EXPRESS FILMS EXPERT QUIZ #1 - OCTOBER 2011

[vquestfilms.com]

Everyone has a different nuances in their data interpretations.

All the more reason to use a BTU meter!

-Howard

You may want to verify what range your BTU meter reads. I believe it runs contradictory to you IR rejection beliefs.

KS M 3832 testing standards. Can you explain what these are?

No. I do not know what that is.

What about the "Nexfil Method?"

[EWF]

What about the "Nexfil Method?"

I do not know that either. It sounds like a proprietary metric. Unless and until other manufacturers adopt it (whatever it is) I am not sure I would use it as the basis of a film vs. film decision.

-Howard

[EWF]

You may want to verify what range your BTU meter reads.

apx 250-1250nm. We went over this in a previous thread. The overwhelming amount of incident solar energy that reaches the earth falls within this bandwidth (i can post that graph if you like).

If you are making the point that the meters don't do the job, please call EDTM. They disagree.

-Howard

[vquestfilms.com]

You may want to verify what range your BTU meter reads.

apx 250-1250nm. We went over this in a previous thread. The overwhelming amount of incident solar energy that reaches the earth falls within this bandwidth (i can post that graph if you like).

If you are making the point that the meters don't do the job, please call EDTM. They disagree.

-Howard

Howard,

No more graphs please. You are not understanding what I am asking. Let's sort this out first to get to the facts.

Which BTU meter are you using? EDTM? If so then what model #?

[EWF]

Which BTU meter are you using? EDTM? If so then what model #?

You sell them Vq. For the sake of this discussion, lets consider them all. The one I have might not be the same as someone else reading this post.

-Howard

[vquestfilms.com]

Which BTU meter are you using? EDTM? If so then what model #?

You sell them Vq. For the sake of this discussion, lets consider them all. The one I have might not be the same as someone else reading this post.

-Howard

Each meter does something different for ex. VLT/UV meter is not the same as the BTU meter. There are a lot of inexpensive BTU meters that only measure 900-1100nnm so for the sake of this discussion let's take the EDTM BTU meter, a fine high quality instrument that measures a much wider range of 300-1100nm (I hope this is the one you are using otherwise you are probably only measuring NIR 900-1100nm) and use it for an energy analysis.

Can it measure the full solar spectrum? No

Can it determine the SHGC of the window with film applied? No

Can you use the BTU reading and convert it into SHGC? No

Can you take that BTU reading and use it in LBNL software to do an energy analysis? No

Can you use this meter to determine whether you qualify for EPAct or PUC rebates? No

While the EDTM BTU meter is great for indoor demonstrations where there is no natural light, it even works great in a residential demonstration in natural light, however it is the wrong instrument to use for energy analysis and estimated savings/ROI. You cannot quantify to a consumer how much energy is transmitting through the window and this is what you and I are so passionate about Howard. Most other meters measure only infrared, and if you use an IR lamp then you are also only measuring mostly IR energy.

I am a firm believer in using quality equipment. As much as I believe EDTM makes the finest handheld glass inspection and solar measurement meters, and as much as I would love to sell a ton of these meters. I cannot in good conscience suggest that this particular tool will work for an unintended purpose that being total solar spectrum measuring. It just does not do that. There is another meter that calculates the SHGC on glass and some exciting new stuff coming on the horizon that will measure film and glass at even wider bandwidths. I can't wait to play with these new toys.

[EWF]

Can it measure the full solar spectrum? No

It measures 93%+ of the energy at those wavelengths that penetrate the earths atmosphere and reach the earth's surface. There is radiation above 1300nm but it is a small factor and much of it is blocked by atmospheric moisture.

[EWF]

Can it measure the full solar spectrum? No

Can it determine the SHGC of the window with film applied? No

Can you use the BTU reading and convert it into SHGC? No

Can you take that BTU reading and use it in LBNL software to do an energy analysis? No

Can you use this meter to determine whether you qualify for EPAct or PUC rebates? No

Can I use it to make an informed in-the-field decision about Film-A vs. Film-B?

Definitely + Positively + Absolutely, because as you can see in the graph, it is metering the overwhelming majority (but admittedly not all) of the energy. Let's not have the perfect being the enemy of the very good. Rather than relying upon a model, a simulation and/or a computer program, you can see exactly how well a film is doing on that customer's glazing, in their building, at their lat/long.

I too welcome the arrival of the broader spectrum meters. I am using the 300-1100nm model.

BTW: A non contact thermometer can also be used to compare Film-A to Film-B by measuring the temperature change of a nearby substrate behind two different films.

-Howard

[EWF]

Are we absolutely certain that LBNL is considering 250-2500nm anyway?? I am not sure we have even established that. The reason I ask is that I have searched around with laboratory equipment manufacturers and nobody had a model that went anywhere near that high anyway. LBNL does not make their own gear. They buy it on the lab supply market and as far as I can tell, there are no units (I could find) that go that high.

Does anyone have the email address for a contact person over there? I would be glad to correspond directly with them and find out. Please email me his/her email address.

If LNBL stops at 1300, that would put an entirely different spin on this discussion. I really would like to find out.

Thanks,

Howard

[TomTint]

Who's on first