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Windows: Inline vs. Comfortline Fiberframe vs. Alpen

alan72 | Posted in General Questions on

We are building in climate zone 5 – we were considering Andersen 100 series windows.  After a lot of reading on GBA wanted to improve the performance of our windows, so we I got quotes from 3 fiberglass window companies with Triple pane windows – U-factors are 0.20 and below – depending on the window types.

Alpen are the most expensive (by a lot).  Comfortline is in the middle.  Inline has the best prices.  They also have a tilt and turn window option.

Does anyone have experience with these window companies?

Also we are trying to compare visible transmittance of different glass options.  Is there a good resource for us to see the differences (we have a lot of windows in an area with an attached covered patio (15′ x 27′) and we are worried that Cardinal 272 triple pane or 366 triple pane with be too dark).


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  1. lance_p | | #1

    Subscribing. I'm considering fiberglass windows as well and I'm curious about your glazing questions.

  2. Expert Member
    BILL WICHERS | | #2

    Alpen gets their fiberglass frame pieces from inline. I’ve been working with inline and they’re very responsive, but I don’t have any of their stuff installed yet. If you’re anywhere near Toronto, inline has a showroom basically across the street from Pearson airport.

    The best reference I’ve found for coating transmission spectra and other IGU specs is this document from cardinal:
    Inline uses cardinal IGUs so all the info in there applies.

    I had been thinking the same thing you are regarding how dark the different coatings make the window, especially with a triple pane window. 366 gets pretty dark, and is really overkill on a triple pane anyway, in my opinion. 180 is the best for light transmission, but it costs you a little in terms of getting a bit less insulating performance from the window in the winter. If you look in cardinals technical glass guide, they give transmission spectra graphs and you can see how the various coatings drop off on the red side of the spectrum (longer wavelengths), which produces a bit of a bluish tint when severe enough. I’d recommend you go find a place with some glass samples you can look at before you commit to a particular coating.

    In my own case, I’m going with cardinals 180 and i89 coatings with 1-3/8” triple pane IGUs everywhere.


  3. Expert Member
    Akos | | #3


    I have a couple of Inline windows, all are fixed low profile, so I can't comment on the hardware quality.

    I have one triple pane with the 272 coating. If there is a clear window next to it, you can see the tint, but otherwise it is not noticeable at all inside. The coating does also provide a bit of privacy. For something that is west facing, you could probably even go darker to reduce afternoon solar gain.

    P.S. If you are getting decorative inserts like mullions, they are not as visible through the 272 from the outside.

  4. Expert Member
    Peter Yost | | #4

    HI Alan -

    any window with an NFRC certification has to report the windows Visual Transmission (VT). You should compare these values.

    But VT is only part of the story since it just reports the sum total visual transmission, not how it "favors" some color wavelengths over others (giving different color "hues" to different VT.

    Take a look at this report:

    and then yes, you need to actually see the different windows to get a sense of which ones are visually acceptable or not. Some people are totally unaffected by or even really see the differences while others are acutely aware. I had a client suffering from Seasonal Affective Disorder (SAD) who really found low-e coatings that rendered more "blue-ish" a problem.


    1. lance_p | | #5

      So to appreciate the difference between different IGUs, does the customer have to literally go to a window showroom to appreciate this? I'm wondering how practical that is, being in Ottawa and shopping for windows from a company in Toronto. What about those buying high performance windows from Europe? Do you just take a chance?

      I'm guessing that different combinations of coatings on different surfaces will mix differently, altering the spectrum of transmitted light, so the particular mix one is interested in needs to be available.

      I'm a little nervous about this now. My wife is the type who might not notice something like this right away, but once she does I'll never hear the end of it! Especially if I don't get her input ahead of time. I was kind of under the (mis-guided) impression that the biggest deal with low-E coatings was just a tinted looking reflection when viewed from outside. I guess I was wrong!

      1. Expert Member
        BILL WICHERS | | #6

        You’ll also get a slightly color shifted view of everything through the window, usually a bit to the bluish side. How noticeable it is depends on a lot of things. I doubt you’d notice it with the 180 coating, but you probably would with the 366 coating (I do, and I have some skylights with 366 which makes the sky a little bluer looking). The tint is most noticeable if you have differently coated glass panes in a place where they can be seen simultaneously (like on a shared wall or both sides of a corner). I would not mix coating types without some kind of divider to prevent the differently coated glass from being seen at the same time for this reason.

