Read this article.... Not flattering for window film.

Just thought you may want to be armed against the stuff being spread out there.

What Most Window Film Manufacturers Won't Tell You - And Why

so what is the mysterious spectrally selective window film has been installed successfully for years?

would love to post some sort of retort to that article.... Glare causing headaches. Heat, Visible light, and UV destroying everything in its path.

I don't think that guy did any real research on current films. He's using a 15% film as an example... really?!?! 15%.

There are many films that are much much lighter and block a good deal of heat.

The "Chief Engineer" got it wrong and is consequently spreading more of the dis-information he sought to clear up.

He uses the broad term "heat" without any appreciation for the fact that visible light (and light at any wavelength for that matter) is absorbed by everything within the building and re-radiated at longer wavelengths (heat). In other words, visible light is a significant contributor to heat. Reducing it to a moderate degree is both effective and desirable. They key is to find that "happy medium" but he offers no guidance on how to determine that.

Second. He has no appreciation or understanding of the physiology of the human eye pupil, which dilates and adjusts to the reduced light levels in less than two seconds. People wear RayBan Sunglasses (VLT=5%) every day and safely drive their cars at 70mph. Most pilots I know wear sunglasses when they fly. Does it "kill their view" and darken their morale?? Of course not. If the human eye pupil had a fixed aperture, his argument would hold water. It does not.

In 27 years, I have not heard of a single instance whereby anyone had to augment the artificial light as a result of the VLT reduction caused by film. Many offices are so overexposed to visible light that occupants have to squint to see their computer monitors and have to face their desks away from the windows to avoid squinting all day. In most cases, they wind up installing blinds that block almost all the visible light. It's the blinds (not the film) that cause the need to increase the lighting.

Does anyone have the name or contact info for "the Chief"?? I'll get him straightened out.

Howard Paritsky,
Express Films

Great post Howard!

Go on and get em

When you pull the feed info to post the article, like I did for the Linked In group, this is what comes up:

by: Marty Watts, President and CEO, V-Kool, Inc.

Now, I do not know that Mr. Watts wrote the article, but that information came from their website through the feed, so I am not making it up or trying to stir any trouble up. Can anyone that knows Mr. Watts confirm that he wrote this?

It would not surprise me if Mr. Watts authored it. It read like an endorsement of his products. Even if it was the President of V-Kool that wrote it, statements like that should not go unchallenged.

If someone can confirm it, I will take him on.

-Howard

dude, STICK TO SELLING TOOLS.
i've read this article when it fist came out. i've done many commercial rebate installation through out socal. this was done to sell spectra select films like vcool and HO.
dealing with facility engineer the first thing they look at is SHGC the lower the number the better. dealing with architects the who don't see utility bills want a less noticiable film.

DONT START CONTROVERCY AND THE MANU. AREN'T SPREADING IT AROUND!

now i know how you roll.

First, I am not trying to start anything or stir up any trouble. People asked who wrote it and I posted what I found. I even went as far as to say that I was not sure that Mr. Watts wrote it and asked if someone can confirm. By the way, I also know a bit about film as I still run National Glass Service Group and spent have spent nearly 10 years in this industry representing and selling films. As far as how I roll, I am just posting things that are out in the pubic domain. If Mr. Watts wrote the piece and people on here disagree with his assertions, he should defend the piece. Dont attack me for bringing to the forum what was published on a public website.

By the way, I was one of the few non-CPFilms employees that they authorized to give lunch and learn presentations to architects for AIA credit with their module, so I do know a bit about what architects and facility engineers want. Maybe you should do a bit of research on what my background is before posting about my credentials. But what does this dumb tool guy know anyway.

I want everyone on this forum to rate the article "not useful"

Why? Oh, I see. You meant on the site that the article is hosted on.

just called 2 friends(tint owners) in ohio. they said ........... about you.
your the guy who needs to sign a no compete contract before hiring.

out.

Funny. I can only guess which two guys that you called. That was a nice try to redirect this thread though. Now who is trying to stir up trouble?

Many seem to be finding this post useful, so I am not sure what your issue is?

TintStar:

For clarification - I completely agree with you. SHGC rules! If that's where you stand, the article contradicts you. Why the opposition???

People are entitled to their own opinions, but not their own facts. There are gross errors in that article. Why should they go uncorrected? It supports your position!

-Howard

That article has been around for quite a while, I've seen it before. Marty is taking a marketing angle for VK.



.SHGC is very important but it does not rule when your project has strict vlt transmission requirements such as when AP's go for LEED points in certain categories.

VC !!!! I was waiting for you to "weigh in" on this !!! Terrific !!!

First, can you confirm that "Marty" (I don't know him) authored the article and that he works for V-Kool?? It sounds like you know him.

