How To Clean Low E Glass Without Damaging It

As a professional window cleaning and after builders cleaning company, we are required to continually work with glass suppliers to ensure we are up to date with the latest glass technology. One type of glass which is becoming increasingly common when it comes to new home construction in Sydney is Low E Glass.

It’s made the same as standard glass but has a thin metallic oxide film fused to one side of it (usually facing inside) and this coating can be an inexperienced window cleaners worst nightmare.

The glass was originally used in commercial office buildings due to it’s ability to increase energy efficiency (by reducing heat loss) and is starting to become a popular choice for residential homes (prevalent in new homes built in Sydney’s North Shore) due to it’s ability to reduce the amount of UV rays, heat and glare coming into the home when compared to standard glass.

The outside of Low E Glass can be cleaned like standard glass (eg. Squeegee) but the insides requires special care due to the metallic oxide coating.


cleaning low e windows
cleaning low e windows

DO NOT use the following things on the metallic oxide coating –

  • Abrasive Cleaners
  • Ammonia based products
  • Powder based cleaners
  • Alcohol based products
  • Harsh Alkali  or acid based cleaners (unless under special circumstances outlined below)
  • Scrapers, Blades or Squeegees
  • Metal based objects like scourers

Routine Cleaning

Follow this process for general routine cleaning to remove dust and fingerprints by using one of the following cleaning solutions –

  • Plain water
  • Water with a little dish detergent (soapy water)
  • 10:1 Water to Vinegar Solution


  1. Use a spray bottle filled with water and spray generous amount onto the glass from top to bottom removing dust and dirt particles
  2. Fill another spray bottle with soapy water (dish detergent and water) and spray down the glass with it
  3. The 10:1 water to vinegar solution can be used instead of the soapy water if you have stubborn stains
  4. Rinse with a generous amount of plain water
  5. Remove excess water with a lint free cloth – The trick to having streak free Low E Glass is to leave a thin film of moisture on the glass after cleaning leaving it to evaporate (ensure it’s just a thin film, no drips!)

Spot Cleaning / Removing Stubborn Stains

The following products can be used safely on stains which can’t be removed after routine cleaning –

  • Denatured Alcohol
  • Mineral Turpentine
  • Acetone
  1. Wet a corner of a lint free cloth with one of the above solvents
  2. Use the cloth and gently rub the stain out – Be cautious of any  painted surfaces which could react negatively to the solvents

Removing Scratches / Stains Caused by Contact with Metal Objects

Never allow the low E coating to come into contact with metallic objects (blades, watches, rings, scourers etc) as it can leave behind deposits which show up on the glass as stains or scratches.


cleaning scratched low e glass


The following solution can be used to remove staining caused by contact with metal objects –

  • 99:1 Water and hydrochoric acid (for safety, ensure you add acid to water and not the other way round)
  1. Wet lint free cloth with some of the acid solution
  2. Gently try to rub the stain out

44 Responses

  1. Hi – have just installed $25k worth of windows and doors all with eVantage low e glass by Viridian and we absolutely hate it!
    Any tips on how or if it can be dissolved/taken off ? It looks grimy and and is so reflective we can’t we the views outside properly. Terrible product.

    1. You won’t be able to remove it because the Low-E coating is fused / laminated onto the glass during the manufacturing process. Unfortunately, you’ll have to either live with it or get them replaced entirely. The grime can be taken off using some acetone and a lint free cloth.

      1. Hi, I have cleaned these windows before many times and have noticed sometimes the outside is the rough side and sometimes the inside is rough. I have had success with a soft rubber on my squeegee using lite soap and lots of water with no problems at all. Is this normal? Did I get lucky on how I do it with light pressure with straight pulls only? These were on loE 272. The loE 366 windows seemed even more rough, is that normal? Thank you so much for this info, now I have the info I need to do these jobs.

        I’m still curious about the squeegee thou. It worked on the 272. Or did it???? It looked great when done.

