Good News! New Types of Low-e YOU NEED TO KNOW THIS


Please read the first post, there is new info on this.


It might as well be a low-e coating though since you are restricted in the same way w/ the self cleaning coating and low-e. No real difference when it comes to cleaning and the hassle.


I plan to avoid these windows with coatings on the exterior where window cleaners will contact them. Are the worst offenders currently Anderson and Oldcastle? Any other manufacturers that anyone is aware of?


I meant to say either side that we clean (the indoor and outdoor side).


Worst offenders?
Please forgive me if I’m way off base here, but are you actually a window cleaner or someone paid to write forum submissions for SEO?

If you are really a window cleaner, please forgive the above statement.

Almost all glass manufacturing companies now have self cleaning glass. I wouldn’t consider them “offenders” really, I’d actually call them innovators. Each manufacturing company has its own instructions for installation, CCU, and mainting the windows with usually detailed instructions on how to clean their product without voiding their warranty.

Many have actually stated on the label that the only recommended method is with purified water and a clean, very soft bristled brush.

This being said; when in doubt, call them and ask. It don’t make you less professional to do so or to not really know something. On the contrary; if you don’t know, admit it and make it your job to know, REALLY know. This is the difference between a bucket bob and a professional.

Hope that clears it up for you, and if you are an “SEO” guy, please at least take the time to be able to contribute value. No offense is intended, again.


I’m new to window cleaning and I don’t want to scratch the windows. I thought low e would be in between the panes. If it is on the surface I want to know how to identify it so I don’t scratch it. It sounds like Anderson and Oldcastle are the main manufacturers making them this way. I wanted to ask what other manufacturers are putting on low e or other coatings on the surface as well. I am on this forum to learn what I can before I find things out the hard way.


Best advice i can give you is to use the search option here and start reading and learn.

Here’s a link to get you started.

Research is your friend!

Hope this helps.


Cool. Sorry for judging man. Sometimes we get spammers.

I think the title of my post years ago was inaccurate, I tried to update the post underneath it to reflect that.

Its not low-e coating on the glass on the exteriors at all, but a different type of coating (titanium oxide).

And just about every major manufacturer around now has it. The post was 5 years ago, and the only thing I knew about this stuff was reading about it and it was for commercial high rise buildings at the time, new ones.

So on the residential level I never thought I’d run into it.

The messed up thing about it is you won’t know about the coating unless the sticker is still on it or someone tells you its there.

This particulat homeowner knew what she had, because I’m sure it cost a pretty penny and she didn’t want to void the warranty on it so she was trying to be sure I knew how to clean that glass (when in fact I didn’t know at all how to clean it).

So, what I do now is I will ask them if the windows are old or new. I tried asking what type of glass the windows were but it was too confusing and just didn’t work and made myself look extremely stupid.

If the windows are new I will ask if they are any type of special glass that they know of.

This will clear you if in fact it is self cleaning glass and you screw it all up.

Hope that helps and again sorry for thinking you were a spammer. My bad.


Got it. Ya I’ll be asking the owners for sure. I’m still reading up on the titanium oxide and any other surface coatings that I might contact. With the titanium oxide I need to ask around the forum if you can feel any drag? I think I have seen posts where people are saying that when you squeegee it it drags or something. Good info, WCR has a ton of knowledge and experience.


So true, if people looking for information use the search option they would find tons and tons of great information at the tips of there finger.


I came across glass in high-end residential with a coating on surface 4 (inside).
Right now cleaning windows from Quantum that have this issue.
Squeegee doesn’t slide, sort of drags and you cannot touch it with metal - no steel wool, no blade OR you will be leaving a faded Sharpie looking mark.
I ended up using a synthetic white pad and a spray bottle with denatured alcohol to remove silicone smears, sticker residue, etc. I then cleaned traditionally with soap and squeegee. It does take a lot longer than cleaning with steel wool.
I am doing a CCU with this issue on surface 4, some windows and doors already have damage (black marks) and I was wondering if those marks are permanent or can be removed with something.


From what I have read a mild hydrochloric acid mix mill remove these black marks, I have never personally tried.
ComfortPlusCleaning.pdf (48.1 KB)


If they are black marks from scrapers or steel wool it can’t be removed.


I remember reading that barkeeper’s friend or another mildly abrasive cleaning solution can help with those marks.

