Carova 2008,

I have read your post several times and I admit that I have several questions - most involving "why" - and the main one involiving "how much".

Obviously, it would be rude to even consider asking the "how much" question and I am in no way doing so, but I can't really see any window company agreeing to your requirements without flashing $$$$$$$ over and over; and then I am even more curious about how the original company, that is no longer in business, was planning to fulfill all of your requirements.

I am going to be totally (brutally) honest here and say that your requirements are such that I would have to agree with the Guardian folks that I can't see any window company that would want to work with you. Again, please understand that I am in no way criticizing your requirements - I am simply looking at them from the point-of-view of the window company - it is just that when you submit such specific requirements to the window company there will be people in the technical and quality areas of that window company that are going to see you as a potential long term "headache" for them. They are not going to be advocates for building these units for you.

Statements such as "...marginal index of refraction matching between the the plastic interlayer and the sandwiching lites (using a monochromatic light source at an angle showed strong reflections at each interface), terrible CRI (judged using Munsen Color chart)..." are going to be a HUGE red flag for pretty much any window company that I can think of.

And again, I am really curious how the original company was planning to meet your needs. I suspect that you should be gratefull that they went out of business BEFORE you gave them any money.

In all seriousness, I wish you the best and good luck with your search.

Hi oberon,

When we were working through the initial glass specifications, the window company (Benor) worked with us and Guardian (their architectural glass supplier) to design a glass system that meet all of our needs. Through the process, Guardian sent us samples, understood our issues (my wife is a visual artist, so the neutral color and high visual transmission were major issues), identified available glsss components in their standard line that could be used, and were able to assemble this into a reasonable cost (for us) package. For example, the laminated glass samples that Guardian provided had practically no relections at the interfaces (they were the ones who taught me the laser trick to judge the index of refraction matching). Yes, we are looking for a specialized requirement, but after dealing with Guardian I do know that it is possible. I am just trying to find a window company willing to do it.

Good morning Carova,

As I reread my original post, it sounded overly harsh to me. That was not intentional - although I did (and do) see it as reality. But no offense of any sort was intended.

I am curious about the involvement of Guardian directly in your research. That surprises me a little bit.

I am also curious about some of what they said and what they showed you re your performance requirements.

When Guardian showed you how to "see" the glass / interlayer interface did they explain why that was important to you in the final product?

What interlayer were they spec'ing for your application? PVB, SGP, PET, resin, are all possibilities. Depending on which interlayer they were showing you would depend differences on the incidence of refraction between the layers. And (as always) there are also potential differences in the overall performance of different interlayer products as well.

I am assuming that they recommended Performance Plus II LowE coating - possibly using their ultra-white glass for the substrate? "Regular" float glass has a greenish tint to it because of iron in the mix. Ultra clear glasses have low (or no) iron content so that they don't have the greenish tint of ordinary float glass. This gets you a higher VT when compared with other options.

And speaking of VT, they gave you the VT of the glass, but did they mention that when in a window system, VT is calculated using the entire window system and not just the glass? That can be misleading if you are not aware of it.

What spacer system did Benor spec for the IG construction? Was the IG a dual or triple and did they spec argon or krypton gas infill?

What was the overall width of the IG unit? I am thinking that they may have spec'd a narrow airspace (1/4" or so) IGU with a krypton gas fill? I am guessing this because laminated glass takes up a good bit of the space in an IG and the options are either increasing the depth of the entire sash/frame to accomodate the deeper IG (which may have been a product that they offered), or else they used krypton in a narrow space - where krypton does very well in energy performance).

Were the energy performance figures that they showed you for the glass package or for the completed window?

Since you were opting for vinyl, did Benor insulate their extrusions? By doing so, they could improve the energy performance of the sash / frame by a few percentage points.

Anyway, I am really just thinking outloud here. Kind of thinking what I would do if I were recommending for your requirements....

I am a bit curious if you have been in contact with any other window manufacturers, and if they have offered any encouragement?

Hi oberon!

I hope that you realize that part of my exasperation at this point was that Guardian showed us what was possible, and now we are just trying to achieve that goal. But on to your questions...

Guardian was the supplier to Benor well before we entered the process. When we went looking for windows and found Benor, and when our architect realized that the Guardian Architectural Division was willing to participate (there are some personal relationships involved here that made this happen), we started to get a tremendous amount of involvement by a couple of their engineers.

The Guardian folks were very helpful in explaining to me and my wife ALL the sources which would degrade both the VT and CRI, and then discussed all that they could do to reduce their impacts. One of the larger impacts on VT that could be mitigated was the interlayer index of refraction mismatch by supercritical choice of the laminate interlayer (including the batch number). They spent hours showing us more than two dozen samples, taught me the laser trick, and then explained why we would want to use their ultra-white glass with Saflex rather than some of the other PVB products available, and why the PET interlayer while it delivered better impact performance was not the right one for us. That decision alone they explained would improve our VT dramatically. They then introduced us to the Munsen Color chart as a way to assess color neutrality, and a myriad of other details that would appeal to the artist in my wife.

As we went through this process, they kept plugging the various lite selections into a program ("Windows 5.2") that predicted the performance of the whole glass assembly. Here is where I received the real education. What appeared to be relatively small changes in the components of the glass assembly (such as using the the ultra-white glass with Saflex) were responsible for increasing the VT by 5% (which I have come to find out is HUGE!)

