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Self-cleaning glass — Pilkington Activ & Saint-Gobain Bioclean
A microscopic photocatalytic + hydrophilic coating that breaks down organic dirt and lets rainwater rinse it away in a sheet rather than droplets. Self-cleaning glass cuts the hand-cleaning frequency on hard-to-reach surfaces — conservatory roofs, atrium glazing, balustrades, high-level windows, coastal-facing facades — by an order of magnitude. Pane Relief supplies Pilkington Activ (standard and Activ Blue solar-control), Saint-Gobain SGG Bioclean (coastal-grade, salt-spray resistant), and matching DG / TG sealed units with the self-cleaning coating on surface 1 (the outside-facing surface) and low-E typically on surface 3.
Conservatory roof or hard-to-clean glass
If you spend Saturdays on a ladder cleaning the conservatory roof — or pay a window cleaner monthly to do it for you — self-cleaning glass pays for itself in three to five years. Free UK mainland delivery, 7-10 working days on stock spec, 5-year warranty on the coating performance (separate to the standard 10-year edge-seal warranty).
Configure my unitConservatory installer, glazier, builder
Self-cleaning is the default upsell on every conservatory roof we ship — a no-brainer for the homeowner if you frame it as "your installer comes back for a service visit, not a re-clean". Net 30 trade terms, tier discount on 5+/20+ unit orders, scheduled delivery to your install date. Spec is identical to standard low-E DG/TG except for the surface 1 coating.
Trade pricing & bulk ordersWhere self-cleaning glass works best
Coating needs UV light and rainwater to do its job — south-facing, exposed, hard-to-reach surfaces are the sweet spot.
Conservatory roof
The classic application. Activ Blue adds solar-control (g-value 0.42) to keep summer overheating in check.
Glass balustrades & balcony
Frameless balustrades collect handprints fast — self-cleaning keeps them clear with normal rainfall.
High-level / atrium glazing
Inaccessible windows above stairwells or in double-height rooms. Cuts the need for cherry-picker cleans.
South-facing facade
UV-driven photocatalytic reaction needs sunlight. South-facing maximises performance year-round.
Coastal property (Bioclean)
Saint-Gobain Bioclean is salt-spray resistant — designed for properties within 1km of the sea.
Commercial shopfront
Reduces cleaning contractor visits. Particularly valuable on multi-storey or curtain-wall installations.
How self-cleaning glass actually works
Two coating effects — photocatalytic and hydrophilic — working together. Here's the mechanism, in plain terms.
The two-stage process
- Photocatalytic stage — UV light from the sun activates the titanium dioxide (TiO₂) coating, which breaks down organic dirt (pollen, sap, bird droppings, atmospheric soot) into loose carbon dioxide and water.
- Hydrophilic stage — When it rains, water spreads in a continuous sheet across the surface (rather than forming droplets) and rinses the broken-down dirt away cleanly, leaving the glass to dry without streaks.
- Activation time — The coating "wakes up" within 5-7 days of fitting; needs UV exposure to start working. Cloudy days still provide enough UV to maintain activation.
- Inorganic dirt (mineral deposits, hard-water scale) is not broken down by photocatalysis. Annual hand-clean recommended for that, but typically only once a year vs monthly for standard glass.
Pilkington Activ vs Saint-Gobain Bioclean
Pilkington Activ — The original mass-market self-cleaning glass. Activ Clear for north-facing or non-overheating applications; Activ Blue adds a subtle blue tint and solar-control low-E to combat summer overheating in conservatory roofs.
Saint-Gobain SGG Bioclean — Coastal-grade alternative, salt-spray resistant and recommended for properties within 1km of the sea. Slightly higher unit cost but materially better corrosion resistance on the coating itself.
Self-cleaning glass — common questions
Q: Does self-cleaning glass really work, or is it marketing?
It really works — but with caveats. The photocatalytic + hydrophilic mechanism is well-documented (Pilkington Activ was launched in 2001; the technology is 25 years mature). In south-facing, exposed, regularly-rained-on installations, hand-cleaning frequency drops from monthly to roughly annually. In north-facing, sheltered, or low-rainfall installations the effect is muted — the coating still helps but the gains are smaller. It is not a "never clean" product, and inorganic mineral deposits still need an occasional hand clean.
Q: Where does it work best?
South-facing, exposed, hard-to-reach is the sweet spot. Conservatory roofs are the textbook application — exposed to UV, rain-washed, awkward to clean by hand. Glass balustrades, atrium glazing, and high-level facade panels are the next-best applications. North-facing or sheltered (under deep overhangs, beneath trees) get less UV and less rainfall, so the cleaning benefit is reduced.
Q: Will it work on the inside of the glass too?
No — the coating only works on surface 1 (the outside-facing surface, exposed to UV and rain). Internal condensation, fingerprints on the inside of the pane, and dust accumulation on the indoor side still need conventional cleaning. Self-cleaning is an outdoor-only effect.
Q: I live near the sea — does self-cleaning glass survive salt spray?
For coastal properties, specify Saint-Gobain SGG Bioclean rather than Pilkington Activ. Bioclean's coating is engineered for salt-spray resistance; we recommend it for any property within 1km of the sea, or on exposed cliff-top / harbour-front installations. Activ will still work but the coating durability is materially shorter in saline conditions.
Q: How is self-cleaning combined with low-E?
The self-cleaning coating is on surface 1 (outside face of the outer pane). The low-E coating is typically on surface 3 (inside face of the inner pane, facing the cavity). They don't conflict — most modern self-cleaning sealed units are dual-coated (self-clean on 1 + low-E on 3), giving you both effects in one unit with no compromise on either.
Q: Does it cost a lot more than standard glass?
Self-cleaning adds approximately 15-25% to the cost of an equivalent low-E sealed unit. On a conservatory roof, that's typically £30-£60 per square metre. Payback against a window cleaner visiting monthly (typical UK rate £6-£12 per visit on a conservatory) is 3-5 years. Configurator gives the exact uplift live as you toggle the coating option.
Q: Will rain leave water spots on the glass?
The opposite, in fact. Standard glass beads water into droplets that dry into spots; self-cleaning glass spreads water in a continuous sheet that runs off cleanly and dries without streaks. After heavy rain, self-cleaning glass typically looks cleaner than it did before. In drizzle or fine rain, the sheeting effect still works but slower. In very hard-water areas (limescale-prone) we still recommend an annual hand-clean for mineral deposits.
Q: How long does the coating last?
The coating is pyrolytically bonded to the glass at manufacture (not a sprayed-on film), and is permanent for the life of the glass — typically 25-30 years. We warrant the coating performance for 5 years against optical defect or failure of the self-cleaning effect; in practice, the coating outlasts the warranty by a wide margin. Don't use abrasive cleaners or scrapers — they'll damage the coating.
Q: Is self-cleaning available on triple-glazed units?
Yes — Activ and Bioclean are both available on triple-glazed sealed units with self-cleaning on surface 1 and low-E coatings on surfaces 3 and 5. Common spec for high-end conservatory roofs and Passive House projects with hard-to-reach roof glazing.
Related ranges and guides
Hate ladder-cleaning the conservatory roof?
Configure a self-cleaning replacement unit in 60 seconds. South-facing roofs see the biggest gain. Helpline 0117 330 3057.