答复

1. GBA Editor
   马丁·霍拉迪（Martin Holladay）|May 13, 2015 08:16am|#1

   将要，
   Does your project have an architect? A designer? An energy consultant?

   这个问题很容易回答如果你德西gner or consultant were using energy modeling software to optimize the envelope design.

   An "American R-2.5 window" would be a window with a U-factor of 0.40. That's not very impressive. I'm not sure that you have researched all of the window alternatives. There are good windows available with better specs than U-0.40, but that are significantly less expensive than European windows with a U-factor of 0.10 -- let's call them "pretty good" windows.

2. 
   D Dorsett|May 13, 2015 08:34am|#2

   一个简单的电子表格热负载计算会告诉您每次更改的性能。基本计算是：

   U-factor x area x temperature difference= BTU per hour

   U因子相对于R值之间的关系是：

   U-factor= 1/(whole-assembly R)

   The U-factors of window assemblies are published. The U-factors of framed wall assemblies have to be calculated or estimated, since cavity insulation is only a fraction of the cross sectional area, and has a different R-value than the framing fraction of the area, and the continuous layers of wallboard, sheathing, siding, and insulating sheathing all have their own R-values that add into the total. A typical wood-sheathed 2x6 wall with R20 cavity fill comes in at about R13-R15 whole-wall depending on the actual framing fraction and the siding & sheathing types, etc. The R-value of any continuous exterior insulation gets added directly to the stackup. The 1" ZIP-R adds about R6 over a conventional OSB wall, so that brings the whole-wall up to about R20, but mid-winter performance will be less than that in an RI location due to the low-temperature characteristics of it's polyisocyanurate insulation layer- call it R18-R19, unless you put at least 2" of exterior rock wool or EPS on the exterior of the ZIP-R to keep the polyiso warm enough to keep it in it's higher-performance range.

   Upgrading the cavity insulation to a high R/inch insulation has remarkably little boost to the whole-wall performance due to the thermal bridging of the framing. (R-1,000,000 cavity fill only brings a 2x6 wall up to about R17 or so average performance after thermal bridging.) Using less expensive cavity fill and spending it on thicker insulating sheathing (that isn't thermally bridged by framing) is a far better value.

   Windows usually comprise much less total area than walls, and gaining wall-performance is generally cheaper than window performance, but it depends on where you're starting from, and what your goals are.

3. 
   Will Gerstmyer|May 13, 2015 08:47am|#3

   Martin,
   Perhaps you have some makers to suggest. As you know, many builders are in the Marvin/Pella/Andersen camp; so OK, let's call their products R-3 but I have heard that gases they use have already left the window before they leave the shop, so I certainly don't want to count on gases. I have researched a few American and Canadian window outfits that are in the R-5 to R-7 range but find them very uncommunicative, even with our window package of 50 windows! With the Euro decline, the premium for the R-10 versus the R-5 is only about 15%. An average operable is costing us $550 and fixed is down at $340 (and for the bigger sizes of doors and windows there is no premium at all even with the American standard bearers!). Of course, the interior and exterior casing adds a fair bit of labor to the equation.
   I am an architect, but old school, and would appreciate the skinny on energy modeling software. The client may be forced into funding an energy consultant but is loathe to spend. Again, my sense is that the weak points in the envelope are the concern, and I don't see any other than the windows. So, perhaps my question is more conceptual in nature: Why build an R-40 wall if your windows are only R-3 and at ~30% of the wall will suck out all the heat; Why isn't more R-equality between wall and window a better way to reduce heat loss? Thanks, Will

4. 
   Will Gerstmyer|May 13, 2015 08:59am|#4

   Dorsett,
   感谢您对外部与空腔绝缘材料的观察 - 说得很好。同样，我对物理学的理解是，热量总是会热身它可以找到的最冷的物体 - 这是每个房间中的2或3个窗户，而不是墙壁，或者是按比例的，某些热量会寻找墙壁，但是最终，墙壁变得相对温暖，以至于热量会迁移到窗户上。在那里，损失是最大的，与更好的绝缘墙相比，窗户永远不会达到稳定状态，因此热量不断向这些位置移动。因此，您的最后一句话的确是一个问题：如果我们的窗户通常是任何房间中外墙的25％（这不是很少的），并且我们的外部绝缘材料可能被限制在3“，也许是4”，Don'从概念上讲，我们想将钱分配给更好的窗口？谢谢，威尔

5. GBA Editor
   马丁·霍拉迪（Martin Holladay）|May 13, 2015 11:34am|#5

   将要，
   The triple-glazed windows sold by范式窗口据说相对负担得起。但是，我从来没有定价它们。

   When it comes to European windows, Intus is known for low prices.

   GBA读者拥有比我更多的窗户购买体验的读者可能会在这里提出建议。

6. Expert Member
   Dana Dorsett|May 13, 2015 11:45am|＃6

   Correcting my typo- with R-million cavity fill you'd be at about R27, not R17... (With 5.5" of R6/inch closed cell foam you'd be at about R17.)

