Radiant Barrier -Reduce the heat or coolness of your attic by as much as 50%
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- เผยแพร่เมื่อ 26 ก.ค. 2012
- Sacramento Brower Mechanical Energy Upgrade California
"HeatBloc-Ultra radiant attic barrier coating is a water-based, low-emissivity (low-e) product which reflects up to 75% of radiant energy. Designed to be sprayed on the underside of the roof deck, ridge and gable ends, it is breathable and will not increase attic moisture.
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Excellent video! Thank you very much for it.
Best explanation on the web
is it effective at all if you are only able to install it in part of the attic?
where did you find this ancient video? What was it shot in - 360i?
So does that mean this type of barrier can only prevent the attic from getting any hotter than the ambient air temp correct?
My. White steal roof works well to where I can stand to work in my attic Even when it's 100 out.
Seriously? That's amazing!! By the way, is your roof insulated as well?
Nah
If we use a pvc ceiling on attic space heat will goes up or down?
What is the best celing can use a domestic house?
Can Explain Attic ventilation system?
Good content. The shade example does not factor dew points for man.
very informative but I don't see how this can't be bad for the shingles...the reflected heat has to to somewhere and that somewhere is...well, the shingles!
Paint your roof with Roofguard 700 about every other year with a roller and never worry about a new roof again.
1) A low-e surface also does not 'stop' the heat, it reduces the rate of radiation (emission).
2) folks should be keeping HVAC out of unconditioned attics
3) the savings on low-e barriers are greatest when there is no insulation at all. Once you add significant insulation (such as code mins) the effects of a radiant barrier becomes quite small as a percentage of effective heat resistance. In this way, the suggestion that 80% of heat gain is radiant is used disingenuously. You're better off adding more insulation. Of course if the low-e coating comes without an up-charge, certainly go for it!
All companies spin their products ('by as much as 50%'...), but this video makes important points about the need to address each of radiant, convective and conductive heat transfer. I don't think the 80% heat gain point is disingenuous so much as contextual. They do mention southern US climates. Radiant barriers are going to make a bigger contribution to cooling in hotter climates/summer than in cooler environments. Adding more bulk in very hot places is not cost-effective and here in Australia we allow the industry to rate the R-value of bulk insulation through tests conducted at 30 degrees celsius. We don't require the industry to prove it remains effective in hotter weather when it just heats up in the morning and then releases heat into living spaces the rest of the day. You are not better off just adding more bulk insulation in hotter climates if your aim is cooling. A moderate amount of bulk with a radiant barrier will be better. Mainstream industry makes big bucks on bulk and don't want people realising a cheap radiant barrier makes a bigger difference than more bulk for many applications.
When the radiant barrier reflects the heat back to the roof tiles, can they not become too hot? My are already hot like glowing metal. .. without reflexive radiant barrier.
I've read in another video that a reflective barrier increased the temperature by only about 5 degrees. However, to my knowledge no manufacturer of shingles has ever voided or denied their warranty because of use of a reflective heat barrier.
I believe the doe did a real test and it was a 30% reduction... Something, but not as hyped up as some say.
Reflection of 50% visible light by white roof means also 50% heat reduction - or only visible light reflection?
The heat you feel is infrared. As a bullshit guess, stopping 50% visible light probably stops 2% infrared.
@@seinfan9 no. Its all energy on a spectrum. Forget about the 3 distinctions of visible, UV, and IR for a moment and just consider how much total energy is rejected by a roof.
@@seinfan9 Roofguard 700 brought my roof from about 145 degrees to about 5 degrees above ambient temperature. I can now sit on my roof summer midday without getting burned. It's just warm. Those statements are incorrect.
Why is this product recommended on the underside of the roof deck?
I you're doing a tear-off down to the wood roof deck, can you apply to the top of the roof deck
without affecting effectiveness or longevity?
I would assume you can, but the video talks like it's selling a retrofit for the product without having to go to the expense of reroofing. It's basically using an aluminized paint, similar to those emergency blankets, to reflect the radiant heat.
In fact if you're that interested, there are foil lined roof liners/water barriers and insulation panels that do the same job as what this video talks about. It's just that this is an OLD video before those products came out. Rockwool, zip, etc.
No, there has to be an air gap on one side of a reflective barrier.
@@percyfaith11 That just makes it even easier. there's a variety of aluminized plastic sheets dubbed "thermal Barriers" you can staple up to the rafters.
@@zetsumeinaito yup 👍
Great video.. but where can I buy this product or get a good amount to paint my attic ?
Don't PAINT it. Install it. Shiny metal foil, shiny side DOWN. Use a staple gun, attaching the radiant barrier to the underside of wood. Remember to facilitate some convective air flow from eave vents to ridge vents.
@@johnbecich9540 How to define "some convective air flow"? My roof tiles have a round opening of a half circle of 4 cm where air can flow. Is this enough or when I construct some further flow with a small gap from below to ridge vents?
@@johnbecich9540 Shiny metal foil, --- like a aluminium foil?
shiny side DOWN? Do you not mean the shiny side in direction to the roof tiles? In order to reflect radiation back?
@0:37 Nice math.
Radiant barrier R factor
You mean reflectivity or emissivity (about 95% for both) Radiant barrier stops radiant transmission, not conductive like insulation does.
That's incorrect. A white roof will make a dramatic difference in heat gain. My attic used to be about 145 degree F during the summer days. Now with several coatings of Roofguard 700, not only do I have a forever roof, but my attic never gets above 5 degrees ambient temperature.
Did you spryed it? and how many times?
@@rosauraelias77 I used a roller with a 3/4" nap and roller pole to push the sealer uphill.
@@rosauraelias77 4 layers the first time. That completely sealed a dead roof. $400 vs $4,000.
Do I need to roller and push the sealer in the attic ? Not out the arctic? Thank you
@@rosauraelias77 ???? You're using RoofGuard 700 on the shingles themselves, pushing the coating upwards underneath the shingles to lay them down. I have decided to do this annually to get a thicker coat on the roof. $100 per year keeps hundreds out of my electric bill. If I'm not at home my electric bill is about $100 per month compared to my neighbors which is over twice that amount and 1/3rd the size of the house.
A radiant barrier will drop the attic temperature at MOST, 4 DEGREES F!!!!!!
This video is unwatchable...within the first 45 seconds there is a glaring mathematical error.
“White roof makes no difference”. You are lying or misinformed, makes me think you’re a Scammer salesman