Insulation question and new construction…. thoughts?
托马斯·罗伯茨|Posted inEnergy Efficiency and Durabilityon
新建筑，我们正在做一个非通风的阁楼，以将HVAC管道保存在条件空间中，并在屋顶甲板上放有泡沫。来找出答案，我们可以以相同的价格将所有墙壁与所有墙壁与所有墙壁放置，这使我感到惊讶。这将使房屋变得狭窄，这将我想到“哪种机械通风”？房屋需要呼吸，并有很好的空气交换。
House是一个2层，将安装大约2700平方英尺的HVAC单元。最大的担忧是一个良好的通风系统。
想法？通风建议？我们在彭萨科拉（Pensacola），一个非常炎热潮湿的环境。
Thanks much in advance.
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答复
托马斯，
首先阅读本文：设计良好的通风系统。
在您的气候区域，您可能最终会获得中央粉丝集成的供应通风系统。
Two caveats:
1.确保您的承包商在室外气管上包括电动阻尼器，并确保您的系统包含空气循环器控制。
2. Make sure that your contractor knows how to commission the system. Air flow rates must be carefully measured and adjusted to avoid overventilation -- if you overventilate, you will invite too much humidity indoors.
托马斯，
You also should read this article://m.etiketa4.com/blogs/dept/musings/open-cell-spray-foam-and-damp-roof-sheathing。
由于您的气候，您可能需要重新考虑在屋顶护套上安装敞开的蜂窝泡沫。
史蒂夫，
Thomas said that he is planning to install "foam on the roof deck" for a new house. I assumed he meant "rigid foam above the roof sheathing" -- but perhaps he meant "spray foam under the roof sheathing."
他从未提到他是考虑为墙壁开放式喷雾泡沫还是闭孔喷雾泡沫。
猜猜我应该指定，在屋顶护套下打开细胞泡沫。墙壁将是开放式的细胞泡沫，关闭的墙壁将很棒，但我们确实有预算要面对。
托马斯，
显然史蒂夫猜对了。他是对的;你don't want to install open-cell spray foam on the underside of the roof sheathing. Closed-cell spray foam is a much safer choice.
以下是有关该主题的两篇文章的链接：
开孔喷雾泡沫和潮湿的屋顶护套
High Humidity in Unvented Conditioned Attics
有了两个HVAC单元，很难不超大它们，以至于它会影响舒适性和效率。请务必在指定设备之前，先在其上运行一项合格的第三方（专业工程师，Resnet Rater等）在其上运行激进的手册冷却和加热负荷计算。您在想热泵吗？带有AC线圈的燃气炉？包装单元？迷你切片？
Odds are pretty good that with 2 units covering 2700' of conditioned space that the design load of one of the units (or even both) will come in at 1-ton or smaller level, and many equipment lines start at 2 tons. A 1.5-3 ton multi-split (ducted or ducted, sized appropriately for the whole house load) would give you options of more zones, but could be reduced to two if desired even for the larger units.
感谢Dana，非常感谢。我对当地的HVAC人有很多信心。我研究了HVAC公司至少6个月。
I have great confidence in a number of HVAC companies to install the equipment well, but the list gets a lot shorter when it comes to sizing it accurately. YMMV (Hiring a third party professional engineer to run the load numbers is still my advice.)
马丁，感谢您的链接。我会和我们的建筑商一起定价屋顶的闭塞牢房。总是会大幅提高价格。余额将必须是开放的单元格或Bibbs，我敢说，以相同的价格，开放的单元比Bibbs更好。真正及时的文章，并为我们所在地区提供现场！
From my limited experience, there is a large cost difference (3x) between BIBs wall insulation and spray foam. If the prices are the same, one or both might be wrong. Cut rate foam is no value - neither is overpriced cellulose.
您已经死了正确的标记，您可以相信我在那儿做家务。
托马斯，
作为Dana建议的后续，您可能会发现，适当尺寸（和较小）的系统将涵盖使用HVAC工程师或Resnet Advisor作为手册J的成本。还要记住，准确的设计也很重要将在系统的生活中提供更多的舒适性和节能。
There are no local Resnet folks here or I would go that route. I'll look into finding a HVAC engineer though, the HVAC folks I've got are really pretty good but nothing like a double check. On insulation, what R values would the braintrust recommend and where? Roof deck I am going to shoot for R49 with a minimum of R38. Not sure about the outer walls.
Your HVAC engineer does not have to be local. I used David Butler at Optimal Building Solutions, and all his work was done via phone and email. He does a very aggressive Manual J, which is what you want.
杰出，非常感谢史蒂夫！
史蒂夫，您是否有OBS David Butler的联系信息？我快速看了Google，找不到他。谢谢 ！
@Thomas
http://optimalbuilding.com/about_us.php
非常感谢约翰，好看！