   举一个简单的例子 - 假设您有一个200平方英尺的房间，带有30平方英尺的U0.30窗口和100平方英尺的R20（整墙= U0.05）墙。对于各种温度差，窗户丢失了：

   U0.30 x 30 square feet= 9 BTU/hr

   对于每一定程度的温度差，墙都会丢失：

   U0.05 x 100ssquare feet = 5 BTU/hr

   Combined losses are then 14 BTU/hr per degree-F.

   If you spend a lot of money on U0.10 windows you reduce that 9 BTU/hr to 3 BTU/hr per degree F, a reduction of 6 BTU/hr-f per degree, bringing the total down to 8 BTU/hr per degree-F.

   显然，您无法将墙壁的5 BTU/HR-F热量损失减少6 BTU/HR-F，但是与直接进入U-0.10窗口相比，有一些实现相同热负荷的方法更便宜。例如：

   Reducing the size of the window by 1/3 would take 3 BTU/hr off the window losses, making the window losses 6 BTU/hr-F, but adds 0.5 BTU/hr to wall losses since it's now 110' of wall, not 100'. That's a net reduction of 2.5 BTU/hr-F.

   Using U0.20 windows instead of U0.30 is still a lot cheaper than U0.10 windows, and would cut the 6 BTU/hr-F window losses to 4 BTU/hr-F, a net reduction of 2 BTU/hr-F for the windows.

   So now we're at a 4.5 BTU/hr-F reduction without changing the wall stackup at all and have a combined load of 10 BTU/hr-F.

   要使剩余的2 BTU/HR-F减少相等的改进，与对U0.10的窗户进行改进相同。110'墙的U因子始于U0.05，导致5.5 BTU/HR-F损失。要将其达到3.5 BTU/HR-F的U因子为3.5 BTU/HR-F/100'= 0.032，这是1/U0.032 = R31的整个Wall-R

   通过添加R11额外的外护套可以实现。

   So the financial trade off becomes the cost of 30' of U-0.10 window vs. the additional 110' of R11 insulation (and the additional 10' of ZIP-R, which may be zero, since it comes out of the window-cut scrappage) + the cost of 20' of U0.20 windows over 30' of U0.30 window.

   For making these calculations easier a free download (courtesy of the US taxpayer) of the BeOpt tool is worth it, since you can then and play "what if" games based on real or estimated costs of different configurations, and get a much better handle on the where the $/performance trade-offs lie at any chosen performance level. See:

   https://beopt.nrel.gov/

7. 
   Dan Kolbert|May 13, 2015 12:30pm|＃7

   Intus Windows确实是一笔不错的选择。他们的基本型号UPVC与木马具有竞争力。

   And I agree w/ Martin that an energy modeler seems like a critical partner here. You're making huge and expensive decisions with very little data. And Dana's points about other ways to skin the cat are excellent. you can also think about using fixed units (both for price and performance) in some areas.

8. 
   Charlie Sullivan|May 13, 2015 01:21pm|＃8

   Rather than going all out on either, you are likely to do best with "pretty good" on both windows and walls. That might mean a triple-pane low-e argon window, but almost surely not a krypton fill gas which is where the U 0.1 values come from.

   For North American windows I recommend checking out Loewen (canadian) for great aesthetics and quality as well as performance at reasonable up to outrageous prices (if you go for their fanciest finishes), or Comfortline from FiberFrame for great performance at lower prices. I speak from experience with Loewen but only quotes from Fiberframe.

   As Dana illustrates, calculating the performance difference is not hard. What's harder is calculating the cost difference, particularly for wall construction.

9. Expert Member
   Dana Dorsett|2015年5月13日下午2:30|＃9

   作为一般规则,性能超群的窗户没有的t needed for most energy use or peak load goals unless you need/want a lot of window area, and cutting less window area into the wall adds effectively zero to the wall costs, since the cut out is usually scrap.

   While 15% window/floor area is typical, it's not a code requirement, and not always desirable. You don't need anything like that much window for daylighting purposes, and that much window area leads to uncomfortably high solar gains in some rooms.

   Huber recommends AGAINST installing exterior foam over ZIP-R, since there is then a moisture-trap potential at the OSB layer. Using rigid rock wool rather than foam eliminates that as an issue, but if you DO go with foam, use a crinkle type housewrap (eg. Tyvek DrainWrap) between the foam & ZIP-R for faster drainage and a partial capillary break.

10. 
    Will Gerstmyer|May 13, 2015 02:58pm|#10

    ％窗口/地板区域是一个很好的措施吗？我认为，到外墙区域的百分比窗口是更好地说明一个人是否推出过多的玻璃。（使用后一个量规，我们可以轻松进行基准测试，因为我们的机构项目在大约40个项目中平均为29％）。
    Forgive my ignorance, but if you utilize Zip System are you still looking at OSB and housewrap?