It sounds like you’re dealing with a hard coat low-e coating, which is harder than steel and will actually abrade any metal that it comes in contact with. The barkeeper’s friend should remove the traces of metal that are left on the surface.


I just told you how to remove them, and linked the product info…

Barkeeper friend is an abrasive, I would think it would scuff the low e surface.

Remember Down here we do not IG units thus we never have the luxury of not dealing with the low e surface.

I suggest you follow the manufacturers instructions, comfort plus is the brand of low e coat here, find the correct instructions for the brand you are dealing with, I think you will find the cleaning instructions will be the same.


I tried Bar Keeper’s Friend today on those black spots, successfully!
The active ingredient is oxalic acid .
I didn’t try hydrochloric acid since Bar Keeper’s worked.
I use ACE Hardware toilet cleaner for hard water spots removal (hydrochloric acid), but that stuff is nasty smelling and I didn’t even try it since Bar Keeper’s worked.
Thank you guys for recommending Bar Keeper’s Friend, it saved me a lot of time.


Ya link doesn’t work


Its a PDF that downloads to your computer.


As a disclaimer, this is my first official post here, but a long time ago, in a site far far away, I wrote the original “cut and paste” that Thor posted to open this thread, I am not sure if that should count as my first post or not. :sunglasses:

Anyway, to be honest I found this site/thread entirely by accident while looking for something else at the time, but when I started reading I realized the original cut and paste was mine. And while I enjoyed reading the entire thread, I did notice a few misunderstandings or discrepancies that I could address in the hope that someone may find my comments helpful.

I wouldn’t have reopened a 6 year old thread, but since there were entries up to late 2017 there does appear to be some interest in keeping it alive at some level.

Okay and to start, there are glass companies and there are window companies. Glass companies don’t make windows and window companies don’t make glass. Andersen and Old Castle were mentioned several times in comparison, but that really isn’t accurate because Andersen is a window company and Old Castle is a glass company (among a few other things).

The primary residential glass companies in North America are Cardinal, Guardian, Pilkington, PPG. Note I didn’t mention Old Castle? they are a glass fabrication company, meaning they do stuff with glass that they buy from one of the actual glass companies, but don’t actually make glass.

The others I mentioned all make glass from sand and other stuff. Cardinal is by far the largest contributor to the residential window market. They make the glass and sell it to window companies, but they also coat it (about 70% of residential coatings come from Cardinal), temper it, laminate it, and make it into dual pane or Insulating Glass Units for a crap-load of window companies.

In the residential world, the distinction between window manufacturer and glass manufacturer is fairly well defined, but in the commercial world its a bit fuzzier. But that’s just details. A great many window companies (especially smaller ones, but a few big ones as well) buy glass and make their own IGU’s. No window company coats their own glass, but many temper glass and a handful laminate their own glass as well.

As mentioned in the first post there are two versions of LowE coatings - hard coat and soft coat.

It’s common knowledge among glass professionals that hard coats can be exposed and soft coats must be protected either between the lites of and IG unit, or else inside a laminated unit. You cannot expose a soft coat LowE coating or it is going to be destroyed, and once upon a time it was that simple…however…not everything is as it seems (sometimes).

Hard coat = pyrolytic (or vapor deposition), meaning “exposed as a fog and then cooked on to the glass surface while the glass is still molten in the float process”. Typically Florinated Tin Oxide, often with other junk added.

Soft coat = Magnetron Sputter Vacuum Deposition (MSVD), meaning finished glass pushed through a series of vacuum chambers filled with various gasses and plasma’s where the metals and metallic oxides of the coating are applied atom by atom. Usually silver being the operative ingredient, but could also be stainless steel, or titanium, or even gold for some specialized applications.

Simple stuff, right?

Okay, so when talking about surface 1 or 4 coatings it used to be all about the above, hard coat typically 1&4 while soft coat 2&3, but then Cardinal Glass (the 800lb gorilla of the residential glass world) developed sputter coatings that could be applied to surface 1 and 4. Specifically NEAT for surface 1, which is Cardinal’s version of the “easy clean” coating, and I89 which is a surface 4 coating developed to improve U-value of glass.

So while these new coatings were technically soft coats, based on the Magnetron Sputter Vacuum Deposition (MSVD) definition, they were developed to be on the exterior surfaces of the glass.

