Many manufacturers are shying away from 181 glass due to it's low condensation resistance.

Do you mean i81? I don't think 181 is a Cardinal product. I suspect there's no such thing as i80 either, but haven't been able to confirm or deny it.

Hopefully oberon will make an appearance and set us all straight!

i81 is a hard coat low-e that is cast into what is surface #4 (the inside surface of glass facing the home). It does provide for better thermal values with minimal offsets in SGHC, however, as Eco mentioned, it can have sweating issues because is lowers the condensation resistance (CR) of the total unit to the low 50's in most cases. That is not a suitable number in my opinion and especially if you live somewhere with high humidity like Seattle.

Low-e 180 is a soft coat Low-e with a mid-high range SHGC.

It is well suited for the South facing windows if you are trying to maximize passive solar, that is one of the preferred coatings.

Yes, that matches what I've read on the Cardinal web site, and in the informative postings here. The question is, what is this so-called "i80"? Is it really another name for LoE-180, or is Comfort Design just confused? I'm leaning toward the latter explanation.

And is there any basis for them claiming LoE-180 is a new and relatively untested coating? I find that hard to believe, as it superseded LoE-179, which superseded LoE-178...

Any tips on cutting through the red tape with the window mfgs? Will companies like Simonton and Comfort Design talk with homeowners?

180 is not a very common option, however "untested" really doesn't hold any water.
Some window manufacturers are fairly friendly toward consumers, others prefer that you deal with your dealer... A phone call to find out certainly would not hurt.

1) "LoE-180 is the same thing as i80", which I find suspicious, as this sounds a lot like *i81* which is a different kind of coating altogether (pyro coating on surface 4, the indoors-facing "outside" of the IGU).

As has been thoroughly pointed out by previous posters (all very knowledgeable window professionals, btw), i81 and LoE-180 are not the same. But the terminology between those two products can be a bit confusing because the names are so darn similar.

However, both i81 and LoE-180 are sputter coats, neither is a pyrolytic. While LoE-180 can only be used inside of an IG, i81 can be used on an exposed surface because it doesn't use silver as part of the interlayer (no corrosion issues) and because it is physically much more durable than a standard LoE softcoat.

2) "LoE-180 / i80 is a new product" and they aren't comfortable warrantying it. Pretty sure this is bs.

Pretty sure I agree with you.

3) I can only get this if I spring for tempered glass.

i81 is only available in either heat strengthened or tempered glass. LoE-180 doesn't need the glass to be heat strengthened or tempered (with the exception of certain tinted glass/LoE or triple pane applications - which I strongly suspect would not apply), so that isn't likely to be an issue either.

It really does sound like you are getting a bit of a run-around from a window rep (or two) who isn't quite up-to-speed on his products.

You may have seen this already since you have visited the Cardinal website, but if not there are three Cardinal plants located within a short drive south of Seattle.

Cardinal has a float line (where glass is manufactered) in Winlock, a coating plant in Tumwater, and a tempering plant in Chehalis....

guardian has a similar product,

Oberon,

Copied from your post........
However, both i81 and LoE-180 are sputter coats, neither is a pyrolytic. While LoE-180 can only be used inside of an IG, i81 can be used on an exposed surface because it doesn't use silver as part of the interlayer (no corrosion issues) and because it is physically much more durable than a standard LoE softcoat.

I did not know that. Thanks for clearing that up.

Does this same soft-coat low-e does drop the CR number a bit further though?

Guardians version is touted as a hybrid but it does bring the CR down. i beleive Cardinals does as well.
both wont scratch and wont cause the window to become " hazy" as hard coats would on surface 4.

I'm quite familiar with both products. i81 (or i89) is a durable Indium Tin Oxide coating. Although it is sputtered onto glass, it is for all practical purposes a hard coat (it's a metal oxide, not a silver-based soft coat). i81/i89 can be placed on exposed surfaces (typically, the glass surface facing a room)

LoE 180 is a Cardinal conventional softcoat configured for high solar heat gain. Like all softcoats, it must be located within the insulating glass, because it will corrode if left exposed.

