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kate7047

questions about pgt and impact glass in fl

kate7047
16 years ago

I am (still) researching impact glass replacement windows for my home in Ft Lauderdale. PGT is a major player in Florida. I am however disturbed by their lack of Energy-Star rating on their impact glass Miami-Dade cert. windows. The glass is monolithic with no air space. (Perhaps monolithic is the wrong term, but I mean glass-PVB-glass all laminated together as a single slab.) I cant even find data on their website for U-factor and SHGC for these windows. The data given seems to be for their non-IG dual pane windows. And even these windows donÂt seem to have particularly good values.

In my researching I discovered that there seems to be a dispute as to the relative importance of U-factor vs SHGC in this climate. I have ZERO heating days but probably 330 cooling days and a beastly sun beating through my windows much of the year. Is low-E (or low E2) really that important in my climate? Will it keep heat out and cold in? And does anyone know where I can find data for PGT impact glass windows for U factor and SHGC? I need to replace my aged windows irrespective of getting hurricane windows, and I already have hurricane panels which are a PITA to install, but maybe I want to get regular (ie non-IG) windows installed with low-E2 dual panes and just continue to live with my old shutters. Price plays a big role here too as the IG windows are probably 3 times more than ordinary windows.

Also, can anyone give info on the benefits/drawbacks to aluminum vs vinyl windows in south Florida? Unlike the rest of the US, it seems that the vast majority of new and replacement windows here are aluminum. Yet aluminum seems pretty miserable thermally-speaking.

Comments (41)

  • kate7047
    Original Author
    16 years ago
    last modified: 9 years ago

    Wow, Oberon! Thanks SO much for that thorough explanation. It really is complicated. (BTW, I was incorrectly using IG to mean "impact glass". My mistake.)

    So it seems the Energy Star designation is somewhat irrelevant to the Florida market if virtually NONE of the impact windows can get that designation. I presume it was mainly developed for cold climates where heat loss is of prime concern. IMHO, it would be helpful if "they" (ie the energy-monitoring powers that be) would give us hot-climate people a useful designation for our needs. I mean, it's not a small market.

    In my snooping, er, researching online I came across comments submitted by industry representatives to the Dept of Energy a couple of years ago seemingly attempting to get a variance to permit Energy Star designation in the southern market. It was quite arcane, but it appears that they GOT the modification and yet still can't get the efficiencies good enough to get the designation. (Amazing what you can find online though!)

    Unfortunately, I want it all. Impact glass, top notch SHGC and affordable price. Guess something will have to give. Phooey. But again, many thanks for your help!

  • oberon476
    16 years ago
    last modified: 9 years ago

    Dade, Broward, and parts of Palm Beach county require Dade impact standards. The rest of Florida may or may not depending on local restrictions. Outside of those three counties, you have a greater liklihood of getting thermally efficient impact products.

    Energy performance requirements are probably going to get a good bit more stringent in your part of the world in the next few years, but they are still mostly ignored because you live in a warm climate and many (most?) people in your part of the world think that energy performance is a cold-climate thing.

    As you said though, you want three things "Impact glass, top notch SHGC and affordable price", and in reality you can get two of them but all three at once is going to be more difficult...

    But, in the long run, thermal efficiency and safety count for alot.

    And you are very welcome. And if you have additional questions, please feel free to ask. There are a number of pros who visit this site and there are a lot of good answers here.

    Have a great evening!

  • mrsdaisy123
    16 years ago
    last modified: 9 years ago

    PGT is a great product, I put in my home in East ft. Lauderdale. I am so happy with it. It really reduced the heat in my home. I used a company by the name of Window Man of South Florida, a young man by the name of rick was really nice and spent time explaining everything. Very well educated I have to say. He even followed up with a phone call a couple of weeks after they installed my windows to see if i was happy. Can you believe it, in South Florida to find that kind of service was very surprising to me. I would recommend him to anyone.

  • rrschwab_optonline_net
    12 years ago
    last modified: 9 years ago

    On a Hurricane Impact Glass Window, with LoE, why is the single glass facing the outside? it seems that if it was hit by a twig or a branch of a palm tree, it will easily break. The Impact glass is on the inside of the window facing the interior of the home.

    Also, why does the film on the glass have to be green, when most glass has a "dark" or "black" film on it to protect it from the sun. I would appreciate your answering these two questions. Thank you.

