Cleaning Guides

How to Clean uPVC Window Frames and Sills

One of the most common types of window frames nowadays is the uPVC. According to the British Plastics Federation, in the UK over 85% of the window replacement projects include uPVC materials. People prefer them more than any other type of window frames because of their durability and easy maintenance. The most popular colour choice for households in the UK are the white uPVC windows mainly because of the lower price.

However, they have one fault: the white frames and sills need to be cleaned a lot more often than the darker ones because of how visible all the spots are in comparison. Be that as it may, the occasional cleaning and rejuvenation is not a difficult task to accomplish, it doesn’t take a lot of time and efforts. Yet, it’ll make a major difference in the way your windows and the facade of your home look.

It’s advisable to clean your windows every two or three months. However, in case the window frames are visibly covered in dust and smeared, then you can wash them by following our step-by-step guide and practical tips. Keep in mind that if you regularly clean the uPVC windows, you’ll prolong their lifespan and efficiency.

Table of Contents:

How to clean uPVC window frames

Equipment that you will need:

  • Old towels/ dust sheet;
  • Ladder/ step stool;
  • Vacuum cleaner/ extendable feather duster/ old paintbrush;
  • Spray bottle;
  • Hot water;
  • Vinegar;
  • Microfiber/ cotton cloth;
  • uPVC Cleaner.

The best way to clean uPVC window frames:

  1. Lay down old towels or a dust sheet on the sill and on the floor to limit any damages.
  2. Step on a ladder or use a step stool to reach higher spots.
  3. Vacuum or brush with an extendable feather duster in every nook, around the hinge and the opening mechanism. Use the vacuum attachment with the soft brush to reduce the risk of scratching the uPVC frame. Or in case you don’t have one, use an old paintbrush to loosen any dust, dirt and cobwebs from the corners, then use the hose on the vacuum cleaner to clear it all away.
  4. Mix 1 cup of vinegar with 4 cups of hot water in a clean spray bottle.
  5. Spray the uPVC frames with the solution and leave it for 10 – 15 minutes to disintegrate the accumulated dirt.
  6. Wipe off the grime with clean microfiber cloths.
  7. Wipe off any excess water from the glass panel with lint-free cotton or microfiber cloth.
  8. Apply uPVC cleaner to polish the frames and restore their shiny look.
For any stubborn dirt, you can try a top grade solvent PVC cleaner, which can usually be purchased from a local hardware shop, but be careful not to use it on the silicone seals as they may begin to come off.
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How to rejuvenate uPVC window frames

To revive your weathered uPVC windows colour back to white you will need:

  • uPVC Restorer;
  • Microfiber cloths;
  • Sponge cloth;
  • Bucket;
  • Water.

If you have recently cleaned your window frames, but you still feel the need to polish and rejuvenate them, follow these steps:

  1. Wipe off any surface debris with a wet microfiber or sponge cloth before applying the uPVC Restorer. In case you haven’t thoroughly cleaned the frames from grease and dirt beforehand, then follow the foregoing cleaning procedure.
  2. Pour the uPVC Restorer onto a dampened cloth and work it into the surface. Apply to one single section at a time. Polish off with a clean and dry microfiber cloth.
  3. Clean off any stains left from the uPVC Restorer on the glass around the frames by using a clean wet microfiber cloth.
Try to avoid working in direct sunlight as this will cause the product to evaporate quickly thus making it more difficult to polish the frames to a shine. If you have no other choice, apply the product quickly and polish off right away. Repeat the rejuvenating process on each individual section of the frames until the job is complete.

What to avoid when cleaning uPVC surfaces?

  • Avoid using coloured synthetic cloths because you’re risking of colouring the plastic surface when applying the cleaning solution. Forget about using any caustic cleaning agents or abrasive creams, sponges and scouring pads.
  • You should never use bleach because it will discolour the uPVC window frames. Even small doses will cause a chemical reaction with the glossy surface of the plastic, creating a dull matt effect that can never be undone.
  • Another thing that will immediately ruin your frames are cellulose thinners because they will melt the plastic. Another product not suitable for the purpose is WD40, along with nail polish remover, methylated spirits and white spirits.
Under no condition you should use paint to conceal discolouration, streaks or accumulations of mildew and dirt on any of your uPVC window frames.