The spacer that they suggested was a specialty, "two polymer, warm-edge" system that separated a dual pane glass system. The gap was was about 0.267" and filled with krypton.

No window glass on our house was wider than 32" (based on the advice of Guardian engineers).

After Guardian designed the complete glass assembly, Benor used that data to estimate "whole window" performance (including frames) and based on these data Benor suggested that they use a "fully foam insulated" vinyl sash and frame for our windows.

After this good experience, I had been very disappointed speaking with nearly all of the "established" window brands. Since then however, we have found a couple of specialty window makers that appear to be willing to work with us. The glass samples that they have sent us for inspection appear to be quite good and I am hoping that we end up with a positive outcome.

If anything, I think I am the product of "raised expectations" that were the result of a specialty window manufacturer who had tremendous pride in his work and a glass supplier who (for whatever reason) decided to show us the "bleeding edge" "art of the possible" for our house.

Personal relationships work. I agree with you that you got thru the door, at least in part, because someone talked to someone.

I would also bet that a good part of the Guardian engineers interest was because designing your window was fun for them.

I think that few people realize how tedious engineering can be at times and the challenge of pushing an established envelope, or perhaps trying to do something that no one else has done, is a great motivator for many engineers...in short, it is fun. It is why the engineers became engineers in the first place.

I am curious where you are building.

We have used our architect since she started as a one-person shop 25 years ago. She has since become very well known and has a company with somewhere over a 100 emplyees and no longer does private residences, but she did this one herself for us since we were one of her fisrt cusomers and have used her constantly over the years. Her projects are all large ones now, and they tend to use acres and acres of glass in very intriguing ways, and therefore knows a bunch of the folks at Guardian.

Yes, the engineers were having great fun showing us how they could "push the envelope" over what they did on normal days, and were particularly intrigued by the way my artist wife viewed something as simple as the color neutrality. I think that something was learned on both sides of the table through this interaction.

What I learned from this whole experience was just how much room there is for improving the quality of a product if there is a willingness/need and a desire. Would this have been immediately profitable for Guardian if we had purchased windows from Benor? I seriously doubt it. Will what they learned from the interaction show up in something that they do in the future? I would not be surprised. In fact, my wife has had continued contact with the engineering group soliciting her advice on some intriguing items.

The item at hand however is still the beach house that is under construction. It is being built in North Carolina, in one of the few unspoiled sections left on the beach. We are looking to have it LEED certified and still designed to withstand the top end of Category 4 with minimal damage. I hope we never have to test that limit however! ;)

Thanks for your help!

This discussion has been fun for me as well. Thanks

I think that you will find a company that can make your dream come true. It is just a matter of making them understand your needs. Don't be surprised or daunted if by any chance you happen to encounter any "attitude" - kind of like my first post felt. But in any event, just work thru it and get what you want!

Good luck and if you wouldn't mind you might drop a note here just to say how you are doing.

Hi oberon!

I have just spent an EXTREMELY frustrating month! I had no real idea what I had lost when Benor closed its doors, but even my worst fears did not leave me prepared for the reality I had to face. My wife is very unhappy and there is little I can do to make things better. The framing for the house is nearly complete and windows needed to be ordered, soon!

Almost without exception, I have found that manufacturers of impact-resistant vinyl windows that are rated by either Miami-Dade or the Texas Department of Insurance were either less than willing to provide the performance data on their windows, or had a "take it or leave it" attitude - here is what we make, order it if you want it - or both! The best results that we had was with a smaller company on the Gulf Coast, Shwinco. The engineer, Craig Shipp, was willing to work with us to get some semblance of what we thought we would be getting for the new house.

The final windows that I ordered this week have a DP of +/-65 and a reasonable SHGC, but at the cost of a VT that is 11% lower, a CRI 15 points lower, and a "U" 10 points higher than the windows that I had planned to get from Benor - and these were the best from any source. Most of the other manufacturers that did provide data were much worse than this! My wife is definitely distressed.

Perhaps I am mistaken, but I do believe that there is a potential market for higher quality impact-resistant lites in vinyl frames. Unfortunately, they are not there for our house.

I wish I could say that things turned out well, but as I said previously, we were the product of raised expectations that could not be fulfilled.

Hi Carova,

Darn. I was hoping that you would find someone who would take a chance and build what you were looking for. From your description it appears that the window company is ordering a fairly standard impact IG unit.

Again from your description, I would suspect that these windows don't have low iron glass, which would account for the VT and CRI changes.

I would also suspect that there really isn't much of a market for the window that you wanted. While in theory people would like such a window, few people would be willing to pay for it. Although there are some very nice, higher-end vinyl window systems on the market, most folks who are looking at high-end or ultra-high-end window systems are looking at wood windows rather than vinyl.

Your prerequisites tended to put you into a very limited niche market that few companies really wanted to explore.

To be honest, and as I said in the initial post, you would have likely "scared off" some folks when when you began talking to the window companies about Index of Refraction and asking about VT and possible color variations. Some of these factors can be difficult to control to the precision that you required (while staying within a realisitic cost), and I suspect that at least some of the window companies that you talked with simply didn't want to take the risk of attempting to produce windows that met your requirements for a limited (one order) return.

If I were in your shoes, I would consider myself lucky that the original window company folded before I had put any money with them. The fact that they were quite willing to make the window that you wanted (while apparently "stronger" companies are not willing or cannot do so), and that they went out-of-business, seems to tell a story all by itself.