The short answer
Self-cleaning conservatory glass can be worth it where the roof is awkward to get at, because the coating makes light dirt easier for rain to rinse away. It does not remove everything, and it does not suit every roof. Bird mess, sap and heavy moss still need washing off, so think of it as less cleaning, not none.
What the coating on self-cleaning glass actually does
The glass carries a very thin coating on its outer face, applied at the factory. It works in two stages. In daylight, the coating reacts with the dirt that has settled on the surface and starts to loosen it. When it rains, water spreads across the glass in a sheet rather than beading, and carries the loosened dirt away with it.
The result is not a glass that never gets dirty. It is a glass that holds dirt less firmly, so that routine grime from dust, pollen and light traffic film is washed off by ordinary rain. Because the effect is a surface treatment, it is only on the outside face of the roof glass. The inside needs cleaning like any other window.
One more practical point: the coating tends to sit on the outer face, so glass must be fitted with that face outwards. Units are marked, and a careful fitter checks the marking before each pane is lifted into place. A pane installed the wrong way round simply loses the benefit, and nobody will notice until the first summer of streaky glass.
We refer to this in general terms. Manufacturers differ in their coatings and in what they claim, and we do not quote figures for any of them here. Ask for the maker's own data on the specific unit being supplied.
Where self-cleaning glass falls short on a conservatory
The coating needs two things to work: daylight and rain. A conservatory roof has plenty of one and often too little of the other where it counts.
Sheltered and shaded roofs
A roof under a tree, or a lean-to tucked beneath an overhang or close to the house wall, gets less light, less rain or both. The coating does less in those spots, and the slopes where water does not run freely are the ones that stay dirty.
Shallow pitches
The rinsing relies on water running off. On a low-pitch roof, water lingers and dries in place, leaving marks. A steeper roof rinses better.
Overhanging trees
Under branches, the coating is up against more than it was designed for. Leaves, blossom, honeydew and bird droppings land in quantity, and the glass spends long periods wet and shaded. With trees close to the conservatory, the coating helps a little but does not remove the need for regular washing.
Stubborn dirt
Bird droppings, tree sap, leaf stains and moss are not the film the coating is meant for. They sit on the surface and need a brush and water. Seals and gutters also need clearing whatever the glass is made of, so the maintenance list shortens but does not vanish.
Looking after a coated roof without spoiling it
The coating is thin, and rough treatment shortens its working life. Wash with plenty of clean, tepid water and a sponge on a pole, adding a little mild liquid only if the grime needs it. Rinse thoroughly, because residue leaves a film that interferes with the coating. Avoid abrasive pads, scrapers, strong cleaners and pressure washers. Keep scaffolding poles and ladders off the glass.
If you have cleaning products that claim to work on glass, check the glass maker's guidance before using them. A cleaner that suits ordinary windows is not always right for a coated pane. Where we fit coated units, we give you the maker's cleaning instructions so you can follow them, and the handover is a good time to ask.
Weighing it up against other options
Self-cleaning glass is a glass roof option, so it is only relevant if glass is on your list. Polycarbonate cannot take the same factory coating, and a solid roof removes the need for it. Our guide to glass, polycarbonate and tiled conservatory roofs compares them.
For price, MyBuilder's 2026 guide gives £3,000 to £8,000 for a glass conservatory roof and does not separate out the coating, so a self-cleaning upgrade is covered in our written quote, priced on survey. Whether the saving in effort is worth that line depends on how difficult the roof is to get at. A long, high or awkward roof may justify it. A low one that you can wash from a ladder in half an hour may not.
Ask the supplier two questions before you pay for the upgrade: how the coating is guaranteed, and what cleaning products void that guarantee. The answers should be in writing, and we will pass on whatever the maker supplies with the units.
Heat and noise are separate issues. A coating does not cool the room, and a tinted or solar-control unit does that job. Our answer on noise in rain deals with the other common complaint.
What your insurer and your frame need to know
Replacing a roof with glass changes the weight on the frame, so we check the frame before agreeing to it. Glass is much heavier than polycarbonate, so a frame built for the lighter sheet may be asked to bear a good deal more. MyBuilder puts structural reinforcement at £500 to £2,000.
It is also worth telling your home insurer about a change from polycarbonate to glass. Our answer on conservatory roof insurance explains what to ask. For the whole job, see conservatory roof replacement in Stroud, where a survey comes first, the quote covers the whole job, and the finished work has a written 10-year workmanship guarantee.