Both are high solar gain coatings. I believe the condensation concerns regarding room-side hard coats to be over blown (I've tested performance side by side), but it sounds like you want LoE 180...it's cheaper than i81/i89. BTW, there is no such thing as i80...as you suspected, your source is confusion the two coatings

Trapper,

It is good to have another intelligent window pro posting on the site.

Thanks for your input.

Why do you think the CR drop is overblown? The CR number takes a significant hit with room side Low-e coatings. If you compare the same window with a standard soft-coat vs. the soft-coat/hard-coat combo, the CR number drops by 10 points to the low 50s and is only slightly better than the clear, non-argon filled option (in this case that number for the clear glass option is 45, the combo low-e is 50, and the standard double pane insulated is 60).

If a customer has experience a window that has sweat previously, a hard coat low-e combo might keep that surface temperature just close enough to the dew point to still sweat.

Go ahead and charge a customer for new windows that still sweat and see how they react. You will have your hands full for certain.

Most of the people that we see selling this combo (we offer it as well) are not discussing this potential. We do offer but we require the customer sign and acknowledgement of this potential and that it is not a malfunction of the window at that point.

windowswashington,

The CR number is an abstraction and as such runs the risk of not correlating (to a greater or lesser extent) with the real world. It's probably better to look at the thermal simulations and the predicted surface temperature directly. Side 4 (roomside glass surface) loE coatings reduce the glass temp by 10 degrees in the cold condition simulations at the center of glass. Pretty significant. However, the delta is much less around the perimter of the glass, where the condensation potential is at its greatest due to other effects (sash thermal insulation effects, IG spacer thermal condition, etc.)

I've tested side 4 low-e/no side 4 low-e products side by side in various temperature and humidity conditions (in a lab), and found the condensation differences much much less that one would gather from the CR ratings. Basically, condensation bands start at about the same point, and the ones on the side 4 low-e product get a bit bigger, but I personally find the difference pretty minor.

And just to add a comment to what I just wrote...I think the condensation difference associated with stainless IG spacers in comparison with aluminum IG spacers are are much greater driver with respect to condensation than no side 4 low-e coating vs a side 4 low-e coating.

Glass bite (how deeply the IG spacer is buried in the sash) is also important.

I would agree with you that the differences are probably slight and that an aluminum spacer vs. warm edge would have a far greater detrimental impact.

That all being said, if you have a customer that likes to run a humidifier in the winter and has grids on their windows, try explaining that to them when their window sweats at the spacer and at the grids.

While the spacer section of the IGU is going to be more thermally bridged to the exterior, the offset in glass temperature with the surface 4 coating will also allow that spacer location to be even colder and more prone to dewpoint (assuming we are in the heating season) than normal.

We do see some customers that keep their RH way to high and dewpoint can be quite close.

Even your warm edge systems will be near 40 degrees (and below) with the temps that you get in the upper half of the United States. At that point with only a RH of only 40, dewpoint is at 43 degrees. If the non surface 4 Low-e kept it at 50 degrees, that window will be far less likely to sweat than a 40 degree edge of glass

At the end of the day, we offer it but we do disclose to customers the potential drawback with the lower CR numbers.

windowsonwashington,

Yes, you are correct...at the edge of the glass, it would even be colder with a side 4 low-e coating...it's just less than the COG 10 degree delta that (I suspect) drives the poor CR number. Based upon my testing experience, the CR number unfairly penalized the side 4 low-e coating. I've been involved in a fair bit of testing that has demonstrated this. My company also offers the coating and hasn't detected an uptick in complaints on these products (we've sold quite a few).

Trapper,

If the COG numbers are -10 in these applications, why wouldn't the glass edge show a similar drop?

I guess I can figure that the edge of glass temperature is already lower that perhaps the impact is somewhat mitigated, however, COG drop is pretty large and especially if you figure that is the most efficient portion of the window.

Condensation can be an issue even with windows with a high CR rating if the homeowner has window treatments that restrict internal airflow around the window or they set their humidistat on a high setting. Particularly when considering the slight difference in internal reflectance, I really don't see the benefit vs the potential moisture problems over Cardinal 272 glass.

I agree with WoW in that there's no way I would sell this to a consumer in my area of Northern Virginia without having them sign something acknowledging the condensation potential.

