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Fiberglass window choices for new build in Colorado

Pinoli | Posted in General Questions on

Hi everyone,

We are building a new home in Colorado, 7100 ft, south facing, energy efficient, single story. That is the short story. We are only considering fiberglass windows. The choices are Alpen 525, Marvin Integrity, Miguard Ultra and new to list Kolbe Forgent. In terms of energy efficiency: U, SHGC, VT the best is Alpen, made just outside of Denver, but no local vendor. The rest have local vendors for support.

My question is two fold, has anyone feedback on any of these windows? And what do you think of the newly release Kolbe? The Kolbe price is sweet but the product is NEW,,which makes me hesitant

Comments all welcome. Lydia

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  1. thrifttrust | | #1

    I'm looking for fiberglass windows as well. I hadn't heard of Kolbe, but their cutaway frame looks impressive. Fiberglass frames usually have simple tubular sections. Alpin fills theirs with foam to get high thermal performance. Kolbe's have intricate multi chambered sections similar to high quality vinyl windows. This design should give good thermal performance without foam. I don't know how they make these frames. Fiberglass traditionally can't be formed in thin intricate sections. I'm going to check them out. Unlike other window manufacturers Alpin has a suspended plastic film instead of glass in the center of their triple glazed units. I'm not sure if that's a plus or minus.

    Douglas Higden

  2. Stockwell | | #2

    I did a long search for fiberglass windows as well. I liked the Alpen window, but it was significantly more expensive than the others. The Kolbe wasn't available when I was looking, but appears to use fiberglass with some other resin to form those chambers. U-factors look better than most, but not up to Alpen levels. Milguard wasn't available in my area. The Marvin Integrity all-fiberglass version was only available in double pane and felt light and cheap to me. I stumbled across Enerlux windows which is what I am going with. They were priced affordably, built like tanks and had great numbers. The only issue is no local dealers and relatively new company. Make sure to look at the Canadian suppliers as well.

  3. brp_nh | | #3

    We have Alpen 525 windows in our house in NH (climate zone 6) and have been happy with them. We went with them over Marvin Integrity because the specs are better and easily met Energy Star requirements for our build.

  4. mikaturner | | #4

    We installed Alpen windows with vinyl frames (Huntington SP) in our home here in Minnesota (Climate zone 4) and they have been great. They were significantly cheaper and higher U value than Marvin's. Our general building contractor was able to do the install, so we purchased directly from Alpen.

  5. user-6990904 | | #5

    Original poster here, thanks for the feedback. Am curious on those with new builds, our contractor mentioned the importance of using a local vendor who supports the windows as they need adjustments when the build is complete.

    Any comments appreciated, Lydia

  6. brp_nh | | #6

    The Alpen windows come with an air reservoir and breathing tube, to allow the windows to adjust to local conditions. The adjustment (cutting & crimping) after installation is easily DIY. Look under the installation documents here:

    No adjustments other than that. Our Alpen dealer is 2+ hours away, but it hasn't been an issue because we haven't needed support.

  7. Stockwell | | #7

    I am not worried about no local vendor. In my current house, the vendor went belly up three years after we moved in. Anderson has sent third parties out for the two problems that we have had over the years. Warranties are a crock most of the time anyway. In our case, their vinyl clad jamb fails. The vinyl separates from the underlying wood. Yes they will replace the jambs, but no they will not pay for labor. So, do i want to pull all the trim from 16 windows, replace the jambs, replace the trim, recaulk and repaint? I am not sure what adjustments your contractor is talking about. If installed correctly in a properly framed opening, the windows should perform as intended.

  8. CMObuilds | | #8

    The comment about the Kolbe frame cutaway is interesting. Would it be possible to add some fiberglass to the vinyl and call it a fiberglass hybrid?

    Kolbes description is "fiberglass hydrid and uv stable polymer."

    *I bring this up because as soon as they discontinued their Latitude vinyl window line which had its own plant, the Forgent series appeared making me wonder if they are using the same equipment.

  9. onslow | | #9

    Ms. Segal,

    Just chipping in to say that I am at 8000' on the western slope over five hours from Denver and still chose the Alpen. It is wise not to use vinyl windows due to the extreme sun load and temperature swings. The expansion of fiberglass to glass seems well balanced and the expansion differences between window and stucco has been very acceptable as well. I suspect the few gaps that appeared after the first year were more related to foam shrinkage.

    I don't know if it is fair to name the dealer we used on the forum, but he was excellent and the only annoying part of the windows is hiding the little capillary tubes after installation. It is a bit tricky to release the strip enough to stuff them out of sight. I have a tool suggestion that I prefer over the company's choice based on having to hide more than 30 of them. The dealer being far away was and has not been an issue for me.

    More important than the tube issue is the fact that Alpen windows do have argon gas (or krypton) which at the time I ordered windows, no one else would put in their units. Marvin wouldn't ship to over 5000' with gas, Sierra Pacific only shipped to Colorado with air, and I am pretty sure Integrity wouldn't do argon over 5000' either. The dealer for Marvin tried to tell me that the argon was overrated and would all leak out anyway. I doubt that very much and the performance of the Alpen windows has been excellent. And in case anyone notices I post a lot about my windows - no I'm not a secret plant, I just really like my windows. I have had or installed other brands that literally left me cold.

    Kolbe windows are from Wisconsin so I doubt they are use to altitude settings and I would be careful of hybrid technology that is new. If it really is glass-filled thermoplastic material they might well be the next big thing, but time is a great leveler. Becoming the high altitude guinea pig might not be what you are interested in.

  10. user-6990904 | | #10

    Original poster here, Thanks for all the feedback.

    No question my preference is Alpen for the energy efficiency numbers. They are though about 30 percent more money. In general the difference in U values is Alpen 0.2 and the rest are on average 0.3.

    Two questions..
    1.Is the difference in U values enough to warrant the additional upfront dollars?
    2.And will we be more comfortable with Alpen?

    Also will post this as a new question..lydia

    1. PBP1 | | #13

      Pella Impervia has U values for sliders at 0.25 (insulated frames) and others at 0.21 (maybe some less), some say quality of Integrity might be better but Impervia seems fine - have had them for three years - some minor nits but nothing major (yet).

  11. KFleischman | | #11

    Hi Lydia, We have had many major issues with the Alpen windows including wrinkling in the interior of the windows. We live in Colorado too and these products do not hold up. Please watch this video to see some of the issues we are having.

    1. nishche | | #12

      We live in CO and are also trying to decide between Alpen + Marvin (Essential) line. Would you be willing to chat with me about your experience with Alpen? Thanks in advance!

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