  • agape1939_aol_com
    12 years ago
    last modified: 9 years ago

    What would be the u-factor and SHGC for solar ban 70xl

  • GulfBreezeWindows
    12 years ago
    last modified: 9 years ago

    Rozanne: The single glass is on the outside for saftey. If something comes into the window, the impact glass "flexes". So if the impact glass were on the outside, and the single pane glass were on the inside, it could shatter the glass into the home.

    The film between the glass is not green, it is clear. Some get green glass tint or darker shaded tint depending on were they are. A few years ago people got green tint on there windows to help with turtles, but it actually doesn't help that much. Now they go more on how dark the window is in turtle areas.

    James: 70xl will depend on what type of window. Usually U: will be around .30 - .27 and SHGC around .21. Again it depends on the setup.

  • PRO
    Windows on Washington Ltd
    12 years ago
    last modified: 9 years ago

    The green that you are seeing is as a result of the Low-e and not the lamination of the glass.

  • kate7047
    Original Author
    12 years ago
    last modified: 9 years ago

    Funny that this thread has been revived. I am the original poster from 4 years ago, and thought I would add a follow-up. I eventually bought PGT WinGuard aluminum windows, a total of 8 casements, 8 sliding, 3 fixed and 3 single hung. 6 windows (on front) had Eterna Finish, which has held up just fine and looks really convincing until you are within about 12" of it. I did not replace my sliding glass doors (wish I had, but it was financial) and it ended up at just about $20K installed in early 2008. Replacement went smoothly with one problem which had to do with the muntin style only.

    Despite my concerns about energy efficiency, my electric costs dropped substantially (about 15%) immediately and have persisted. I used PGT's version of insulating glass and also tinted glass on the sun-drenched windows on 3 sides (not on north), but it's fairly subtle and not too dark and definitely not green. Admittedly, my old windows were really crappy and leaky, but just standing there with the sun shining through them, there was a very big difference in the heat transmitted.

    The windows continue to work well and I've had no trouble after 4 years. Of course, we haven't had any hurricane issues like in 2005 (I claim credit for this, as forking out $20K has kept the hurricanes away, IMHO) but it's nice to know I don't need to deal with those awful panels again. Style-wise the PGTs are boring and don't have the appeal of other brands, but they were affordable for me, got the job done and I can recommend them.

  • randd222
    12 years ago
    last modified: 9 years ago

    I'm still unclear if my South Florida home would benefit from double pane windows (without argon?!) or impact glass. In this instance, benefit is "be more efficient" in regards to keeping out the heat and keeping in the cool.

    We already have storm shutters (yeah, the kind I have to screw in when a severe storm comes), so I'm not concerned with the impact part. (Randomly: Heard one contractor state that only specially licensed contractors can install windows in Broward County and after a storm they're usually booked up so it's better to get regular windows which will ship faster and be installed quicker. Not sure if that's complete BS or not. I have nothing to base it on. Haven't been in South Florida for very long at all.) Our goal was to replace all the windows with new ones (since they're from 1980 and look like they're about 1/16" thick single pane and they're falling apart). But it's more complicated down here than we had anticipated.

    The details from this post are helpful, but haven't helped me completely understand exactly what I should be looking for in my specific scenario. Supposedly I want an SHGT lower than the VT... but I'm not sure what the base number should be. Again, supposedly, shaded windows should be 70-80% (how do I know what's best?!) and sunny should be 40-60%. And then I should look for the lowest SHGT I can afford... but I'm still pretty confused about the window glass itself, forget about the framing part! I have no idea if aluminum is better than vinyl for this area or what and there's very little I can find that definitively says one way or the other. :(

    Thanks for any guidance!

  • GulfBreezeWindows
    12 years ago
    last modified: 9 years ago

    randd222,
    I'm going to jump in on this and hopefully will just touch on some of your questions.

    You really want to look for a double paned IMPACT window. You can get it with LowE/Argon which is recommended. For all of Florida I recommend the lowest SHGC you can get, which should be around .21 for Vinyl windows.

    The strength you can get vinyl windows at, I don't push aluminum windows anymore unless it is a commercial job. PGT and most others have windows that meet Dade County requirements for vinyl Single Hung windows.

    If your in Broward, and do not have hurricane shutters, then I recommend the impact window. If you have Accordion or panel shutters, then you need to meet a DP50 and can go with a standard window.