Windowsonwashington,

Essentially, the effects of the low-e glass coating are partially offset by the sash, which has a high emissivity surface that leads to more thermal radition absortion from the room. Net/net, side 4 low-e coatings have less of a temperture effect at the edge in comparison to COG...this is shown quite clearly in thermal simulations.

For those of you skeptical regarding the condensation potential of side 4 low-e coatings...I was there once too, but through testing demonstrated to myself that it wasn't a big deal. But don't take the word of anonymous poster...if you're in the window business you might want to run your own experiments in your own home or the homes of friends or family.

These coatings will become more common when the new Energy Star criteria are implemented in jan 2014...for many or most window products the only alternatives to satisfy the .27 u-value criterion in the north are significantly more expensive: triple IG or krypton gas.

Cheers!

Trapper,

I agree that the net effect of surface 4 Low-e on edge of glass temps will not be a linear relationship between the COG drop, however, even at a 50% translation, that drops that edge temp much closer and into those dew point numbers.

68 degree room temp with 40% RH = a 43 degree dew point. That is an easily achievable number with even a good double pane low-e, warm edge spacer equip window with cold outside temps.

WoW,

Don't disagree with anything you said, merely that in practice and testing, I haven't found that it has mattered much. In controlled testing, it was very difficult to get condensation to form on the side 4 Low-e product and not the non-side 4 low-e product. As we took exterior temperature down and interior humidity up, the consensation bands were somewhat larger on the side 4 product than than non side 4 low-e product, but not objectionally so (or, more accurately stated, the condesation on both products was equally objectionable). We did a lot of testing, because we were concerned about this initially.

But, as I stated in my last post, don't take my word for it ....I encourage that you try it yourself side by side in a home.

Thanks for the feedback. It is good to see another informed pro on the boards and I will certainly look forward to future discussion with you.

This is a great thread....

Trapper, welcome to the window forum and like WoW said, looking forward to some interesting discussions down the road.

I have a few questions if you don't mind...and since I am going to assume you tested i81 as surface 4 of an IG:

What coating was on surface 2 of the IG?

Did you test using both stainless and aluminum spacer? Any other spacer?

Were the IG's in a sash/frame for testing? If so, what material(s)?

And in the interests of keeping the thread going a bit longer, a few more comments...

Although i81/i89 is a "high solar gain" coating, that truly is not the intent of the product and I can't think of any IG application where it would make sense in that application.

By way of comparison, as a surface 3 coating in an IG with 1/8" glass and 1/2" airspace, 180 COG has a SHGC of .69 and U.27.

i81 in the same configuration, except surfce 4, would have a SHGC of .67 and U.36 - not bad numbers (and comparable to most pyrolytics), but not as good as LoE-180.

However, i81 in a monolithic application (as a storm window for example), will have a SHGC of .68 and U.63 - which once again rivals hardcoat performance without the clarity issues common with the pyrolytic process.

Oberon, answers to your questions:

1. we tested with LoE 366 on side 2. (we actually tested with Pilkington Energy Advantage (conventional pyrolytic) on side 4, but i81/89 should perform similarly).

2. testing was done with stainless steel IG spacers (Cardinal's, if I recall correctly).

3. The we tested the IG in wood clad casements and double hungs.

I agree with i81/i89 not really being the best choice as a high solar gain product. Same goes with Guardian's indium tin oxide coating. As you mentioned, single silver layer low-e(Cardinal LoE 180) or conventional pyrolytic would be much cheaper way to get the same effect (180 yielding a somewhat better effect). BTW, I have side 3 loE 180 in windows in a portion of my home that gets direct sunlight typically only in the winter.

Also BTW, with respect to pyrolytic clarity, you might want to check out the improvements Pilkington made to Energy Advantage a few years back. They pretty much completely resolved the haze.

Thanks! Look forward to talking to you and WoW in the future.

I've really enjoyed the educational comments in this thread. Thanks everyone!

An update on my high-SHGC quest: One of my bidders claims they can get LoE-180, no problem, but another says it is not available, from the same window company (Comfort Design). I called them up myself and after several back-and-forths was told "no, sorry, we don't offer that" so I think there was some mis-communication going on.