How to clean uPVC window sills

In case it’s been some time since you last cleaned your window sills and you need a more thorough technique, here is what you can do:

Window sills cleaning tools:

  • Vacuum cleaner;
  • Baking soda;
  • A spoon;
  • White vinegar;
  • Toothbrush;
  • Paper towels;
  • Spraying bottle;
  • Lukewarm water;
  • Dish soap;
  • 2 microfiber clothes.

How to remove stains from uPVC window sills:

  1. Vacuum any debris from every nook and cranny using the appropriate vacuum cleaner attachment suitable for narrow spaces.
  2. Sprinkle the baking soda along the window sill. Make sure to get it in all of the corners where dirt accumulates the most. Apply as much of the soda as necessary and try to cover the whole surface of the sill. Use a spoon so you can distribute it evenly.
  3. Gently pour the white vinegar down into the window sill. The acid in the vinegar will quickly react with the baking soda. Leave it for two minutes so that the mixture will have time to disintegrate the accumulated grime.
  4. Start scrubbing the sill with the toothbrush to loosen up the dirt. Don’t forget to scrub into the corners because there always are stubborn stains that need more special attention.
  5. Soak up all of the dirty liquid with paper towels.  
  6. Add a spoon of dish soap into a spray bottle filled with lukewarm water. Apply the mixture along the sill to clean up the extra dirt left behind. Wipe it with a microfiber cloth and polish off with another clean cloth.
uPVC windows are easy to maintain. For best results vacuum the tracks and the sills every two weeks. Use the universal cleaning solution: a mix of water and white vinegar and polish them with a microfiber cloth.

Check all of the window cleaning solutions we offer by visiting our main website.

How to clean mould off your uPVC frames and sills

Mould is extremely hazardous for your health. It is a major risk for:

  • Babies, children and elderly people;
  • People with respiratory problems like allergies and asthma;
  • Those with existing skin disorders, such as eczema;
  • People with a weakened immune system, such as those having chemotherapy.

The danger is quite real as it’s enough to only inhale or touch mould spores in order to get an allergic reaction or an asthma attack. Specialists advise all people vulnerable to mould and damp exposure to stay away from such places.

One of the most common areas where we see mould build-up is on and around the windows. Many people struggle with this problem, so here are the steps on how to remove mould from your uPVC window frames and sills.

Equipment for cleaning black mould on uPVC window frames:

  • Plastic dust sheet;
  • Safety goggles;
  • Gloves;
  • Dust mask;
  • Vacuum cleaner;
  • Rubbing alcohol;
  • Cleaning cloths;
  • White vinegar;
  • Baking soda.
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Cleaning uPVC window frames mould in 7 simple steps:

  1. Cover the sills and the floor with a plastic dust sheet to catch any falling mould spores. Then open the window for better ventilation.
  2. Put on safety goggles, gloves and a dust mask to protect yourself from any released spores in the air.
  3. In case the window frames and sills are dry, remove any loose spores with a vacuum cleaner by steadily running the nozzle of the hose over the glass, the frames and the sill. When finished, sanitize the vacuum cleaner extension with rubbing alcohol.
  4. If the area affected by black mould is wet, wipe the frames and sills with a dampened cloth to remove the excess spores.
  5. Spray the frames and sills with white vinegar and leave it for at least 5 minutes.
  6. Sprinkle baking soda on a cleaning cloth and rub it in the areas affected by the mould. The acidity of the vinegar and the abrasiveness of the soda will kill the spores and clean them from your uPVC windows.
  7. Wipe the surface with a clean dry cloth.
If the problem with the gathered mould on your uPVC window frames and sills is more extensive, then you’ll need to use specialised mould and mildew remover. Be careful when buying such cleaning solutions and always follow the instructions. You need to select one that is appropriate for cleaning uPVC surfaces, otherwise, you’re risking of damaging your windows.

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Here are some final thoughts and takeaways to consider when cleaning uPVC window frames and sills:

  • Avoid using strong chemical solutions and abrasive materials. The best way to wash uPVC window frames is by mixing your own homemade window cleaner using only water and white vinegar.
  • Vacuum at least twice a month your window sills to prevent the accumulation of dirt and save more time when doing your seasonal window cleaning.
  • Always use protective gear when cleaning mould off window frames to prevent any allergic reactions and poisoning.
  • To remove mildew from uPVC windows use vinegar and baking soda instead of strong chemicals to prevent any damages to the windows.

Image source: Depositphotos/


If you know other methods for cleaning uPVC window frames and sills, please do share in the comment section. That way you may help others who are searching for the appropriate cleaning solution.

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