    Hope this helps.

  • kate7047
    Original Author
    12 years ago
    last modified: 9 years ago

    Randd222-
    Whether you would benefit depends a bit on why you are replacing. My old windows were 30 years old, leaked (air) like crazy and really had to go. I already did have hurricane panels and every time I had to put them up, DH and I would spend many hours sweating and cursing the job. (It's ALWAYS 98 degrees and 100% humidity when a hurricane is approaching.) So we needed to replace the windows and NO WAY did I ever want to put up those stinking shutters ever again.

    That said, affordability played a big role. The PGTs were OK price wise and have given us significantly improved electric bills. We installed them in 2008 and now, 3 years later there are newer products available. (eg, when we did this PGT didn't have Dade-approved vinyl windows) But no regrets. I have had 3 years of no worries about shutters (What if I'm out of town when a hurricane is coming?) and the windows are really so much nicer than the old ones the other 364 days per year.

  • kimbo123
    11 years ago
    last modified: 9 years ago

    What would be the specs and recommendations to have an impact and security window in the same product? What makes a window classify as a security window, the hardness of the glass, the plastic inside?

  • websnooper
    11 years ago
    last modified: 9 years ago

    Based on your previous posts, shouldn't you figure this out?

    From your previous post........

    RESEARCH AND DO YOUR HOMEWORK and don't let contractors confuse you with all this talk about permits, EPA, product approval etc. All this info is easily obtained without much effort from the product itself or the internet.

    Seems to me is you are going to complain about price, you can take care of the heavy lifting on your own.

    At that point, you might as well hire the labor to put the window in and deal with any issues as well as they arise from being done improperly.

    Good luck and let us know how it goes.

  • millworkman
    11 years ago
    last modified: 9 years ago

    touche!!!

  • edgardenweb
    11 years ago
    last modified: 9 years ago

    Hello All,

    I have been "window shopping" (pun intended) for approximately 1+ year now and here is my story.

    So far I have gotten 6 estimates from different companies that vary from independent contracts, general contractors, contractor companies that do everything under the roof to specialty window companies and have a better idea of what to total cost will be for what I am looking for. That number (6) doesn't included me contacting several other companies (3+) and asking directly for the product that I want and finding out they don't cary what I want. I didn't want to waste time hearing a pitch I didn't need to for something I don't care for.

    Here is what I want:
    Double panel w/Argon gas filled
    Impact Glass on the outside of the house
    Low-E
    Tinted greyish
    Vinyl
    Zone 5 windows throughout the house (not varying 4's and 5's)

    Reasoning:
    double panes w/argon gas filled is much more energy efficient than single pane; the heat from the outside plus the sun light shining on the glass can transfer the heat inside
    if the single non-impact glass (aka "sacrificial glass") is on the outside of the house, it is much weaker than the actual impact glass and if a branch, rock or some sort of debris hits it with a certain amount of force, it will break. That's not to say it's not strong, but it takes less force to break that glass compared to the impact glass. Restated: Apply that same force with the actual impact glass on the outside, and it will not break for obvious reasons (but i'll state it here...impact glass has 3 layers thus making it more resistant to "minor" impacts)
    with Low-E coating, the transmission of heat energy is reduced by +-30% and keeps your furniture from fading
    with Vinyl windows, the transmission of heat is further reduced. With Aluminum, heat is transferred
    Zone 5 windows located on the corner of the house and Zone 4 windows located towards the center of the house. Given that info, during a hurricane, the pressures are higher in Zone 5's and those windows require a thicker rated glass for positive & negative pressures. For my preference, I would just like to make it even with the higher rating throughout the house.

    Optional:
    double hung over single hung

    I've found that only 2 companies manufacture everything that I have listed above, but specifically with the impact glass being on the outside; currently PGT and Gorell (i think). All of the other manufacturers that make a double pane impact window have the single glass (aka the "sacrificial glass") on the outside. I heard that the reasoning why they make it that way is because it's more costly to change the production line to make it the "correct" way.

    There was a comment above stating that the "single glass on the outside is for safety," but I highly doubt that is the actual reasoning as sales people will say anything to sell what they have and down talk about things they don't have and if you think about it, it makes more sense to have the impact glass on the outside rather than the inside. I had a contractor try to down talk vinyl and tried to sell the aluminum windows they carried, and unfortunately they were single pane only. The point is, people will say anything to make the sale.