This puts me back to square one on high-SHGC glass. It looks like it just isn't available here, period. (Simonton also won't use it.) I may be forced to go with low SHGC and thus become part of the problem, instead of part of the solution. Man, that irks me. Most people in Seattle don't even have air conditioning! Is the whole industry nuts?

Anyone have other suggestions? Inside connections?

Thanks for the info Trapper. I agree that the haze issue in pyrolytics is much better than it used to be.

haunma,

The Cardinal plant that would be fabricating and supplying the LoE coated glass to the window company is probably less than an hour from you (depending exactly where you live of course).

If I were you I would call them on the phone, explain your dilemma, and ask them for information on local window companies that do offer LoE-180 as an option.

The coating plant is in Tumwater. You can get their number from the Cardinal website.

It seems I was overly pessimistic in my last post. After exchanging some email with the owner of a local window company (who also, BTW, was not conversant on high-SHGC options or why they would be desirable in a climate without air conditioning), I learned that they can special-order Cardinal LoE-180. No big deal (!)

It does seem that 90% of the battle here is education.

So now I have just one more small question: Seeing as how this is an unusual order for the window guys, is there *any* way for me to verify, by visual inspection or some other technique using household materials, that (a) the coating is actually 180 and not 272, and (b) the coating is properly applied on surface 3, not surface 2? If it helps, I will have other windows with LoE-272 which I could compare side by side.

Jeez, that's a tough one (I assumeyou don't trust the NFRC label). Off angle reflective color might work. 272 is purplish at the correct angle. I don't recall the color of 180, but it would be different, and possibly more muted. You might be able to pick up what side the coating is on via off-angle reflected color as well (I've never tried this, though).

You should feel the difference between 272 and 180 when putting your hand into a sunbeam that's passing through, as well (or perhaps put a therometer in front of each?).

If you trust the dealer so little that you think he would lie to you and try and rip you off, then you are not dealing with the right company.

You could use a heat lamp and a digital thermometer.

To the naked eye will be tough.

There should be a serial number on the window and you can contact the manufacturer or have the contractor submit the build sheet on the windows as well with redacted price information.

I am not sure what the contractor would benefit from by not putting it in there unless you were concerned about an error of ordering.

It's not the contractor I'm worried about--it's the window manufacturer. I'll send them a note to remind them that the LoE-180 goes on a different glass surface than the LoE-272, but it's obvious they haven't used this glass for a long time, maybe ever.

The windows will come with an NFRC sticker on them indicating the U-factor and SHGC. Should be easy to tell by that.

I wouldn't worry about Cardinal too much.

They are one of the elite glass makers.

Not worried about Cardinal either... I meant the window manufacturer (integrator?). The folks who buy glass from Cardinal and sell windows to contractors.

Haunma, how did your windows work out? Could you share who you bought them from? I'm in Seattle and just delving into the world of windows. It's complex!

I just ordered windows at Home Depot. I was surprised that I could specify LoE-180 in the Jeld-Wen 4500 line. Nobody understood why I wanted it, but it's there. Same price as Energy Star. Available with tempered glass and obscure glass also.

NFRC rated at U=.26, SHGC=.69

Great performance at a price 1/3 of what I was willing to pay for good south facing windows.

The glass may perform well but with Jeldwen that will be about it.......

Well my HD order order sheet reads LoE-180, but of course they arrived with standard LoE-270. A call to Jeld-Wen confirms "they've NEVER offered LoE-180".

So the runaround continues.

Ah the old HD shuffle. Like I have said previously box stores typically have no one in the millwork/window depts who know what they are really doing. I would hope there order sheets would be correct as the vendors should be helping them make them but again you never know.

I know this is a little strange but on the occasion that I am in HD or Lowes (only to buy exactly what I know I am getting before hand, lol) and I have a few extra minutes I like to go over to the millwork dept and make inquires about different products that I may be looking for for a HI project just to see how awful the the responses and while I cannot remember them all they are usually no even close to being correct or where to find the correct answers.

I like that one. You can I could go see that movie together. We would have the whole theater to ourselves.