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Community and Q&A

Selecting Contractor Grade Windows

spb2015 | Posted in GBA Pro Help on

I am comparing windows for a house I am building in northern Virginia (Zone 4A). My contractor has recommended Harvey Windows, and possibly HiMark Windows as options. In terms of budget, vinyl windows are my only choice at this time. 

I have attempted to look at windows that have extremely low air infiltration and have stuck with picture or casement windows as well. In some places, I’ll opt for triple pane, but budget dictates double in most. 

1. When looking at options for budget friendly windows, is there an order of importance of technical specifications when selecting windows? The technical sheet provided lists a few technical details including: 
1. Air infiltration,
2. Water resistance,
3. Structural test pressure, 
4. DP rating, and 
5. Structural rating. 

2. What are the minimum technical standards to look for? 

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  1. user-2310254 | | #1

    You might want to get a price on Andersen 100 Series composite windows. I had them in my last house. The composite material is likely to expand and contract less than a PVC window.

    Air infiltration is important since you would expect casements and sliders to be pretty tight to begin with.

    The most critical issue though is proper installation. See for details.

  2. ssnellings | | #2

    Taking care while selecting windows is an important step of the process, however what I don't see is an evaluation of your installer and install detail. An excellent window poorly installed can be a nightmare.

    I raise this as an issue because a previous post of yours involving exterior wall assembly decisions revolving around two assemblies that have out-board roxul and a rainscreen assembly. You don't have a standard wall, so the window install may also differ from standard (hard to know without drawings).

  3. GBA Editor
    Brian Pontolilo | | #3

    Hi Samuel,

    The key is to get the lowest U-factor your budget will allow with the right solar heat gain coefficient for your climate and house. Air leakage is an important number too, though it's not going to make or break the air tightness of your house. Other details, including, as Steve points out, the right installation details, and many other things are more important for air sealing. As Emily Mottram told me when I was working on this article, houses have achieved passive house levels of air tightness with double hung windows. Anyway, this may be helpful: Buying Windows.

  4. spb2015 | | #4

    Thank you all for your comments and advice! I’m documenting my experience and hopefully will provide a write up in the future of the entire design and build of my home.

    I’ve narrowed the windows to Okna 800 or Starmark series, Soft-lite Elements, or Provia windows. From the quotes I’ve gotten so far, these premium vinyl/composite windows make the quotes I’ve gotten Marvin, Pella, Andersen, and Jeld-Wen look ludicrous in terms of cost. Counting windows with multiple milled units, my house will have around 45 windows. This requires extremely low air infiltration from each window since the difference between .01 vs .1 per window adds up significantly. The windows will be either picture/fixed or casement for operating windows. Each of these windows are made with uPVC or a APC material, robust reinforced frames, and air infiltration of .03 or less. In fact most have an air infiltration of .01.

    A little background on the sheathing. I’ve decided to use 3/4” CDX plywood as the sheathing. All seams and nail heads will be air sealed with a 100% silicone caulk from Tremco, Spectrem 1 (20 year warranty). The sill connection will be air sealed with a gasket and utilizing Tremco’s Dymonic 100 (10 year warranty) Interestingly, after discussions with Tremco’s technical department, they recommend a urethane sealant for concrete / foundation sealants, and a 100% silicone based sealant for the sheathing walls. Silicone based sealants don’t get along well with concrete currently. Or at least their products.

    A quick tangent. I’m not convinced that even the best acrylic style tapes will last longer than a good silicone based caulk/sealant for sheathing. I like the idea of Tremco’s sealants since they’re upfront on their warranty length. I have found finding warranty time lengths for tapes to be nonexistent from my current research.

    The next step is the installation of the window. before adding 2” of comfortboard 80. The initial plan is to fully flash all rough openings with a liquid flash. Then, follow the window install guides provided to flash the windows to integrate the windows with the house wrap (looking at Kingspan Greenguard C2000). I’ve taken the inspiration from this video from Matt Risinger. At each stage, the goal it to integrate the flashing so there is redundancy at all rough openings.

    As a involved future homeowner, my limitation is knowledge gleaned from resources like Greenbuilding Advisor. One thing I’ve found is not to rush and to work on getting the details right, and be flexible! That means if some of my details I’ve mentioned aren’t right or there is a better cost effective way I don’t know of, I am here to learn and be corrected. The one thing I’m sure of is that I don’t know much!

    1. ssnellings | | #5

      I don't see anything critically wrong with any of your choices. I would like to call out two moments where I think you've been taken in by a sales pitch.

      First, if you are finding the quoted price difference between your selected windows and other brands to be "ludicrous", that's a moment to review the quotes and figure out why they may be so different. If you can't figure out why there is a large price difference, that's cause to keep digging. I also don't think the term "premium vinyl/composite" means anything, in the same way that Marvin names their window lines "Signature" and "Elevate" and "Essential" - those names also don't really mean anything, they are just a short-hand for a collection of traits. I worry when I see someone call a brand or a product "premium" in the course of normal conversation, as it's a meaningless adjective.

      Second, Tremco's products are fine. However, you note that their warranty is what helps seal the deal. Tremco's warranty covers defect in materials only, it does not cover any defect as part of applying their materials to a particular purpose. The only damages that would be covered under their warranty is the cost of a replacement tube of sealant. To confirm this make a search for their product data sheets which include the warranty language. There isn't a huge difference between no warranty and a warranty that just provides a replacement tube of product.

      All the best, I'm sure you're discovering that it's both easy and difficult to get the details right!

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