    Thoughts?
    Questions?

  • EcoStarRemodel
    11 years ago
    last modified: 9 years ago

    I disagree that All salespeople will say anything to get the sale. Was there something else you wanted to know?

  • oberon476
    11 years ago
    last modified: 9 years ago

    Ed,

    I would guess that about half the window companies fabricating impact windows place the laminated lite exterior and about half interior - some do both depending on the window.

    There are a variety of reasons for the interior versus exterior replacement, but no one that I am aware of does it because "...reasoning why they make it that way is because it's more costly to change the production line to make it the "correct" way.". There are costs anytime a production line is changed, but flipping an IG in a sash is a non-issue from a cost standpoint; and honestly that reasoning is rather silly simply because there is no generic "correct" way to glaze an impact IG.

    One could even argue that keeping the broken glass of the sacriicial lite to the outside of the home versus inside the home is a valid reason for mounting the impact lite to the interior, but one could also argue that it's more of a "feel good" idea than reality.

    The decision to mount the lami lite to the interior or to the exterior in an impact rated window really has more to do with keeping the laminated glass in the frame in the event of a catastrophic impact and wind gust potential of a major storm than any other reason.

    Simply, impact or otherwise, window glass can be inserted into the window sash either from the exterior side or the interior side depending on how the window sash is designed. Window companies refer to this as interior glazed or exterior glazed (go figure).

    In either case, it's simply easier, and often allows for a higher DP rating (as it relates to impact and cycle testing), to secure the lami to the fixed window stop versus the removable stop when mouting the IG in the sash.

    As the name implies, the removable stop is removable. A window part that is designed to be removeable (and is often simply decorative and not structural) may not be the most practical location to secure the impact resistant lite of an IG into an impact resistant sash if you want said IG to stay in said sash in the event of a catastrophic event.

    And while securing the lami to the fixed stop isn't universal, and there are a number of excellent impact resistant windows where the lami side of the IG is not glazed to the fixed stop, it is generally simpler, stronger, and more reliable to glaze the IG in that manner.

    Is there an advantage to applying the lami exterior because it's more break resistant than the monolithic lite?

    If the sacrificial lite (and it is referred to that way with impact windows) is tempered and the lami lite is fabricated using annealed glass then the tempered monolithic lite will take a substantially greater hit without breaking than will the lami lite.

    Of course the tempered lite is going to leave a big hole in the window when it does break while the lami will stay in place whether it is broken or not.

    If the sacrificial lite and the lami lite both use identical 3mm glass, for example (lami has two 3mm lites bonded to the plastic interlayer, of course), there is no advantage to either glass per withstanding enough of an impact to break the glass. If a rock hits the monolithic glass hard enough to crack it, then that same rock will also crack the lami lite as well.

    Personally, I would strongly suggest to anyone looking for impact rated windows that they concentrate on the tangible issues such as company reputation, warranty (and how well the service it), reliability, and overall quality - no different than if you were looking for non-impact windows, or you were buying a car for that matter, the same advice holds.

    Let the window company design engineers worry about whether the lami is interior or exterior. Wherever they place the lami, the window still has to pass the same qualifications - interior or exterior.

    Regards

  • EcoStarRemodel
    11 years ago
    last modified: 9 years ago

    Simply flipping the glass in the frame would change the solar gain.

  • oberon476
    11 years ago
    last modified: 9 years ago

    "Simply flipping the glass in the frame would change the solar gain."

    Absolutely, and I actually did discuss the advantages and disadvantages of the LowE coating on the monolithic lite versus the lami lite on the original reply (with the intent of the LowE coating on IG surface 2 in both cases), but I deleted it before I posted because I thought that the reply was long enough without it.

    If there is any confusion, when talking about "spinning" the IGU in the sash I meant it as the difference between lami inside and lami outside and as part of a window company selling an engineered impact window and not a homeowner deciding that he/she wanted to reverse the location of the lami.

  • EcoStarRemodel
    11 years ago
    last modified: 9 years ago

    I got your point. I was just making an observation.

  • oberon476
    11 years ago
    last modified: 9 years ago

    It was a good observation and I agree totally.

  • Jboysma Richmond
    11 years ago
    last modified: 9 years ago

    Has anyone heard of Lawson impact glass and is it as good if not better than PGT?