  2. Hi, same issue as Jane we have the E glass windows installed.
    We had them cleaned post build which has left all types of marks and scratches on them. I’m now looking for a business who understands the cleaning process and can get them looking new!
    I’m located in Melbourne and was wondering if Simpo Cleaning was also in Melbourne or know of a business that could assist. Thank you

    1. At the moment we only serve the Sydney Area.

      You should speak with the cleaning company which caused the damage as it’s their responsibility to fix an issue which they caused and a homeowner who paid for a service shouldn’t have to waste their own time worrying about it.

      Light marks can be removed using a cotton terry cloth (no lint) with 1 part hydrochloric acid to 99 parts water solution, be careful as you don’t want to get any of the solution on the frame and seals. Also remember to add acid to water and not the other way round (it releases a lot of heat)

      More than likely the windows are already damaged beyond repair if the cleaners used any sort of blade or squeegee on them (the coating is very sensitive and can be damaged by the slightest contact with metal objects). The cleaning company should pay for a replacement if this is the case.
      Traditional windows can be repaired using an abrasive paste and polisher, unfortunately, you can’t do this with Low E.

  3. I use spiff towels on my glass. Can this be used low e glass. No chemicals, just water and the lint free towel.not familiar with Spiff, it’s on the internet but I can’t find any info on using spiff on e glass

  4. We have low e glass and it doesn’t come up clean! We can see the round suction marks from the manufacturing process and there are now streaks where kids have run their fingers in the condensation. Any tips? Is it just something we have to live with?

    1. Hi Camelia,
      I think what you mean is that there are stains caused by the suction cups which were used during the window installation process (not manufacturing). This is something we encounter from time to time during after construction cleaning and we’ve had success removing it with a little acetone on a soft lint free cloth.

      You can try 99:1 Water and hydrochoric acid if acetone doesn’t remove it.
      Not sure how long you’ve had the windows installed, but you should bring it up with the builder if the marks don’t come off after cleaning as they are usually considered a defect (this is because low e glass manufacturers don’t recommend the use of suction cups during installation unless no other option is available since it’s possible that the suction cups can cause irreversible damage to the coating of the glass, especially if they haven’t been cleaned with denatured alcohol beforehand).

      In regards to the streaks, you can just clean these off with acetone or denatured alcohol. Use 10 parts water to 1 part vinegar to clean and maintain it on a weekly basis. NEVER use regular commercial window cleaning products like blue windex or ammonia to clean low E glass as these can damage the coating.

      By the way, I can see that you are from St Malo Bakery by your email, Just want to say that I tried some of your bread and pastry from a small stand in Bondi Junction and they tasted marvelous!! 🙂

  5. HI Simpo

    We are a cleaning company based in South-Africa and the Low E windows are introduced here. We have received a contract to do a builders however some idiot applied BOX tape to the inside of the window directly on the Low E glass and decided to pull it off leaving the adhesive side on the Low E for us to clean . Any advice for removing the adhesive (glue)


    1. Hi Wynand,

      We come across this almost on a daily basis as we get a lot of work from builders. Acetone is the best remedy for it. Just apply a bit on a lint free cloth and it should start to come off. Also works for removing silicone residue.
      This will mean the job will also take a lot longer (depending on how much adhesive is left on the glass) so you need to charge accordingly.

  6. Thank you, thank you. I was ready to pay to have my very large mirrors cleaned. But, instead, I tried your method even the water and vinegar solution. I will never buy the blue stuff again. My husband even noticed how shiny and streak free my mirrors were.

  7. I am getting black marks which won’t come off (kind of looks like charcoal stains) on my low e glass.
    Any idea what could be causing this and if it can be removed?

    1. Black stains on low e glass can be caused by contact with any sort of metal (eg. the use of metal scourers, kids resting metal objects on glass etc). We’ve had success removing these marks by using a 100:1 water to hydrochloric acid solution and a lint free cloth.