Also: I now realize that you probably handle that product. Please address the following:

If I remember my meteorology studies (from my college days) infrared Light accounts for approximately 49% of the heating of the earth. The balance is caused by visible light that is absorbed then re-radiated at longer wavelengths. V-Kool emphasizes the fact that it does not block much visible light. How is this not a handicap? The visible light enters, is absorbed by the furnishings and the re-radiated at longer wavelengths (infrared).

In other words, IR blocking data addresses just under half the source of the heating. The balance comes in as visible (which the V-Kool proudly transmits) and is instantly converted to IR inside the building. Where is that quantified in their data?? Furthermore, I never see the bandwidth associated with the performance data. IR runs from 700nm well beyond 3,000nm. On the few occasions where I do see the bandwith disclosed, it's always within the 1,000nm range +/- 100nm. Since all manufacturers use different methods to measure it, how can consumers and installers rely upon it for comparitive analysis?

Is all this not the specific reason why the NFRC emphasizes the SHGC??? For the record, I totally agree with them. Do you oppose the NFRC's position on this??

Finally - Do you agree with the statement in the article that films in the 35%-50% VLT range are so dark that augmenting the lights is necessary?? I don't buy it.

Respectfully,

Howard

It sounds like we need a good old fashin debate. I vote for face 2 face one on one, in electric chairs. Someone lets say bends the facts or outright lies.......WHAM 50,000 volts. Someone boasts unproven data or skewed data......WHAM 50,000 volts! You get my idea. By the way the smart money is on HP

PJF, thank you for starting this thread. Howrd's articulation is great.

No thanks needed. That is what having a forum like this is all about. If this was written by Marty at VK, and he believes what was written, he should come on and defend his points. What concerned me about this article is that it is published on a public website that facility managers, bulding engineers, etc. may read. This piece can give them a completely inaccurate picture of what window film can do and cause some of these individuals to write off thinking about film entirely.

PWF >> I second that. If Marty wrote that, he needs to weigh in here.

A basic premise of his article is that anything other than a spectrally selective film will darken the windows to such a degree that augmenting the lights is not only necessary, but to such an extent that so much additional air conditioning is required that it results in a net energy loss. I find this to be preposterous.

I don't care for the title of the article, either. It insinuates that others are being deceptive or less than forthcoming. In regard to other manufacturers, he states that "they seldom confess that they also block visible light". Has anyone ever seen a data table that did not include the VLT? How did he come to that conclusion??

Furthermore, he states that non-spectrallly selective films will cause employees to "suffer more illness, take more sick days, be less productive and have lower morale". He should be sanctioned by that journal and a complete retraction should be published, forthwith.

Howard Paritsky
Express Films

I thought that was a bit odd as well, if for no other reason because you can visually look at the film pre or post installation and see how much light it does or doesn't allow through. It's not like that is a hidden feature of the film that you don't notice until it's too late.


-R

I got on the scale this morning to weigh in... it wasn't good.




Can't "confirn that" but I can tell you that the article is old. I do know Marty.



The 49% is up for debate but I believe to be in the neighborhood. Although it is energy, it does behave differently from the longer EM wavelengths in the NIR region. Visible light wavelengths reflect to varying degrees off of surfaces and that is how we see "color." V-Kool comes in varying VLT's the lighter ones are so because they design to film to be "spectrally selective" more so on the IR side which is only a handicap if you are going for maximum heat rejection bar none. If you have a storefront or similar situation then spectrally select is the way to go.



IR starts at 780nm I believe, but who is counting. It does run way out there but most agree that NIR ends at 2500nm. When IR transmission or rejection percentages are published, it is assumed that the whole NIR 780-2500nm is measured, otherwise you have to disclose what wavelength you are measuring. So VK's literature does not list a footnote like 3M so it must be assumed that they are measuring the entire NIR. If they weren't, the IR police would bring that to the attention of the community at large.

So to answer you energy question... the best way to cut to the chase is to compare .SHGC and for single pane you can even bring .SC into the mix. The high vlt spectral select films will only perform so well due to the fact that you mentioned and that is they are allowing more visible light to transmit.

Where the stacking technology behind these products shines is when you compare the LSG ratio. They are very efficient albeit not the highest energy rejectors because you can always reference a reflective 5%vlt film as having a lower .SHGC but the LSG is still not as good as these spectral select products.




The NFRC references VLT too, except they refer to it as "VT." I believe in total performance measurements, like SHGC, but at the same time I do not rely on it as the defacto say all in energy efficiency design. There are way too many other factors involved.





I don't agree with the way that article was written. There are some points in there but I believe they are way out of context. The statement about 35-50% vlt for instance, this can hold some weight in certain latitudes, climates, building orientations, and times of the year when foliage is thicker. Really it depends on a lot of different factors. I believe that natural light in acceptable levels is good for us in many respects, but the reality is that we work with programs that call for high light transmissions as well as energy control so we are called on at times to provide the proper solution for these situations. Low VLT films do not work in this particular context but they do work in others.