  • PRO
    Windows on Washington Ltd
    11 years ago
    last modified: 9 years ago

    PGT is not likely making their impact glass.

    Get the specs on both and you can compare them side by side. Ask them who makes their glass.

    Post back with that information when you get and the big brain on Professor Oberon will answer all your questions.

  • JoanLast
    10 years ago
    last modified: 9 years ago

    Oberon (Obi Wan Kanobi:-) and fellow knowledgeable people,

    I have been trying to decide between 2 PGT products for windows and sliding glass doors. Why PGT? The man has done good work in our building and I believe he will stand by his work if there is a problem. My head has been spinning trying to compare and contrast all the choices. The current aluminum sliders are corroded. I am going for a vinyl product called PremierVue. The PremierVue line has 2 models. One has a PVB interlayer, the other a Sentry glass innerlayer. For sound attenuation, would you recommend one over the other? The STC, OITC testing was only done on the PVB model. The sentry glass model has higher DP ratings. My condo is on the 5th floor in a touristy area next to lots of live music. I am not allowed to change out the fixed glass (single pane) that is between the two moving windows. Therefore, I'm not sure how much difference for the sound perspective it will make by changing out the two moving windows and the slider to a better product. The two fixed windows will stay the same. I do think from an energy perspective it should help. The sun beats in with the current windows. Two of the four windows, plus the slider will now be more energy efficient. I called customer service at PGT. The man I spoke with at first said he didn't think there was a significant difference for sound attenuation between the two models. He then spoke with an engineer who said there might be a slight improvement with the PVB model. The condo is facing the gulf of Mexico, so hurricanes are a possibility. The original windows are from 1974 and so far no problems. The condo does do maintenance on them. Interestingly, the sentry glass model says it is energy star rated. The customer service man was not sure why the PVB model wasn't energy star rated. He felt they both should have been. Not sure if that was just an error on the chart...

    I would appreciate any thoughts or ideas. I would like to buy the best product for sound attenuation, energy efficiency, and hurricane protection. My problem is that the whole building would have to vote for me to change out the fixed glass. Half the building is much older and on a fixed income. They probably would not vote to let me replace the fixed glass. One they don't want it to look different and two they don't want any assessments down the road. It is crunch time and I need to order something. I appreciate any thoughts.

  • PRO
    Windows on Washington Ltd
    10 years ago
    last modified: 9 years ago

    I am sure Oberon will be along soon enough to chime in with some supremely technical background information.

    The higher DP number may be the result of a more rigid interlayer which probably translates to a lessened STC performance if I had to venture a guess.

    What is the DP in the window with the PVB option?

  • oberon476
    10 years ago
    last modified: 9 years ago

    "The higher DP number may be the result of a more rigid interlayer which probably translates to a lessened STC performance...".

    WoW that was some guess!!! It is exactly right, Sentry Glass is about 100 times more rigid than PVB and that translates into no significant STC advantage over a monolithic lite when using laminated glass with SG interlayer.

    That same rigidity also means that SG can potentially have significantly higher DP ratings over PVB as well, depending on application.

    PGT is one only two window companies (that I can think of at the moment) that fabricate their own laminated glass using PVB and/or SentryGlass (there are also a few window companies that laminate their own glass using resin lamination).

    I don't why PGT's SGP laminated glass should have better energy performance than their PVB laminates.

    If they only offered LowE coatings with SG then I could see it, but as far as I remember PGT offers LowE cotaings inside both SG and PVB monolithic laminated glass so I can't think of a particular reason for the suggested energy improvement.

  • PRO
    Windows on Washington Ltd
    10 years ago
    last modified: 9 years ago

    Oberon,

    Would the PVB interlayer glass provide more dampning over the stiffer SGP as a result of its less rigid nature?

    That was my comparison although I didn't word it too well.

  • JoanLast
    10 years ago
    last modified: 9 years ago

    Hi! I think the chart was wrong. On the detailed information, both the 2760 model and the 2860 model windows say energy star. Besides the inner layer difference, the difference I see is the negative design pressure for the 2760 is 60, the 2860 is 100.

    The first floor is about 17 ft. I'm on the 5th floor. I'm thinking I'm 47 to 57 ft up. It's Sarasota county.

    I get very grouchy when I am trying to sleep and I can feel the live music. I will also be working blinds, rugs, headboards, etc to help with sound attenuation down the road. I need to order windows and doors this week.