        If all your glass is the same, then you probably won’t notice the tint very much, but you might notice lower light levels compared to what you used to have. How much that bothers you depends on how sensitive you are. My guess is the 272 or 180 would be ok for you on a double pane, and probably even 366, but on a triple pane you might not like the 366. The difference in Visual transmission between 272 and 180 on a triple pane window is only about 6%, which you probably won’t notice, but most of that 6% of extra light loss is in the red end of the spectrum so there will be more of a bluish tint to the 272 compared to the 180.

        If you don’t want to make the trek to inline’s showroom (there are good food places around, you could make a trip of it :-), find a local window showroom. Anyone using IGUs from Cardinal glass will have the same coating options available, so you just need to find a showroom with displays of the different coatings so that you can look at them in person. Inline might even be able to refer you to someone if you call them.


  5. oldbungalow | | #7

    NFRC has a pretty good site that lists data for windows. I usually sort by U-Factor.
    see link below, as a recemt example. The first row is a tri-pane U0.17 window with 180, 180 and i89 coatings, it shows VT of 0.46. You can see all kinds of coating combinations and the impact on VT (though the grille/no-grille also has an effect)

  6. ethant | | #8

    I have inline windows. They were about 1/2 the cost of comparable performance windows. I'd say the hardware is noticeably wobblier than other, more expensive windows. However, I didn't want vinyl and I didn't want to pay for wood/alu... so fiberglass was the best option. They were responsive and easy to work with... some of the ratchets that finalize the window closure are hard close/open... we didn't get tilt turn.. i'm curious if tilt/turn would have a better/different operation... but I wanted internal screens...

  7. Expert Member
    Akos | | #9

    Side by side comparison of the 272.

    The clerestory window on the left is a hard coat low-e while the one on the right is the 272 triple pane. I find the 272 adds a slightly brown tinge to the light.

  8. alan72 | | #10

    I appreciate all the responses.

    I live in Detroit so I was able to visit the Comfortline factory in Toledo and the InLIne factory in Toronto. They both pultrude the fiberglass frames in their factories. Both use Cardinal glass. The factory was idle (mostly) at Comfortline. Inline was running - they said they run 24/6 or 24/7.

    Looks like they are comparable. I thought the opening and closing mechanisms were similar, but I wasn't comparing them side to side.

    Alpen look really nice - very pricey though -- out of my league.

    We are probably going to choose inline. Ethan, I appreciate your input - it was nice to here from someone with inline windows. We may choose some Tilt/turn windows - the hardware is what makes them expensive - from Germany.

    Here are our IGU choices:

    3mm Clear - Arg.- 3mm 180 [S3] - Arg.- 3mm 180 [S5]

    3 mm 272 [S2] - Arg - 3 mm Clear - Arg - 3 mm 180 [S5]

    3 mm 272 [S2] - Arg - 3 mm Clear - Arg - 3 mm 272 [S5]

    3 mm 366[S2] - Arg - 3 mm Clear - Arg - 3 mm 366[S5]

    We are trying to maximize (lower U-factors) and maximize our Vt - at least around our patio/backyard yard area. We will probably choose 272/180 option. A little more SHGC than I would like, but a pretty good Vt.

  9. Expert Member
    BILL WICHERS | | #11

    Cardinal generally only recommends one layer of the more aggressive coatings (272, 366). You’ll see in their datasheets that if you have, for example, a coating of 272 the “other” coating on the triple pane assembly will be 180. I suspect this is to keep things from getting too dark.

    Cardinal data sheets show no improvement in U factor for triple pane windows when going from 272 to 366, but you do lose on VT. You’re far enough north that solar gain is much less of an issue overall too. I had these same decisions to make (I’m approximately in clarkston, so maybe an hour north of Detroit), and ended up going with the “full width” 1-3/8” triple pane IGU with 180/180 and i89.

    Triple pane windows can get pretty dark with the more aggressive loE coatings. I would definitely look through some examples before making a final decision. I wanted to keep VT up around 62+% at center glass, and I didn’t worry about SHGC so the best U factor option for me ended up being two layers of 180 and i89 on the inside.


  10. RussMill | | #12

    Alpen service leaves something to be desired, at least in our case.

    1. cmaierhofer | | #13

      Hi Russell,

      I'm the Vice President of Business Development at Alpen, and I can't tell you how sorry I am to hear that you did not receive the highest quality of customer service that our company strives for and normally delivers. Our staff truly prides itself on a high level of responsive and consultative customer care, in addition to offering vast technical knowledge to help customers make the best decision possible. We work very hard to maintain a great reputation, so I'd love to talk to you personally about your experience and discuss any service issues you encountered so that we can improve! We appreciate your time and hope to hear from you very soon.
      Craig Maierhofer
      VP of Business Development

      1. RussMill | | #17

        Sure, I'll be glad to give you a call.


