How to test if windows have Low-e coatings?
Last Post 28 Aug 2010 11:02 PM by BlackHatch. 15 Replies.
Printer Friendly
Sort:
PrevPrev NextNext
You are not authorized to post a reply.
Author Messages
GAWUser is Offline
New Member
New Member
Send Private Message
Posts:16

--
24 Jun 2010 08:09 AM
I installed new windows and balcony doors on a home I'm building. Windows and balcony doors were supposed to be energy efficient, dual pane, with low-e coatings however, I've noticed there is a difference in sun's heat transfer between the windows and the balcony doors. Balcony doors seem to let sun's heat through a lot more.

I'd like to get the windows tested for efficiency or just the low-e coating.

Anybody have experience or suggestions with this?

Thanks
jonrUser is Online
Veteran Member
Veteran Member
Send Private Message
Posts:4171

--
24 Jun 2010 08:02 PM

I can usually see a low-E coating just my looking at the window. But a piece of black sheet metal held on the inside and an IR thermometer reading would give some numbers.
Bruce FreyUser is Offline
Basic Member
Basic Member
Send Private Message
Posts:429

--
25 Jun 2010 03:35 AM
There are many different types of glass coatings. Low-E is designed to keep the heat inside and is important in the winter. Solar heat gain is a different issue and there are different coatings for high and low solar heat gain solutions. What jonr proposes will reveal solar heat gain differences. Low-E is almost a given in any good window today. I do not know of a field test for Low-E.

If the coatings are different you may be able to see the difference if the wndows and doors are on the same wall.

Don't overlook the possibility that a light of glass has been installed inside out.

Bruce
GAWUser is Offline
New Member
New Member
Send Private Message
Posts:16

--
25 Jun 2010 10:05 AM
You can see a difference in colour between the typical windows and the balcony door glass. The windows seem to lighter or more reflective than the balcony doors.
We had a similar issue on a large window that was installed on the house, where two panes were darker than the rest of panes within the same window unit. Maybe these panes were installed inside out.

passivesolarUser is Offline
New Member
New Member
Send Private Message
Posts:10

--
26 Jun 2010 03:37 PM
To test and see if the Glass has been installed inside out check both exterior and interior surfaces with a voltmeter that has a continuity check. LowE is conductive and if the low E is on the outside surfaces of the glass you can touch it with the probes and will get continuity(put the probes about 1/2" apart directly on the glass surface). The most common LowE is supposed to be on surface #2 or the inside of the exterior lite of glass so I would check the outside surface first. That is one, if you know a glass installer some have a device made by ETEKT to test the placement of lowE in the window They cost about a $190 US but can be useful as more windows than you think are assembled wrong. As stated in an earlier response you may feel a significant difference in the suns power as there are literally thousands of lowE coatings made by numerous manufacturers. A better low budget check is on the cool days or nights is one window interior surface significantly warmer than the door.
jonrUser is Online
Veteran Member
Veteran Member
Send Private Message
Posts:4171

--
26 Jun 2010 05:41 PM
Probably a good reminder that "low-E" is meaningless unless one specifies just how low-E with a SHGC figure.

It would be interesting to know of a test for the R value also (say to check for argon fill) - perhaps some type of heater that attaches to the glass and then measures the heat transmitted to the other side.
GAWUser is Offline
New Member
New Member
Send Private Message
Posts:16

--
28 Jun 2010 08:35 AM
Good tips!

I will try the conductance test today.

I haven't gotten any SHGC figures from my supplier but I will ask them for it.
fenestrationmanUser is Offline
New Member
New Member
Send Private Message
Posts:3

--
29 Jun 2010 03:51 PM
I used to use a disposable lighter.  Clear glass and the low e coating will have a different flame color.  You just need to know where the low e surface is.  Fairly primative.
ADCUser is Offline
New Member
New Member
Send Private Message
Posts:15

--
02 Jul 2010 01:23 PM
Posted By fenestrationman on 29 Jun 2010 03:51 PM
I used to use a disposable lighter.  Clear glass and the low e coating will have a different flame color.  You just need to know where the low e surface is.  Fairly primative.

But it works quite well.
fenestrationmanUser is Offline
New Member
New Member
Send Private Message
Posts:3

--
02 Jul 2010 02:00 PM
ADC

Did you try the lighter idea, or have you done this method in the past?
Bruce FreyUser is Offline
Basic Member
Basic Member
Send Private Message
Posts:429

--
03 Jul 2010 05:14 AM
Could you expand on the "lighter test"?

It would seem that any glass with a coating will appear different than clear glass of the same thickness. Coated glass also looks different whether it is viewed inside out or outside in.

Can it be used to identify the type of coating (i.e., identify low-E or solar selective)?
Bruce
GAWUser is Offline
New Member
New Member
Send Private Message
Posts:16

--
05 Jul 2010 07:42 AM
Is there a safe way of doing the lighter test? I imagine it's very damaging to the coating, or does it take a while to burn through it?
BRINDASBABYUser is Offline
New Member
New Member
Send Private Message
Posts:26

--
05 Jul 2010 09:09 AM
the low-e should be on the inside surface of the glass away from you are so you will not be able to burn it in anyway.
Thank you, Matthew Burr Window & Door Buyer Village Home Center 4650 Hwy 7 North Hot Springs Village, AR 71909 Office: 1-501-984-6074 Fax: 1-501-984-6073 Email: mburr@cbmcci.com
Bruce FreyUser is Offline
Basic Member
Basic Member
Send Private Message
Posts:429

--
06 Jul 2010 06:49 AM
I don't think the "lighter test" is meant to burn the coating (which as brindasbaby points out should not be exposed). I think it is the difference of the flame color when viewed through the lite of glass in question that is being observed.

My guess is the 'lighter test" will help you tell if two lights of glass have the same or different coatings, but nothing more.

Bruce
bobarchitect39User is Offline
New Member
New Member
Send Private Message
Posts:26

--
23 Jul 2010 11:45 AM
They do make specialized low-e "detectors" but they may not be worth the investment if you can use something more widely useful, like the voltmeter (or lighter!). I have also heard that if you hold a flashlight at a really steep angle, the reflection off a low-e window should be a different color than normal. Don't know if this actually works though.
BlackHatchUser is Offline
New Member
New Member
Send Private Message
Posts:50

--
28 Aug 2010 11:02 PM
Lighter test does not reveal the type of coating, just the presence of it.

Double pane glass with low-e = 3 flame reflections with the one reflection being of a greenish tint.

Double pane glass with double low-e = 4 flame reflections with two of the reflections being of a greenish tint.
You are not authorized to post a reply.

Active Forums 4.1
Membership Membership: Latest New User Latest: maverick09 New Today New Today: 4 New Yesterday New Yesterday: 6 User Count Overall: 28578
People Online People Online: Visitors Visitors: 243 Members Members: 18 Total Total: 261

GreenBuildingTalk

Welcome to GreenBuildingTalk, the largest, most active forum on green building. While you can browse the site as a guest, you need to register in order to post.

Register Member Login Forum Home

Search Directory

Professionals Products

Get Free Quotes

Tell us about your building project and get free quotes from green building professionals. It's fast & easy! Click here to get your free quote.

Site Sponsors

For Advertising Info:
Call 866-316-5300 or 312-223-1600

Professionals Serving Your Area:

Newsletter

Read the latest GBT Newsletter!

Copyright 2011 by BuildCentral, Inc.   Terms Of Use  Privacy Statement  Free Quotes  Professional Directory  Advertising Programs