11. GBA Editor
    马丁·霍拉迪（Martin Holladay）|2015年5月13日下午03:05|#11

    将要，
    Zip System sheathing is a type of OSB manufactured by Huber. If the OSB seams are properly taped with Zip System tape, Huber says that you don't need housewrap. Many builders who use the Zip System sheathing use housewrap anyway, because housewrap is easier to integrate with window and door flashing.

    More details here:All About Water-Resistive Barriers.

12. 
    Peter L|May 13, 2015 07:11pm|#12

    将要，

    I would go to the Intus website and find the nearest dealer rep and give them your window schedule. Price it out for the white PVC triple pane windows and you will be pleasantly surprised that the pricing will beat out or match most dual pane windows.

    As an architect you know that house design is also about comfort. Triple pane windows provide superior comfort and one can sit next to a window without feeling a draft or convection. Plus they are quieter than dual pane.

13. 
    Dan Kolbert|May 13, 2015 09:52pm|#13

    Performance Building Supply -http://performancebuildingsupply.com

    与Alba或Jason交谈。

14. Expert Member
    Dana Dorsett|May 14, 2015 05:48pm|#14

    Will- regarding post #10:

    With ZIP-R the OSB is factory laminated to the polyiso, and has a WRB rated exterior surface coating, which works just fine if you're mounting your windows "innie" style, and adding rigid rock wool to the exterior, not foam. If you use exterior foam and innie windows you need to provide a capillary break between the ZIP-R and foam and some drain space, which is where the crinkled housewrap become important. Even though the exterior finish of the ZIP-R is a WRB, the surface tension of liquid water will trap it between the foam & ZIP, and some amount will eventually end up in the ZIP, taking forever to dry through the foam.

    干燥速率通过~ 30烫岩棉是一种排序r of magnitude faster than an inch of unfaced Type-II EPS, and more than 25x faster than an inch of XPS. And rock wool would mildly wick moisture away from the ZIP, whereas EPS or XPS would not wick at all, leaving vapor diffusion as the only mechanism for getting the moisture off the ZIP after a bulk water incursion. Crinkled housewraps allow gravity to purge the majority of the inundation, as well as a tiny amount of air transport out. Gravity would also take care of a lot of liquid moisture in the rock wool case too, as much or more than crinkled housewrap.

    如果安装窗户“ Outie”，则需要在岩羊毛或泡沫外部的房屋包上，因为窗户闪烁将散装水引导到其他绝缘的外部。

    Zip-R不需要另一层OSB。

    Window / floor ratios are a commonly used metric in the residential housing biz, even though window/wall ratios are more relevant from a heating & cooling load calculation point of view. At 15% window/floor ratio is about average. Codes specify minimum window areas for daylighting & egress purposes, and those are usually enforced. Some codes specify maximum window / wall ratios before the room has to be engineered on a total thermal performance basis, but those are often ignored, especially when there's a nice view to be taken in. (Something like that happened on an addition to my home prior to my tenure- the newest rooms are the lossiest. It really needed higher performance windows or less window, but correcting that is an expensive proposition- there is still lower hanging fruit elsewhere.)

15. 
    Will Gerstmyer|May 18, 2015 02:29pm|#15

    对于那些提到Intus的人
    Thank you, but EAS-USA is better, unless the flange offered by Intus is something really special. The least expensive Intus line (Arcade) is $26/SF for fixed and $40/SF for operable, and is R-6.7. The Schuco 182 window at EAS is R-10 and beats those prices. Plus, the prices I have from EAS include a Mahogany foil on the interior which is another premium on the Intus. Thanks, Will

16. 
    Peter L|May 19, 2015 02:48am|#16

    将要，

    I believe you have misrepresented the data. The Schuco 182 window you referenced is NOT an R-10 window. The REAL whole window value is around R 6.5 - R 7.0

    验证NFRC＃的s，您会发现自己的结论不正确。我进入了NFRC网站，无法找到欧洲建筑供应，Schuco或Makrowin Windows作为参与成员。基于此，窗口未经过测试，也未通过NFRC认证。Intus Windows在NFRC网站上列出，它们是参与成员，并已在Windows中转动通过NFRC进行测试和认证。通常发布的欧洲价值不是苹果与美国NFRC＃的比较。

    As far as posting square footage prices of Intus. Those numbers are not accurate either. I've seen the prices and a lot of the cost depends on options. I've seen prices as low at $15 per square foot for Intus' triple pane uPVC fixed windows. So throwing out #'s is not fair because of the options that are available and one doesn't know if you are comparing apples with apples.

    If you have the NFRC #'s of the EAS/Schuco Windows you are referencing that achieve a whole window R-10 NFRC rating, please provide the NFRC link showing the ratings. I could not locate any NFRC testing for the window manufacturer you quoted.