How to Clean uPVC Window Frames Without Damaging Them

To clean uPVC window frames without damaging them, you need warm water, a little washing-up liquid and a soft cloth. Abrasive products and bleach are the main things to avoid, because they can leave permanent scratches or turn white plastic brown. Regular gentle washing keeps the frames bright and stops dirt from staining the surface.

How often uPVC frames need cleaning

Window manufacturers recommend a regular wash to keep uPVC bright and in good condition. The correct frequency depends on where you live and how much pollution or salt is in the air.

The table below shows how often manufacturers advise washing uPVC frames.

This is one window maker's advice, so check whether the company that fitted your windows gives its own.

What you need for the job

You do not need specialist equipment to clean uPVC safely. The best tools are simple household items that will not scratch the plastic or strip its finish.

• Gather a soft brush to remove loose dust and cobwebs.
• Prepare a bucket of warm water mixed with a squirt of washing-up liquid or a liquid window cleaner poured from a bottle, rather than a spray.
• Find several soft cloths for washing and drying the frames.
• Keep a non-scratch sponge handy for the outside sills.
• Bring a vacuum cleaner with a soft brush attachment to clear dust out of the hinges.

If you buy a dedicated uPVC cleaner, check the label to ensure it is compatible with your frames. You must test it on a small, hidden area first to make sure it does not cause discolouration.

Cleaning the outside of the frames

Cleaning the outside frames requires a gentle approach to lift dirt without pushing grit into the plastic. You should never use a pressure washer near your windows, as the force of the water can weaken the seals and cause leaks. You should clean ground floor windows from the outside, but never climb ladders or lean out of upper windows to reach the frames, and never go onto a flat roof or a conservatory roof.

1. Brush off all dust, cobwebs and loose dirt with your soft brush or a dry cloth.
2. Rinse the frames and sills with a garden hose if you have one available.
3. Wash the uPVC using your soft cloth and the warm soapy solution, working from the top down.
4. Use a non-scratch sponge on the sills, soaking stubborn dirt with the soapy water and leaving it for five minutes before rubbing again.
5. Rinse the frames and sills thoroughly with clean water to remove all soap residue.

Cleaning inside the frames, hinges and sills

The inside of your window frames gathers dust, dead insects and moisture. You need to clear the mechanism carefully to keep the window opening smoothly.

1. Open the window as far as the point of resistance and do not push past it.
2. Vacuum dust and debris out of the hinges using the soft brush attachment.
3. Use the vacuum around the inside of the frame and deep into the corners.
4. Clean the inner frame and sill with a soft cloth and your warm water and mild soap solution.
5. Keep the window hinges lubricated by applying a few drops of multi-purpose oil.

Products that damage uPVC

Many common household cleaning products can damage uPVC frames, and some of that damage cannot be reversed.

• Bleach can permanently discolour white uPVC and can turn it brown.
• Cream cleaners and scouring powders contain abrasives that leave fine scratches, making the surface dull for good.
• Steel wool and scouring pads scratch the plastic deeply and remove the smooth finish.
• Cellulose thinners melt the plastic entirely.
• Methylated spirits and white spirit strip the surface and cause lasting damage.
• Caustic or ammonia based cleaners should not be used on uPVC.
• Standard glass cleaner should not be used on the frames.
• Certain coloured detergents contain dyes that can stain the white surface permanently.
• WD40 should not be used on uPVC.

If your frames have been dulled by years of using cream cleaners or scouring pads, they cannot be made shiny white again.

Can yellowed uPVC be made white again?

Older or cheap white uPVC can yellow with age. If the yellowing is a manufacturing or quality issue, very little can be done to restore the original colour. The plastic itself has changed, and no amount of scrubbing will turn it white.

If the discolouration is caused by a heavy build-up of grime rather than age, a natural acidic solution can help lift it. You can mix one cup of vinegar with four cups of hot water. Spray this mixture onto the frames, leave it to sit for ten minutes, and then wipe it off with a clean cloth. This method breaks down grease and dirt without scratching the plastic.

Dealing with mould on frames and seals

Condensation often leads to black mould forming along the edges of the glass and on the window seals. You must clean this carefully to avoid spreading the spores or damaging the rubber.

Start with a hot water and soap solution and a soft cloth. If the mould does not lift, try the vinegar and hot water mixture. You must never use bleach or white spirit to remove mould from your windows.

The government guidance on damp and mould states that mould can be removed from hard surfaces with an appropriate cleaning product and left to dry completely. For health and safety reasons, you should use dedicated mould and mildew products in preference to bleach.

When cleaning mould, wear a mask, gloves and goggles to protect yourself. Keep your internal doors shut and open the windows during and after cleaning to ensure good ventilation. Most people can be expected to deal with condensation and very small amounts of mould themselves, but larger areas should be handled by professionals.