    Do we think the PVB inner layer is the better choice if sound is my biggest problem? Thanks for helping me keep my mind off my 16 year old son with a permit driving on 75 South!

  • PRO
    Windows on Washington Ltd
    10 years ago
    last modified: 9 years ago

    They do fly on that road.

    Crazy the last couple of times I was down there.

  • oberon476
    10 years ago
    last modified: 9 years ago

    WoW, you are correct, the advantage of PVB laminated glass is damping.

    Joan, we do indeed believe that the laminated glass with PVB interlayer is the correct choice if your primary consideration is sound control.

  • JoanLast
    10 years ago
    last modified: 9 years ago

    Thank you! Biting the bullet on Monday! Will be able to install 6 weeks after ordering. Almost in Tampa... Crazy rain. Good thing hubby is driving now!

  • JohnnyPre
    10 years ago
    last modified: 9 years ago

    What an informative and I guess, entertaining (to me at least) post. Being in the business (install & sales) nearly 15 years and still learned some things.

    Hope there are more threads like this as I have mountain of info/data/research to offer. Including direct line to some PGT 'PEOPLE' to help identifying your answers.

    Thanks.
    John

  • Eeyore63
    9 years ago
    last modified: 9 years ago

    Just joining this thread as I am looking to replace 1970's era awning windows with impact. Safety and energy efficiency are primary concerns. I need a lot of other work done on the house, so cost is also a factor. You have all been very helpful. So far I have been frustrated with trying to get estimates as I want to compare "apples to apples"

  • oberon476
    9 years ago
    last modified: 9 years ago

    Welcome Eeyore,

    I am going to recommend that you start a new thread and we can explore your options there rather than having to run thru this older one.

    Just a suggestion.

  • LillianBlessing
    9 years ago
    last modified: 9 years ago

    I had installed PGT aluminum windows in November 2014 by a local contractor. Condo regs. require aluminum. I got HR 210. . with solar ban 70 XL. My windows face east AND west. 4 piece Patio door (east) opens in the center. The glass and frame are hot to the touch. . . the east side is not comfortable during mid morning, the west side is not comfortable in the afternoon. I am disappointed. , I am considering getting thermal liners.

  • PRO
    Windows on Washington Ltd
    9 years ago
    last modified: 9 years ago

    What color are the windows?

  • kittles01
    8 years ago

    I am buying PGT windows and doors, the contactor said the track for the new sliding doors is higher than the builder grade sliders I now have. He said we will get use to stepping over the tract. Should we be concerned.

  • Windows on Washington
    8 years ago

    Not really. Most newer doors do have a taller track height. Unless you need ADA access, you will be fine.


  • veralix58
    7 years ago

    Greetings!

    I need some advise

    I lived in South Florida, and I am planning to install high impact sliding door (patio) that is on my master bedroom (HOT room). My master room is my HOT room in the house and receive DIRECT sun light all DAY (10 am to sunset) ! My main goal is to FIGHT the heat.

    I planning to buy a high impact sliding door with LOW-e 366 or 70XL.

    Measurements are: 108 by 81

    I have couple of quotes but I am confused. Some companies are advising for PGT Windguard 770 series and other CGI Sentinel . Some companies are telling to NOT buy insulated glass (filled with argon) due to possibility of outside glass could break.

    My questions are:

    1. Vinyl vs Aluminum frame. And really worth it

    2. If I add tint to an low e-366 or 70XL glass would increase my SHGC factor

    3. Insulation with argon gas, will leak? and How common this could happen

    4. How easy the exterior glass (thin) of an insulation door fill with argon could break?

    1. Does PGT and CGI used stainless screws?

    6. How I know that the door I bought has the low-e 336 or 70 glass I bought and not other lower version.

    Thank you in advance

    Thank you.



  • PRO
    Windows on Washington Ltd
    7 years ago
    1. Depends on what you prefer. Vinyl will be more efficient and is definitely preferred in colder climates, but that is not a consideration here. Both will work quite well.


    1. SHGC will go lower...which is good here.


    1. The newer spacer systems are quite good about gas retention rates.


    1. Not sure I understand the question here, but a well engineered product should be quite sufficient and have a long life with the spacer design and maintain the gas fill.


    1. Don't know. I am sure they could answer that for you with an email or call.


    1. Just look at the NFRC sticker and/or look up the CPD number.