So when talking about Andersen, Marvin, Pella, plus the majority of the next few hundred of the biggest window companies, you are talking about Cardinal Glass and you are talking about I89 and NEAT exterior coatings.

oh and as an aside “Please note, the source of this information does not come from an official or trusted source.” from the original post. I am not official of course, but I like to consider myself reasonably trustworthy.

okay back to it.

Andersen’s LoE4 did not mean four coatings. In fact AW LoE4 had two coatings - an actual low emissivity coating between the lites of the IGU - typically Cardinal LoE²-272 or LoE³-366. The second coating was NEAT on surface 1. The other two items on the “4” of LoE4 were argon gas between the lites to improve U value and the plastic film placed on the glass at the Cardinal factory to protect the glass during manufacture and shipping and installation - called Preserve.

When cleaning glass, you CANNOT damage the LoE coatings between the lites of the IGU, but you CAN damage the coatings that are on the surface of the glass.

If in doubt over how to clean them ASK!! As was pointed out by other posters.

So a few lines back I called NEAT as “easy clean” coating and not self-cleaning. That wasnt an accident. Cardinal has never considered NEAT to be 'self-cleaning". They always considered it as easier to clean glass.

As pointed out in other posts, the surface 1 coating is primarily titanium dioxide. Cardinal applies it as a sputter coating while Pilkington, Guardian, other glass companies, apply it as a pyrolytic. Pilkington (among others) refers to the coating as self-cleaning, but that can be misleading. And btw, the sputter version is much smoother at a microscopic level versus the pyrolytic version.

In order for the coating to “clean the glass” it needs direct UV exposure and it needs water, be it rain (self cleaning) or a garden hose (easy cleaning). AND it is not impossible that it might need a cleaning solution and a squeegee on occasion when it’s really dirty.

The coatings need UV to oxidize organics, basically cooks the dirt (called Photo Catalytic Oxidation - memorize that one and mention it to your clients when you are quoting a job. That’s gotta add a couple bucks per window just because it sounds so cool!).

So what about inorganics? The coating does make the glass "slippery’ (think of it kinda like teflon in a pan, but not exactly that) so its “easier clean” for someone cleaning the window to remove the inorganics versus ordinary glass. But once again, FOLLOW DIRECTIONS!

Once the UV has finished Photo Catalytic Oxidationzing the organics you spray it with water and wooooosh all the dirt rinses off and the glass dries clean. But why?

Ever use RainX? RainX brags that it makes glass bead up on a surface, and it does that really well because RainX is hydrophobic, meaning it repels water. Beads are cool, water beads on glass or on your new paint job are cool too, until the water evaporates and leaves all sorts of minerals behind. Be it the glasses in your dishwasher, your car’s windshield, that window that you just cleaned to crystal clarity before it rained…water spots, and the homeowner or building manager is asking you what YOU did wrong.

The surface 1 coatings are hydrophilic, meaning they like water, they don’t repel it. Water spreads out on a hydrophilic surface because of low surface energy. so it sheets taking all those water-spot-causing-minerals along with it. Including the organics that the coating previously oxidized. Clean glass, no water spots when it rains right after you finished cleaning the glass to crystal clarity. Happy homeowner, happy you.

And btw what if the glass surface doesn’t receive enough UV light from the sun for the Photo Catalytic Oxidation to take place? Shade tree, wrong exposure, shadows from the neighbor’s house, whatever blocks the UV from reaching the glass. Well in that case there ain’t no Photo Catalytic Oxidationizing happening so the coating isn’t cooking organics and those uncooked organics ain’t rinsing off the glass when it rains. Get the picture? Glass needs cleaning the old fashioned way…BUT it’s still slippery and water is still going to sheet, so it’s still EASY to clean…but FOLLOW DIRECTIONS and you are looking to save time and energy and have a very happy homeowner if you do it right.

This glass isn’t going to replace window cleaners, but it may help a professional clean more windows in less time, if you do it right.

Glass companies and window companies are your friends…they want happy homeowners as much as you do. If you have questions ASK THEM, make a phone call. I promise you that the guy or gal you talk with at the glass or window company wants you to succeed, because when you do it’s a win for them too. Trust me on that one!!

and sorry for the typos and rambles…


Thank you for the additional info man. Who are you? You obviously know what you’re talking about, personally speaking I’d love to hear your input on this forum. That was a really good read man.

Well, I hope you stick around…you already got my respect…

Welcome by the way