  11. Reid Baldwin | | #14

    We have Inline windows in our house, which was built in 2016. Most of our windows are casements. Our only complaint is that some of the plastic parts in the mechanism have broken. I asked them to send replacement parts for me to install myself, which they did. (I am waiting for warmer weather to try to replace the parts.) We also have two Inline sliding glass doors. One works great. The other one is a bit hard to open and close.

    1. Expert Member
      BILL WICHERS | | #16

      You might have a misaligned roller in that sliding door that is hard to open and close. Roller adjustment isn’t particularly difficult so you might want to try that to make your sliding door work a little better.


  12. cmaierhofer | | #15

    Relative to glazing questions on the thread, one of the glass strategies we often use with customers that you may want to consider (regardless of supplier selection) is to “tune” the window package to best optimize VT, U-value and SHGC. It is pretty common for us to use more than one glass package in a project to optimize those trade-offs - depending on orientation, customer preferences, exposure and other considerations relevant to that specific project. For instance, you may want to use a higher VT option on the north and east and a somewhat darker glass package (better SHGC solution) on the west and south. As long as there is no mixing of the glass types on the same elevation, there are no visual challenges. One word of caution, If you are in a high humidity environment (or maintain a high relatively high humidity level inside your home), be aware that the interior surface (4th surface of a dual pane or 6th surface of a triple pane) using Cardinal i89 can at times be a higher risk for interior condensation on the window surface as it works by reflecting heat back into the home, and has less heat absorption into the glass surface, which results in a lower surface temperature (better u-value but lower surface temperature) than even clear glass. We wish you the best of success in your window selection process, and would be happy to provide some glass combination samples for you to compare for educational purposes.

  13. onslow | | #18

    Allan, Not sure where you are relative to possible Alpen reps or factory. My rep was great and the factory responded to a screen issue promptly. I like their hardware and seals which I find very good. We have fixed, casement for egress and awning for rain weather air flow. Hardware is forever, so just consider carefully some of the feed back prior to my post.

    My choice of .24 SHGC was dictated by our very bright summer sun at 8000 feet. Even though the visible transmission is something around 47% the effect is not noticeable. If you are on water or have large snow filled vistas the reduction is nice to have. The tint of the coatings overall seem pretty neutral to me. The only awareness I have of the coatings is when I come inside with polarizing sunglasses on.

    If you do go for triple pane, consider the potential weight of the units. Two of our biggest units were triples and proved close to the practical man lifting limits during installation. Since Alpen has the film for the third layer, the units are probably a good bit less hefty than three full glass units. If all your units are smaller that won't be much of an issue.

    As for cost, the deciding factor for me was the ability to have a window delivered with argon to a location over 6,000 feet. Compared to the other major brands with similar features the up cost was not that much. Plus none would put argon in the units. I do have finish details and trims that pushed the costs beyond what I could have done, but like I said the argon fill was critical. I also support triple glazing for the lack of cold hole effect that double pane windows give. Our corner breakfast nook has 38x54 and 43x54 windows that I sit next to all winter with no discomfort.

  14. alan72 | | #19

    Thanks again for the robust discussion that came from this question.

    Ethan, Akos, and Reid - it's nice to hear from someone who owns Inline windows. We haven't ordered yet but we are probably going to this or next week. We are eliminating several functional windows and like using Tilt/Turns for the bedroom egress windows. I still don't have a price comparison between the Casements and the Tilt/turns. If we choose the Tilt/turns, I hope that we won't have mechanicals that break... When I visited the factory, they said the casement and awning mechanicals are all metal - no plastic parts. Reid, maybe this is changed from when you installed yours in 2016?

    Regarding the IGUs - I spend some time on the NFRC web site - I think its most useful (for me) for the U-factos and the SHGC. Whole unit Vt numbers aren't helpful - center of glass makes the most sense - knowing exactly which cardinal IGU each option is would be nice - I think I figured most of it out.

    More than likely we will choose -- 3 mm 272 [S2] - Arg - 3 mm Clear - Arg - 3 mm 180 [S5].
    It's more SGHC than I would like, but we have a large attached covered patio - my wife and I are concerned about the living room being too dark esp if the VT is low (if we chose 3 mm 366[S2] - Arg - 3 mm Clear - Arg - 3 mm 366[S5])... of course the window faces west...

    Anyways, thanks!

    1. Expert Member
      BILL WICHERS | | #20

      You could use 366 and 180 in the assembly instead of 366 and another 366. Cardinal data Typically shows one pane with an aggressive coating like 366 and the other with 180, which will let more visible light through. It’ll still be darker than the 272/180 combo though.


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