VC.

Nice job on the reply, but I can't let you off that easy. Your remarks are "underlined"

You state: "Although it is energy, it does behave differently from the longer EM wavelengths in the NIR region".

As you know, IR is the next longest wavelength. All of the visible light that V-Kool boasts about is re-emitted as IR. Unless you are suggesting that it's passing right by the IR band and being converted into microwaves, the visible light is heating that room up. There are no other possibilities.

We can agree on the storefront scenario - but that's as far as I'll go along. If a building owner calls in with a heat load complaint, high VLR films are far from the best choices, yet the SS V-Kool products are pitched all the time in these situations. Marty's article confirms this fact.

You state: So VK's literature does not list a footnote like 3M so it must be assumed that they are measuring the entire NIR. If they weren't, the IR police would bring that to the attention of the community at large.

That would be an incorrect assumption. Every single plot of IR rejection I have ever seen resembles a bell curve and each manufacturer publishes its data based upon the range where their rejection is highest, to the exclusion of all others. I have never seen IR performance constant throughout the range. It "ramps up" from the near visible, peaks around 1,000nm and then gradually falls off. I have never seen IR performance that resembled "a straight line". I guess you are going to have to show us your curves! I have no doubt that someone of your standing should be able to obtain that with a few mouse clicks.

"So to answer you energy question... the best way to cut to the chase is to compare .SHGC and for single pane you can even bring .SC into the mix."

Here again we agree, but that argues against ultra-expensive spectrally selective films for heat control applications.

"I believe in total performance measurements, like SHGC, but at the same time I do not rely on it as the defacto say all in energy efficiency design. There are way too many other factors involved."

Perhaps, but Marty's article and this entire thread is focused on IR. I think I have been able to demonstrate that the high VLR SS films are not good choices for IR applications. I often reccommend them for storefronts, however.

"There are some points in there but I believe they are way out of context"

You're being kind to a colleague. That's admirable. Still, he needs to check in here and set things straight.

Respectfully,

Howard

I appreciate the issue that you have with the article. First let me clarify something important. Marty is not an associate of mine, and if I come across as protecting his interests trust me, I am not. His company has sold around his customers in the past so I take issue with him in a totally different area.

The visible light transmission is a little more variable than NIR depending on conditions but despite that it is energy and the good news is that it is accounted for in the SHGC. So no matter what anyone says about it or what one film transmits and another does not, the energy resulting from it all is calculable and accounted for.

The IR curve looks like a stock gone bad, it is definitely not interpreted as a straight line even when film transmissions are measured. This is due to the varying intensity across the spectrum, it is not constant as you well know. The best illustration of IR transmission percentage calculation I've ever seen was done recently by CP Films tech dept. There is a way to get a calculation, it is a rather complex equation, but it does account for the entire NIR spectrum. I do not know if VK uses this same equation but I do know their R&D guys are some of the biggest brains in the business. The FIR is worthless to include because the materials in the IR films are not designed to filter those wavelengths. If full-range 780-2500nm reporting assumptions are not true in advertising then why does 3M, Nexfil, and half of Asia note the wavelength sampling of their IR measurements?

What I see day in and day out is movements. Lobbying can be found anywhere and everywhere for anything and everything. My issue is more with longevity rather than peak performance. I find this a much more interesting subject to discuss because I believe the implications are yet to be fully appreciated.

Good discussion today Howard.

VC,

We agree again. It's accounted for in the SHGC. That's where the focus should be if the objective is heat control, not the IR performance curve. I'll let the NFRC have the last word on it. I hope everyone that has read this thread has enhanced their understanding. If your customer has a heat load issue, focus on SHGC!

I take it you got your hands on the IR performance curves. As I explained, those are never level across the spectrum.

"If full-range 780-2500nm reporting assumptions are not true in advertising then why does 3M, Nexfil, and half of Asia note the wavelength sampling of their IR measurements?"

They should all publish their broad spectrum curves. I have seen most of the Asian curves and all the domestics that would share them with me. Any differences are nominal at best.

The only fair way to present it would be to publish everyone's curve and then to superimpose all the curves onto a single table for comparison. I hold little hope that all the manufacturers would disclose that. Those charging the most for their films stand to lose the most should it become clear that their performance was similar.

On the other hand, you can just throw all the curves in the wastebasket and focus on SHGC (as the NFRC does).

Longevity?? Will that be our next battle?? I have owned an operated a QUV for over a decade. You're in for a battle.

Since you brought it up - you shoot first !!!

A great weekend to all.

Howard
Express Films

BIG ANNOUNCEMENT COMING NEXT WEEK FROM EWF !!!!

You folks are way to smart for me; but here's the dividing line.

