A window is not one surface. The uPVC frame, the glass, the gaskets, the hardware and the drainage channels each want different treatment, and the single answer everybody gives, warm soapy water, is correct for exactly one of them. Get the frame and glass right, keep solvents away from everything else, and leave one part unlubricated on purpose.
Match the product to the surface rather than reaching for one bucket.
Two of those rows carry warnings worth stating plainly rather than tucking into a caveat.
Our own product guide is explicit that petrol, paint thinner and other solvents containing ammonia must never touch painted or treated surfaces. There is a narrow exception: solvent-based residue removers lift leftover adhesive or silicone smears from the glass itself. Keep them on the glass, off the frame, and off the gaskets, and ventilate the room.
For aluminium, the pH range matters. Our guide specifies pH-neutral cleanser between 5 and 8, and recommends washing the aluminium every time you wash the windows, because washing is itself what protects the finish.
Cleaning keeps a window looking right. Maintenance keeps it working. Five jobs cover the second, once a year.
Our guide sets the lubrication interval at least once a year, using all-purpose oil, and it names the parts: hinges, handles, rivet joints, espagnolette locks, slide bars, roller bolts, slots and locks.
Horizontal mouldings appear in that list for a reason. They take the most wind and water of any part of the frame and wear faster than the rest, so they are where damage shows first and where a yearly look is worth most.
One commercial note. Our warranty excludes damage resulting from insufficient maintenance, which makes the annual routine a term of the cover rather than a suggestion. It takes under an hour for a whole house.
Most maintenance guides tell you to spray every moving part, and several name silicone spray or a drop of light oil for the hinges. On a window fitted with a friction brake, that advice damages the thing it is meant to help.
Our product guide is specific: on sashes with friction brakes, or with concealed side swing and reversible hardware, the slide rails must be kept clean, oil-free and free from paint.
The reason is mechanical. Friction is what holds the sash open at the angle you leave it. Lubricant on a friction rail removes the friction, and the window then swings in the wind or falls shut. You have not maintained it, you have disabled it.
So the rule splits in two. Lubricate the hinges, handles, espagnolettes, roller bolts and locks. Keep clean and dry the friction brake rails and concealed reversible hardware rails. If you are unsure which is which, our window adjustment guide identifies the hardware by window type.
Clean them in place with ordinary detergent and a cloth, and leave them there. Our guide is direct on the second half of that: do not remove weather stripping. It sits in a groove around the sash perimeter and it is doing a job that a replacement strip pushed back in by hand rarely does as well.
Skip the silicone dressings. Several maintenance guides recommend spraying seals to keep them supple, and our guide takes a different position: glazing seals do not require maintenance, but they should be inspected at least once a year, especially at the bottom of the unit.
Inspection is the useful part. Soft and flexible is healthy. Torn, cracked or flattened means the seal has reached the end of its life, and our guide recommends replacing the glazing beads at the same time as the seals rather than separately.
That is the honest sequence: clean, inspect, replace when they fail. A dressing that makes a perished gasket look better postpones a diagnosis rather than extending a life.
Some window types are built for exactly this, and the answer depends on which you have.
Reversible windows rotate 180° so the outer face turns inward. A safety device locks the sash at the 180° position, and you clean the outside standing in the room. Top guided reversible windows have a second safety device that locks the sash at about 10°, which you release to open it further.
Side guided windows open to 90° and leave a gap of around 15cm between sash and frame, wide enough to reach through and clean the outer pane.
Side swing reversible windows rotate 180° as well. One warning from our guide: that rotation is designed for cleaning only and should not be used as a ventilation position.
If your windows are none of these, the outside face needs reaching from outside. On upper floors that means a pole system or a window cleaner rather than a ladder and a bucket.
Four specific problems account for most of the searching, and two of them have honest answers people do not want.
Rust marks. Usually run-off from something metal above the window, a bracket, a fixing or a hanging basket. Warm water and detergent lifts fresh marks. Do not reach for a rust remover: the acid in it damages uPVC and gaskets. Fix the source or the marks return.
Mould on frames and seals. Detergent and a soft brush, then address the cause, which is condensation rather than dirt. Mould on window seals is a humidity signal, and our condensation guidance covers the ventilation side.
Scratches. Not removable without abrasives, and abrasives cause worse damage than the scratch. On aluminium surfaces our guide describes a repair by sanding and applying metal paint, and states plainly that this type of repair will always be visible.
Deep scratches are a cosmetic fact rather than a fault.
Yellowed uPVC. Cosmetic, permanent, and not improved by any of the whitening products sold for it. Chemical whiteners work by attacking the surface, which leaves it more porous and quicker to discolour again. Yellowing affects nothing about how a window performs, and painting is the only real change of appearance available. Our guide to painting uPVC covers what that involves.
