Practice English Speaking&Listening with: Radiant Barrier Paint vs. Foil - What's The Difference?

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In this video I'm gonna compare radiant barrier foil to radiant barrier paint.

Now in full disclosure: obviously as the owner of AtticFoil.com, I sell radiant barrier foil.

I'm not really here to try to knock the radiant barrier paint, I just want to give you facts

and information so that you can make a good decision on what product is right for your

home. I used to be an installing contractor, I've personally sprayed hundreds of homes,

and so I am qualified to explain the differences. First, let me talk about radiant barrier foil.

Radiant barrier foil is made by taking PURE aluminum and rolling it out into a very thin

sheet. By doing this it has the ability to reflect 97% of the radiant heat (just like

a mirror) or, to only convert, about 3% of the stored energy to radiant heat. This is

kinda like wrapping a potato with foil. Obviously a potato with foil will stay hot longer than

a potato that's not wrapped in foil. This is called the EMISSIVITY quality. Now, this

is a KNOWN property. You may have heard that NASA developed radiant barrier, or radiant

barriers, and yes, NASA did develop radiant barrier technology, this is true. But the

product, or radiant barrier, has been changed and evolved into many, many products. You

see it in fire suits, you see it in fire tents, you even see it inside of potato chip bags.

It's an undisputed art that pure aluminum reflects 97% of radiant heat. Okay, so let's

talk about radiant barrier paint. First of all, how is the paint made? All products are

a little bit different, but basically what they do is they take pure aluminum and grind

it into a very fine powder. This powder is usually added to a water-based paint, and

the paint is sprayed up into the attic. After the paint dries, you are left with a layer

of aluminum pieces. So, essentially what the paint is trying to do is re-create a layer

of foil. In theory, if it worked that simple, the paint would be a great product. The one

big advantage paint has over foil is that it can be installed very quickly. Here are

some differences between radiant barrier paint and radiant barrier foil: first of all, radiant

barrier paint technically is not even a radiant barrier. Radiant barrier, by definition, is

a product that either reflects over 90% or has an emissivity quality of less than 10%

(meaning it emits less than 10% of the heat). Radiant barrier paints are technically called

"Interior Radiation Control Coatings," or IRCCs for short, since they do not achieve

the 10% standard to be called a radiant barrier. In fact, if you look at the testing, done

by REMA Intl., only 4 out of the 18 products even meet the definition of an IRCC, which

is less than 25% emittance. In fact, some companies will take these products and rebrand

them with their own labels, and this makes it extra difficult to find any technical information

on them. You may hear that some radiant barrier paints advertise that they reflect 75% of

the radiant heat. Now understand: this is if they paint the complete roof deck AND the

complete rafters. Most spray jobs only cover the bottom of the deck and they "flash" the

rafters. Which means they only paint down about an inch or two. This allows what is

called Thermal Bypass. Basically this is the heat from the roof, conducted through the

rafters, and then it's re-radiated into the attic, essentially bypassing the paint. In

comparison, the foil is either stapled to the bottom of the rafters or its laid out

over the attic insulation. This eliminates all the thermal bypass through the rafters.

The next big variable is the installation itself. Is the paint being put on too thin?

Or too thick? From experience I know that some guys will run it out too thin. This paint

is NOT cheap and some guys will actually double the recommended coverage. It's really hard

to tell just by looking. Finally, have you ever tried to actually paint RAW wood? This

is the bottom of your roof deck - it's not smooth. In fact, the wood is really porous

and it'll just suck up the paint. The test values you see are conducted on a smooth surface,

which is not your roof deck. In order to create that smooth surface, you would need to pre-paint,

or prime, the wood. So in summary, to get a true comparison between the paint and the

foil, you've got to do all of the following. First, you've got to use one of the only 4

products that meets the requirements to be an IRCC. Second, you've gotta pay extra to

have the complete rafters painted. Then you have the have the paint applied in the correct

thickness, and coverage AND you probably have to pay extra to have the wood primed to create

a smooth surface to ensure minimum emissivity. So if ALL these variables are met, the absolute

best case is STILL about 75% reflectivity, or 25% emittance. FOIL gives you 97% reflectivity,

or 3% emittance, EVERY TIME. With all these variables, the TRUE reflectivity of radiant

barrier paint is probably in the 20-40% for most jobs. It's not even close to the 75%

advertised. Finally, I hate to bring it up, but I want you to be fully informed. Some

contractors cheat with paint. As I mentioned, the paint is really expensive and some guys

will either add water or mix in some cheap paint to make it go further. I know there

are many honest contractors out there, but it's just one more potential variable that

can effect paint. I hope this video provided you some good information comparing radiant

barrier paint to radiant barrier foil. For more information on do-it-yourself radiant

barrier foil, visit AtticFoil.com for complete information on installation, pictures, tips,

tricks, or to order online. }

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