  8. Hello Simpo,
    I have a similar problem to Wynand. I am also a South African window cleaning company. we clean houses that have many square meters of e glass, am I correct in understanding that we cannot use a squggee on this glass.
    I also believe that some of the window installers, install the glass facing either interior or exterior direction, I have found that some of the glass feels rough on the one side and smoother on the other side, does this indicate which side the oxide coating has been applied, and which side should face exterior? According to some articles I have read, the glass should have the characteristic’s of Pinkleton glass, which indicates a specific facing side to interior and exterior.
    Your help is much appreciated.

    1. The side with the low e coating will feel rough (this is usually facing inside) and this is the side you will need to be careful with. The side WITHOUT the oxide coating can be cleaned as normal with a squeegee. The side with the coating can be cleaned with a lint free cloth and stains can be removed with the help of a little acetone.

  9. Hi

    Thank you for the messages, all so useful.

    I have low e glass. in the process of repairing my thatch roof, splashes of rubberized bitumen landed on the outside of the glass. My glass is installed correctly with the low e on the inside. How can I clean these black spots off the glass.

    1. You can use some turps to remove the bitumen from the glass. Should come off quite easily. Just rinse off well with some water afterwards. 🙂

  10. Hi,

    Great informative thread going here, however I have one issue that has not been covered but hoping there’s an easy solution, similar to the above.

    New house, all windows contain Low E glass. The painter did not mask any windows prior to using a spray gun to paint the ceiling, now I have been left with white overspray on every window. Please advise if any of your previously mentioned methods is suitable for paint splatter on the interior Low E film.

    Any assistance is greatly appreciated.


  11. Hi there Thank you for your posts to help with low e glass! We have low e glass and fine overspray from the painters – latex paint. I tried vinegar and water but no luck. What do I do?

    1. You can use a little bit of methylated spirits or mineral turps with a cloth to soften the latex paint and then buff it off with a seperate dry cloth. Should come right off. Make sure – NO BLADES OR METAL SCRAPERS!

    2. So, I think we have the low e windows in the house we moved into last April. It has metallic reddish dots multiplying, I believe between the two panes, particularly on our sun-ward windows. Is that normal? Is there any way for us to clean those? What is it anyway?

      1. I would try cleaning it first with some acetone to see if it comes off or gets lighter (if this happens, it means its on the surface of the glass and it can come off). If it doesn’t get lighter then it means the glass has a manufacturers defect and you will need to contact the glass manufacturer to see if they will honor the warranty. The spots are caused by condensation / moisture getting into the 2 panes of glass and cannot be cleaned as it is a defect caused by the seals or contamination during manufacturing.

  12. Hi
    We have installed low e glass and noticed a paint overspray in the middle of one of our doors.
    What is the best way to remove the paint?
    Its about the size of a tennis ball
    Thank you

    1. Use some mineral turpentine for it. Apply with a clean cloth which will soften the paint and it can then be buffed off with a clean towel.

  13. Hi Simpo, your advice please. From South Africa. A home owner had low e glass installed in sliding doors and cleaned the glass with some type of chemical. The result is that now her glass is covered in black streaks. It looks like the chemical reacted with the coating, softening the surface and the streaks are the result of this as she wiped the window. Can these streaks be removed. If so, please advise as to the process to follow. Your input would be highly appreciated


    1. Hi Donovan, you can usually remove these marks with some acetone. Be sure that you tell your client that they CANNOT use coloured cleaning chemicals to clean the low E glass coating as they can react with it.

