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Where are all the Flat Glass Guys

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TD convinced me today I should post more. I have read this site almost everyday for the past 10 years but have not participated much, because I have tried to maintain a professional distance and not spam and self promote. 


I guess for my 1st real post I would like to discuss flat glass. Our company started out doing just flat glass but our automotive segment has grown tremendously. Flat glass is the reason I got in the business though. I wanted to save people money on their energy bills.


It seems lately like flat glass has lost its momentum. I have seen this internally and notice there are fewer FG post on this board. I used to have customers adding flat glass to auto but now my flat glass dealers are asking about auto.


I have seen the recent studies that say solar control film is going to grow by 90% in the next 3 years. But from my experience consumer awareness is still super low.


I know I am to blame for this as well. As a window film professional I should do more to advertise the benefits of window film to end consumer. This was our original idea. The problem we had was converting this advertising into product sales. Customers would seek multiple bids and dealers would offer other products.


You might not know that my partner and I started Geoshield and another company that distributed solar panels. Solar panels in my opinion are an inferior product to window film but they have much better marketing and awareness. I actually did a study showing that 300 sqft of window film would save a customer more power than 300 sqft of solar panels would produce in a year at 1/10th of the cost. My partner is now running the solar panel company and I am running Geoshield because I believe window film is a better energy efficient product.


I believe the problem is lack of organization. The solar market is much more organized. Manufacture’s have distributors with protected territories, distributors have dealers with exclusive agreements. MSRP are used. Products have more transparency although they are just a commodity like window film. Marketing is direct and focused. Organizations and groups are professionally working together to advertise the benefits. Regulations, checks and balances are in place.


I have seen the same advances in window film but they are often underutilized  i.e. Exclusive dealer programs, IWFA solar control certifications, NFRC, Window Film Mag, window film groups on tintdude, linkedin, facebook, etc. In the end I think window film lacks credibility.


I am as guilty as anyone. As a small company we have not gotten NFRC certification, we are not members of the IWFA, I do not participate on social media enough, we do not advertise the benefits of window film to end consumers. We do not heavily promote exclusive territories. And there are a million other things I can list that we could do better and I always make the excuse it cost too much. Well I think that it is going to cost us more if we don’t start doing these things. I know I am going to start trying more. Sorry this kind of turned into a sad apology letter. 

Edited by Burns

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Here is an old video i found of me demonstrating my hypothesis of window film vs solar panels. 




go to 7:49 to see hypothesis. or watch it all and see me piss off some solar panel guys. 


This was done 3 years ago for Louisiana Department of Environmental Quality. The had expo where they vetted energy efficient products against each other. 

Edited by Burns

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I agree, the FG talk has fallen off here as of late. Auto chatter does not interest me at all. So as a result, my participation has fallen off as of late.

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Ok lets talk energy savings then. How can i improve the following to get more accurate numbers when a manual reading is required? I do this when i can not adequately model with LBNL windows do to limited testing on specific glass types. 



Simplified M&V Guidelines for Application of Window Films




The installation of window films decreases the window solar heat gain coefficient (SHGC) and reduces the solar heat transmitted to the building space. During months when perimeter cooling is required in the building, this measure decreases cooling energy use.


These simplified M&V guidelines developed for this project are applicable for window films

applied to south-east facing windows only. The measure demand and energy savings

are calculated based on the window-film area; change in solar heat gain coefficient; and cooling

equipment efficiency.


Pre-installation Site Survey


The goal of the pre-installation site survey is to identify the existing window characteristics and determine post installation SHGC.


1. Take a BTU meter reading outdoors on a clear sunny day on an  exposure facing the sun. Move the BTU meter until you obtain a maximum reading. This is Reading 1.


2. Take a BTU meter reading indoors on the same day, on the same exposure, approximately 1 foot from the window. Move the BTU meter until you obtain a maximum reading. This is

Reading 2.


Note Value of Reading 2 divided by Reading 1. Repeat process once sample film is applied and you can determine the SHGC before and after.


