John There's 30 years of research reports on this. Start off going to the Florida Solar Energy Center's website. The essence of a radiant barrier is that it EMITS a very small percentage of the heat that it absorbed. This is why you saw foil wrapping on the Lunar Excursion Module that landed on the moon - the foil wrap limited the amount of heat that would escape the spacecraft. Net-net is that RBs reduce solar radiation heating of an attic by about 12% to 25% - roughly equal to adding R-19 of extra insulation to the rood system in the summer, about R-4 in the winter.
The Houston Homes had HVAC in uncondtioned attics and Code minumum R-value at the ceiling. I believe that HVAC does NOT belong in unconditioned attics ... AND that we should be building homes with MUCH more than Code minimum R-values.
I can't imagine how a Radiant barrier roof sheathing could save energy during the heating season.
John, Radiant barriers work -- they just cost more and are less effective than other methods of insulation. The only application that makes sense (sort of) is to install radiant barrier sheathing during new construction for a house with ductwork in a vented unconditioned attic. (Even better, of course, would be putting the ductwork inside the conditioned envelope of the house, where it belongs.)
In addition to the link provided by John Klingel --Radiant Barriers: A Solution in Search of a Problem-- and the link to the John Straube podcast provided by John Brooks -- you might also want to read a couple of articles about so-called "insulating" paint:
Thank you all for your answers. My daughter and I ran a simple experiment as we wanted to know if white paint would serve the same purpose as foil? We built 2 model doll houses with detachable roofs, one was regular osb and the other was tech shield. We put them both under a 100 watt light to see what the radiant barrier did. The results were the radiant barrier did as much as the ordinary osb.
So thank you all again...our experiment says we have all been duped into spending money on something that doesn't work. 新年快乐 john
Radiant barrier on roof sheeting causes more heat in hot climates by trapping it inside the attic for it too be effective it needs to be placed on top of the insulation above the ceiling then it keeps the heat from transfering as quickly to the insulation. Radiant barrier on or below the roof sheeting makes zero sense unless you have complete soffit vents and a roof ridge vent installed the full length of the roof so the air can move between the space between the sheeting and rafters. Then it will keep the attic cooler but again far more effective to put on top of insulation. The issues with dust are not as much of an issue now with using the reflective film vs the aluminum. the film is a ton more reflective and if you want go clean the dust off once a year.
答复
John
There's 30 years of research reports on this. Start off going to the Florida Solar Energy Center's website. The essence of a radiant barrier is that it EMITS a very small percentage of the heat that it absorbed. This is why you saw foil wrapping on the Lunar Excursion Module that landed on the moon - the foil wrap limited the amount of heat that would escape the spacecraft. Net-net is that RBs reduce solar radiation heating of an attic by about 12% to 25% - roughly equal to adding R-19 of extra insulation to the rood system in the summer, about R-4 in the winter.
我不说“ nuttin”，因为上次我搞砸了。但是，在这里阅读，看看马丁怎么说。也在这里搜索其他信息。我认为本文提到了NASA参考。
//m.etiketa4.com/blogs/dept/musings/radiant-barriers-barriers-solution-search-problem
加拿大抵押与住房公司（CMHC）进行了4个测试房屋，每个测试房屋都有不同的地板绝缘层；挤出的聚苯乙烯，聚异氰尿素，气泡箔和无绝缘控制。气泡箔看起来好像没有隔热材料。有一个PDF，他们的发现漂浮在某个地方，搜索，我敢肯定您会发现它。根据我收集的辐射屏障，需要空气差距和清洁的表面才能有效工作。用于泡沫聚苯乙烯的新型辐射屏障添加剂（Neopor）不需要气隙。
这是关于辐射障碍的一些垃圾谈话：http://www.healthyheating.com/Page%2055/Page_55_o_bldg_sys.htm
我认为约翰·斯特劳伯（John Straube）很好地解释了为什么“航天器”类比在这里并不相关：
//m.etiketa4.com/blogs/dept/building-science/how-heat-moves-through-homes-building-science-podcast
如果您想要数据...
迈克尔·布拉斯尼克（Michael Blasnik）对休斯顿的房屋进行了一项大型研究，其辐射屏障屋顶护套，报告的年度冷却减少了约180 kWh。
The Houston Homes had HVAC in uncondtioned attics and Code minumum R-value at the ceiling.
I believe that HVAC does NOT belong in unconditioned attics ...
AND that we should be building homes with MUCH more than Code minimum R-values.
I can't imagine how a Radiant barrier roof sheathing could save energy during the heating season.
John,
Radiant barriers work -- they just cost more and are less effective than other methods of insulation. The only application that makes sense (sort of) is to install radiant barrier sheathing during new construction for a house with ductwork in a vented unconditioned attic. (Even better, of course, would be putting the ductwork inside the conditioned envelope of the house, where it belongs.)
In addition to the link provided by John Klingel --Radiant Barriers: A Solution in Search of a Problem-- and the link to the John Straube podcast provided by John Brooks -- you might also want to read a couple of articles about so-called "insulating" paint:
“绝缘”油漆商人骗子可骗的房主
An ‘Insulating’ Paint Salesman Is Tripped Up By His Own Product
(Thanks, John Klingel and John Brooks, for providing the links.)
辐射屏障的应用有限。佛罗里达太阳能研究表明，随着您增加绝缘层，辐射屏障的益处会减少。如果您正在建造并可以在应用屏障的情况下使用护套，那么这可能是值得的。如果您正在研究改造，那么可能不值得。如果您家的阁楼价值低于R20，那么您将获得很多好处。但是，如果您的房屋不足，那么空气密封和隔离是有意义的。随着R值接近R30，好处要小得多。将R值提高到38或更高，而RB几乎没有值。最好将这笔钱花在可以节省更多钱的东西上。
Thank you all for your answers. My daughter and I ran a simple experiment as we wanted to know if white paint would serve the same purpose as foil? We built 2 model doll houses with detachable roofs, one was regular osb and the other was tech shield. We put them both under a 100 watt light to see what the radiant barrier did. The results were the radiant barrier did as much as the ordinary osb.
So thank you all again...our experiment says we have all been duped into spending money on something that doesn't work.
新年快乐
john
Radiant barrier on roof sheeting causes more heat in hot climates by trapping it inside the attic for it too be effective it needs to be placed on top of the insulation above the ceiling then it keeps the heat from transfering as quickly to the insulation. Radiant barrier on or below the roof sheeting makes zero sense unless you have complete soffit vents and a roof ridge vent installed the full length of the roof so the air can move between the space between the sheeting and rafters. Then it will keep the attic cooler but again far more effective to put on top of insulation. The issues with dust are not as much of an issue now with using the reflective film vs the aluminum. the film is a ton more reflective and if you want go clean the dust off once a year.
格雷格·布朗... Rediculous, no soup for you. The dust is a factor. Who the H*** is going to dust their insulation system annually in their attic. LOL
不过，享受周末，请在这个美丽的蓝色球上玩一些戏。