  14. We recently installed large 3 metre high sliding low E glass doors and windows in our new renovation in Adelaide.
    Low E glass may have some benefits, but in our opinion, the disadvantages outweigh them. Apparently this glass is now commonly used in new homes and renovations and (for certain West facing windows with high heat load), building regulations stipulate it’s installation as mandatory.
    We don’t like the maintenance problems of low E glass, and the slightly smokey appearance it has when exposed to direct sunlight, ruins the clarity of the view and is annoying. Had we been advised of these problems prior to the window order being placed, we would never have agreed to it being used.
    Unfortunately we were never told about this glass and it’s susceptibility to damage when cleaning. As a result we permanently damaged the expensive glass sliding doors by trying to remove paint spots the builders painters had left behind, with a razor blade.
    We became aware only after we engaged a professional window cleaner to try and fix the problem we created with incorrect cleaning. They explained the low E glass product and the care needed when cleaning.
    When we spoke to our builder, he was surprised and said he was completely unaware of the problems with low E glass.
    We would never recommend this product and would advise anyone building, or renovating, to consider other options.

  15. Hi Simpo
    We had a blue protection film placed on our inside windows during a new build. We now have streak marks All over our windows .These marks only show up with condensation, temperature change and when the sun reflect.
    Could this come from the protection film or could it be a fault in the glass?
    Thanks for your help

    1. Mainly two reasons – the first is because the low-E coating is highly reactive to metal (causes black marks) which makes the squeegee with brass or metal handles unsuitable. Secondly, even if you were able to find a squeegee without metal components, it still wouldn’t do a good job cleaning the low-E glass surface since the coating is not an entirely smooth surface (a squeegee is only effective when used on a completely smooth surface).

  16. We have Low E glass and have experienced many of the problems noted – mostly because builders/painters/window filmers have no idea what it is – they all vehemently denied they marked the glass. I have used a 10 cm wide painter’s razor blade to get rid of paint spots but only keeping it very well lubricated and applying no pressure at all – just the weight of the blade on the wet glass. It’s very easy to catch the corner of the blade and leave the tell tale metallic streak and then you need the acid dilution.

    My question is what can be done about scratches on the interior Low E side? Can they be polished out like normal glass. I don’t care about removing the E coating if it means getting the scratches out.



  17. Hi
    Can you clean low e glass with WD40 on the coated side.
    I have really baked in masking tape on the low E windows.

    1. We use acetone or a product called goof-off to remove masking tape residue on low-e glass. I wouldn’t use WD-40, since it’s not a product recommended by any of the low-e glass manufacturers. Keep in mind also, that Low-e glass manufacturers don’t recommend using any masking tape on the internal surface because there is a risk that it leaves residue which cannot be removed (regardless of the cleaning product used)

  18. We are currently in the process of doing a knock down rebuild and have installed low E glass windows in the new house. The some of the windows have concrete splatter on them, some on the inside of the windows and some on the outside, what is the best way to remove the concrete without damaging the windows?

    1. The concrete on the outside can be removed with the help of products such as crete-off or liquid hammer – be careful with these products, as incorrect application may cause damage other parts of the windows (such as the timber frames). In regards to the concrete on the inside of the windows – there is currently no recommended cleaning products or processes for cleaning this off and this is the reason it is crucial for builders and contractors to protect the internal window glass during the building process (not doing so will automatically void the warranty for the glass). We’ve had varying levels of success removing concrete off the internal of low-e glass windows by using a 99:1 Water and hydrochoric acid solution.

  19. Hi, I have noticed mould on the inside of my bedroom e glass windows. I think it might be because I have a heater in my bedroom during winter and I get condensation. What should I use to clean it off?

  20. Hi
    I have read the this thread and have become very educated on low e glass after the fact. ?
    Your information is so helpful. But I may be doomed.
    I think I have some scratches! So in your ad above with the sample scratches, read to use 99:1 hydrochloric acid and water, Is that right?
    Also where do I buy hydrochloric acid?
    Thank you so much for the information and you time

    1. Hi
      This Nikki
      I sent a question in above and have not heard?
      Just wondering if you received?
      Waiting fir your reply.

  21. Is there any way to eliminate the Low-E coating completely? working on an assignment on reusing/recycling the glass from the deconstruction buildings.

  22. I haven’t got e glass and after reading all the problems people have with it I’ll be sticking with what l’ve got. You certainly sound like experts, thank you for sharing your knowledge.

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