Marty is referring essentially to daylighting. Daylighting is a buzz word for any film with a light to heat ratio above 1.0 Luminous Efficacy.

The 70 VLT fits that description on VK 70 (at that time they were unique as Spectra-select-Hilite-prestige 70-had not been introduced)

Costs were and still high and while the darker films did knock down SHGC his point was (and probably still is) that in doing so your interior office lights would need to be turned on, worker productivity would go down because they would be starved of natural light (school children learn more, sick days reduced, etc.)

In terms of cost justification; Marty points out that the "ends did not justify the means" using darker metallic films!

The perfect balance is a light film that improves productivity, reduces interior lighting requirements, maintains the views that a luxury suite would expect and still reduces heat gain via the IR rejection coupled with the 30% vlt reduction.

There are numerous studies since this article was written that support his position. Commercial buildings would have to be educated concerning the benefits of a daylighting window film BUT if you can get them to agree that a % improvement in tenant productivity or satisfaction has an associated cost savings/benefit over a 30 year life cycle - the ROI becomes much more attainable.

I seen Asian measurements aka "--- standard" where they have sampled up to three wavelengths in the NIR and averaged out an IR rejection percentage. The highest I've seen is 99%! Maybe they try for 99.9%? Funny thing is that these films at the supposed 99% IR rejection only reject about 49% TSER or .51 SHGC.

I really don't pay attention to IR specs unless I see someone trying to infer that it is a total performance measurement or trying to pull the BTU meter slight of hand. I've blogged plenty of my thoughts on that so no needs to be repetitious here...

Since you were talking about VLT and energy and you have some QUV experience. I have heard from a close friend that some popular films exposed to QUV and Xenon are "lightening up" after low exposure times. So the question would be "how is the performance of a film affected when it loses its ability to filter visible light over time?" Wouldn't it stand to reason that if visible light is responsible for 49% of the solar spectrum then a film's effectiveness to reject energy decreases as it "fades" from exposure and its VLT gets higher?

Some of these miracle films out there are not what they are made out to be.

Funny coincidence I just had a similar conversation yesterday about these new ir films that are out there and the soon to be released repackaged 3M ceramic 30.

Huper Optik needs to quantify these comparisons under xenon lamps and advanced weathering studies done by an outside objective laboratory (they can do it themselves first and than send it to an independent if that makes them feel better about the cost)

If they don't these knock-off Korean films and the look-alike suntek ulv and "ceramic" 3M re-boxed will all look the same or better on paper (their sales brochures and websites) Why some may work even better at an angle once it pops out of their box.

That's what I like about V4V, where I stop short of mentioning names he's all ahead full!

In the interest of "capping things off":

There is absolutely nothing wrong with putting a 35% Neutral VLT film with an SHGC of 0.42 (ballpark) onto a building with a heat load complaint. It's much better than putting an ultra-expensive SS film with an SHGC north of 0.55 on there. They are NOT going to have to augment their lighting as a result, the cost will be much lower, payback time quicker and the occupants will be cooler.

I am a film distributor. I have not installed a piece of flat glass film (for hire) since 1984. However, if I did go out on a sales call and you were selling that ultra high $$ SS product with the ultra high SHGC, I am very confident that I could convince the customer to follow NFRC guidelines, spend less money, recoup their investment faster and save more energy. All without augmenting the lights.

VC:

Let's not go to far on this thread (with the new topic you raised). I just want to point out some of my limitations here.

I have no ability to do solar performance testing. I have to pay the lab to do that. I can, however, measure VLT on the glass. If the VLT is increasing, we can make the reasonable judgement that TSEt is increasing, but to what degree that is, I do not know. We would need to send it out for testing. So, in answer to your question about how the solar performance is degraded upon exposure - the answer is - I don't know !!!

I use that QUV to evaluate the two properties that most concern me as a distributor. I want to know if that adhesive is going to give way and I want to know if that color is going to change to a degree to where it's going to produce a warranty claim. If the film does not hold up in comparison to it's peers - it won't make it into our catalog.

You raise a good point. How much does solar performance degrade over time?? I suspect it does, but to what degree, I do not know.

Let's leave it for a new thread.

Are we all done on this ???

-Howard

Im good with it

I don't have the #'s but I would venture to guess that it would be significant especially if the film is using IR dye then it could be substantial due to the failure of IR absorbtion. Whatever the exact # is the irony of it all is that we were talking about high VLT SS films lacking performance due to high VLT and now it looks like some lower VLT counterparts will ultimately "catch up" in VLT and perhaps in lowering performance?

Nice subject to kick around. If we can get some conclusive info, man... I think I feel a blog coming!

whos on first? ....Do you know what I mean

Too much reading... you people are too smart... I read the article and I think its a bunch of hogwash

Im learning thanx guys