Readings: Building 1

Reading 1= Exterior: 260

Reading 2=Interior: 90

Reading 2*= Iris70: 65


90/260=.35 SHGC Pre Instalation

65/260=.25 SHGC Post Instaltion



Calculation of Energy Savings


The window film demand and energy savings result from a reduction in demand and

energy use of cooling equipment. The savings estimates rely on tabulated values of solar heat gain factors (SHGF) as published in the 1997 ASHRAE Fundamentals, Chapter 29, Table 17. The ASHRAE data represent the amount of solar radiation that is transmitted through single-pane clear glass for a cloudless day at 40o N Latitude for the 21st day of each month by hour of day and solar orientation.


Source: http://engineering.dartmouth.edu/~cushman/courses/engs44/SHGF-daily-totals.pdf



                      Daily Total- Btu/hr-ft2-day


























To determine cooling energy savings associated with window films, the ASHRAE SHGF

data are averaged into daily totals from April through October. These averaged daily totals are multiplied by 150 days which is the average number of cooling days, based on ASHRAE, Solar Heat Gain Factors at 40o N Latitude.


Sum Daily Total for Cooling Months/Number of Months= Averaged Daily Totals




1,142.43 Btu/hr-ft2-day x 150 days= 171,364.50 Btu/hr-ft2-yr


The solar gain values are translated to electric energy savings by considering the cooling equipment efficiency. In the calculation, the cooling equipment efficiency equals the rated efficiency of the installed equipment or the ASHRAE Standard 90.1-1989 minimum cooling equipment efficiency (see the Cooling Equipment Standard Efficiency Tables), whichever is more efficient. A Coefficient of Performance (COP) of 3.0 is assumed for these calculations.


The equation below presents the annual energy savings calculation for window films. The total

annual energy savings is equal to the sum of the savings determined for orientation, as

shown below.


Equation: Calculation of annual cooling energy savings



kWsavings,d = Demand savings per window orientation.

Afilm,o = Area of window film applied to orientation (ft2).

SHGFo = Peak solar heat gain factor (Btu/hr-ft2-yr) for orientation of interest

SHGCpre = Solar Heat Gain Coefficient for existing glass

SHGCpost = Solar Heat Gain Coefficient for new film

COP = Cooling equipment COP or SEER based on ASHRAE Standard 90.1-

1989 or actual COP of equipment, whichever is greater.

3413 = Conversion factor (Btu/kW).


kWsavings,d= Afilm,o x SHG x (SHGCpre – SHGCpost) / 3413 x COP


Example: Window films are installed at Building1


Orientation= South East

Area (ft2)= 18,662

Window SHGC (baseline)= .35

Window SHGC (w/films)= .25

SHG(Btu/ft2-yr)= 171,364.50


18,662 ft2  x 171,364.50Btu/ft2-yr  x ( .35SHGC- .25SHGC) / 3413 x 3.0 = 31,233.56 KW Savings

31,233.56 KW x $.105 cost per KW = $3279.52 Annual Savings

Edited by Burns

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At would appear as though you have a good technical background in window film. All the sizzle with the stats and numbers can be a intimidation for Joe consumer. And from my experience, the energy companies have their own formulas they like to work with. But I'm sure this thread will bring out the FG tech experts.

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Half the time that method never works up in the PNW because it is always cloudy. Bottom line you need to get your films into the IGDB, I did 6 audits today and if we used that method it would take a week.

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I have audited the classes to be a NFRC ACE and I am well versed in IGDB, WINDOWS7 and CMAST. I have my own private library i created here at LSU and with the help Marles Mcdonald at QTI using NFRC standards. I also have excel calculators that i have built. I have seen wild variations from what I believe the actual numbers will be and what generic software puts out. 


My questions is what do you do when the glass is specific and not just clear, tinted etc and you want an exact number. I can't test our film on all glass types and thickness. 

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It seems lately like flat glass has lost its momentum. I have seen this internally and notice there are fewer FG post on this board. I used to have customers adding flat glass to auto but now my flat glass dealers are asking about auto.



I think there are a few reasons for this. Auto seems to be somewhat easier to market. Almost everyone owns a car and drives in the sun, where not all home owners can benefit from tint. So the market, while perhaps growing, is smaller. Auto also doesn't seem to be as complex in terms of which films are ok, so a higher learning curve in that aspect then auto. 


Auto takes much more skill, installation wise, generally speaking. And people seem to not really care about the quality of the tint job they get for $99... 


FG - you make your own market. Yeah.. you can sit back and wait for the phone to ring, which it will, but it seems to me at least that you need to do proactive marketing rather then passive. 



Just my  :twocents

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