Ceramic film is a gimmick in real world situations

vquestfilms.com · May 20, 2015

:yeah Nice post Howard :thumb

Thirtyfive · May 21, 2015

Show me a man who thinks ceramic films are a "gimmick" and I will show you a man that does not understand luminous efficacy, which is the "holy grail" of window film design/engineering.

-Howard

rvpjr · May 22, 2015

Howard is tha man.

EWF · May 26, 2015

Howard is tha man.

Thanks Ralph. It was great to speak with you again last week. We really need to sit down over a brew one of these days. Maybe SEMA 2015?

Until then, take care and be well.

Regards,

Howard

TomTint · May 27, 2015

I really have no skin in this ceramic game, but I think there should be a more involved test method that is designed to show real world conditions that we see in the field. For example, window film can only do 3 things with light and heat. Absorb, transmit or reflect. That's it nothing else. If a film is very light and non reflective it is going to be absorbing heat in order to reduce SHG. This is what the ceramics do. These films heat up faster and hold heat longer than many films with similar TSER of the reflective segment. So how is this longer duration of heat accounted for inside a car ? A warm window is essentially a radiator, giving off its heat to the inside of the car.

EWF · May 27, 2015

Hi Tom,

You are 100% correct (as usual). Only three things can happen: Reflect, Absorb, Transmit

Reflected is always the best because that energy is gone (diverted away).

Transmitted is always the worst - that energy will be absorbed by the interior surfaces and get re-radiated at longer wavelengths. This will heat up the cabin

Absorbed is just a little more complicated, because some portion of this energy will be radiated outward and the balance will be radiated inward

As you point out, the Ceramics are high absorbers. But the volume of absorbed/rejected energy is preferable to direct transmission, which is a net positive in terms of total performance.

I hope I did not just add a layer of confusion.

-Howard

TomTint · May 27, 2015

So Howard, .. Let's take a standard silver 50 something film and a ceramic of lighter VLT but equal TSER. +\-. The Silver will reflect the majority of the TSER off the glass and out. Where as the ceramic would retain the heat, thus become a radiator giving off the absorbed heat inward afterwards. I imagine as a ceramic, it would also hold heat for longer timeframes than a silver of equal TSER, because of the construction differences in the two films. Is this accounted for in any test data ?

EWF · June 1, 2015

Hi Tom,

Yes. It is accounted for. The total amount reflected, absorbed and transmitted will always = 100. It is the ratio amongst these 3 numbers that tells you how the film works.

As you correctly point out, the Silver will attain most of it's performance by reflection. The Ceramic will attain the same performance at a higher VLT and a lower VLR by virtue of is ability to absorb the energy and selectively filter the wavelength. Approximately half (or more) of the energy will be re- radiated outward (the exact amount depends upon the particle size - some also reflect IR). Because the ceramic has the same TSER at a higher VLT, it also has the higher "luminous efficacy" which is the primary benefit of the ceramics.

Your example does raise an very interesting point however, because the Silver is a fraction of the cost of the ceramic and the TSER is the same. If we are dealing with a situation where inward visibility is not a requirement, which is the "smarter buy"? Same bang - fewer bucks. You get the picture. So in this case, the ceramic is not exactly a "gimmick" but the additional cost is not justified given the customers objective.

I speak to a lot of customers about film selection and I will always try to find them the least expensive film compatible with the customer's objectives. Ceramics are ideal for situations where you need the very best performance without reducing VLT any more than is absolutely necessary.

-Howard

vquestfilms.com · June 1, 2015

Not only is the radiant energy accounted for but you can plug a ceramic film's SHGC and Tvis into BIM software just the same as you can with a metalized film and determine KwH reduction. The KwH savings of comparable SHGC films in a building can be very similar in many cases and sometimes better in a whole building analysis due to the ceramic film's higher LE.

In automotive the IR filtration does affect the comfort level of the occupants even when the environment is conditioned by AC. For instance, the Ceramic 50 in my car feels much more comfortable to sit behind than the darker 30% vlt metal film in my other car.

Not all ceramics are completely absorbing, some ceramic films do reflect varying amounts of solar energy as well as absorb. you cannot accurately lump them all into the same basket. :twocents

Cost is a different issue. Different requirements necessitate different film technologies. Sometimes as Howard mentioned, you need less reflective technology, sometimes you need non-corrosive or even dye-free film. Ceramics give you those options but you have to pay for them... simple truth.

As far as gimmicks... I would say that a respected agency such the NFRC would never allow for skewed ratings to prevent an accurate apples to apples energy comparison on clear glass. And the NFRC does in fact have ratings for some ceramic films, good ones at that. :thumb

Metal is not the be-all / solve-all solution in window film and the same is true for ceramics. That is why we sell great products in both technologies.

Interestingly, they are starting to find out that metal reflective technology can buy you a massive amount of environmental liability if you are not careful. This will no doubt change the way we spec films in some instances.

Edited June 1, 2015 by vquestfilms.com

EWF · June 2, 2015

Great post Rob.

I think the take-away here is that you really need to acquire a working knowledge of what a particular customer's solar control objectives are and what film(s) are compatible with their goals. If (for example) a customer wants to cool off a space and does not mind a high VLR film, that customer may be better served by Silver 15% than by a more expensive ceramic alternative.

-Howard