Simple maintenance that keeps windows working

Regular cleaning is the best time to check that your windows are working properly. Very hot or cold weather can make uPVC frames expand or shrink, which sometimes causes them to stick. If a double glazed window becomes stiff, you should first try oiling the mechanism, hinges and handles. You can also try adjusting the screws to tighten any loose hinges.

Double glazing often comes with a warranty of 10 or 20 years, and some companies give a lifetime guarantee. If your window remains stuck after oiling, contact the company that fitted it. You should not try replacing a lock yourself, as this is likely to void your warranty.

Sometimes a window is beyond simple maintenance. Signs that your double glazing may need replacing include draughts, leaks, excessive noise from outside, cracking timber or yellowing uPVC. You should also look for visible damage to the seals, windows that are hard to open, close or lock, and frequent condensation appearing between the two panes of glass.

What a window cleaner will and will not do

If you hire a window cleaner, they will usually clean the outside frames as part of their normal service. Many window cleaners now work from the ground using a water-fed pole. This involves a telescopic pole with a brush head, fed with purified water from a tank in their van or a trolley.

During a pole clean, the glass, frames and sills are scrubbed, rinsed and left wet. Because the minerals have been filtered out of the water, it is meant to dry without marks. A first pole clean can sometimes leave a little spotting until old residue has been rinsed out, so you should avoid judging a pole clean entirely on the first visit.

Traditional cleaning uses an applicator, squeegee and cloth. Industry guidance produced with the Health and Safety Executive says water-fed poles must not be used near overhead power lines. You should point out any overhead cables to the cleaner before they start work.

Interior window cleaning is usually treated as an extra service. Adding the inside of the main windows to a regular clean typically costs between £10 and £15. Conservatory roofs, roof windows, glazed doors, fascias and gutters are also priced on top of a standard clean.

The table below shows what is typically included in a clean and what is charged as an extra.

These are typical published prices and inclusions for 2026. You should always confirm what is included in a regular clean before agreeing to a price, as local quotes will differ.

Hiring a window cleaner safely

Most domestic window cleaning is done on a round, meaning the same cleaner returns on a set cycle, commonly every four, six or eight weeks. Work is priced per visit according to the size of the property, the number and type of windows, access and frequency, rather than by the hour. A first clean or a one-off clean usually costs more than a regular visit. Prices are generally higher in London and the South East.

You should check that a cleaner has public liability insurance. This is not a legal requirement, but it is the cover that pays out if the cleaner damages your property or injures someone, so you should ask to see a current certificate. Employers' liability insurance is compulsory for any business that has employees. The Federation of Window Cleaners is a non-profit trade body with a safety accreditation scheme, a code of practice and training. Membership is voluntary, so you should treat it as one good sign among several.

Under the Consumer Rights Act 2015, a service must be carried out with reasonable care and skill. If it is not, you can ask for it to be put right or request your money back. A quote is a fixed price, whereas an estimate is not. If you agree to a service on your doorstep, by phone or online, it normally carries a 14-day cooling-off period.

You should watch out for cold callers who claim to be your usual cleaner and ask for payment. You should also avoid cleaners who carry out work without agreement and then post a bill, or those who ask you to pay months in advance.

Do not worry if a cleaner uses ladders. The Health and Safety Executive says ladders can be a sensible option for low risk, short duration work, including domestic window cleaning on lower floors. The law asks for competence rather than a formal qualification. In Scotland, most councils require window cleaners to hold a licence, and licence holders carry identification. Requirements vary by council.

Common questions

How to clean white uPVC window frames?

You should wash white frames with warm water, a little washing-up liquid and a soft cloth. Never use bleach to clean white uPVC, as it can cause a chemical reaction that turns the plastic brown permanently.

What is the best cleaner for uPVC window frames?

The safest cleaner is a simple mild soap solution. If you decide to buy a dedicated uPVC cleaning fluid, you must check that it is compatible with your frames and test it on a small, hidden area first to ensure it does not stain.

Can you use glass cleaner on the frames?

Window manufacturers advise against using standard glass cleaner on uPVC frames. You should stick to warm soapy water and a soft cloth for the plastic parts of your windows, as glass cleaning chemicals can damage the finish.

Why are my double glazed windows stiff?

Very hot or cold weather can cause uPVC frames to expand or shrink, making them stick. Stiff windows can also be caused by dry hinges, so try applying a few drops of multi-purpose oil to the mechanism before calling a repairer.

Next steps

Before you clean your frames or hire someone to do it, follow this checklist to protect your windows.

• Check your cupboards for soft cloths, a non-scratch sponge and washing-up liquid.
• Remove any bleach, cream cleaners or scouring pads from your cleaning kit.
• Test any dedicated uPVC cleaning products on a hidden area of the frame first.
• Ask any professional window cleaner to confirm exactly what is included in their quote.
• Ask to see a current public liability insurance certificate before a cleaner starts work.

Keeping your window frames clean stops dirt from staining the plastic and keeps the hinges working smoothly. If you would rather leave the job to a professional who has the right equipment and insurance, you can find a window cleaner near you to get a fixed quote for a regular round.