treatments (Rain-X and similar) — they coat over the Activ layer and block the photocatalytic mechanism. How does it compare to Saint-Gobain Bioclean? Activ and Bioclean are both pyrolytic TiO₂ self-cleaning coatings with very similar performance specs. Activ is the original (Pilkington, launched 2002) and dominates the UK residential market. Bioclean (Saint-Gobain, launched 2003) has marginally better field-test performance in coastal salt-film conditions. For inland aspects, either works; for coastal, prefer Bioclean. See the Bioclean Coastal flagship. Lead time and warranty? 7-10 working days dispatch. 10-year warranty on edge-seal integrity, argon retention, and Low-E inner-pane performance. The Pilkington Activ outer coating is covered by Pilkington's own 10-year performance warranty (passed through to end-user via our supply chain). Does it work on conservatory roofs? Yes — and arguably this is where self-cleaning glass earns its keep most. Conservatory roof panels are nearly impossible to clean from below and dangerous to clean from above. Activ keeps the panels clear of organic deposits without ladder access. For conservatory-specific specifications, the configurator includes a "conservatory roof glazing" option that lifts the toughened-outer requirement (BS EN 12150) automatically.
Related
Related
Related
Related