Radiant Barrier Paint vs. Foil - What's The Difference?

[boogerchamp]

What if you used both foil and paint?

[AtticFoil]

@boogerchamp Why? Foil will reflect 97%. If you use both, assuming the paint stopped 60%, then the foil would reflect 97% of the 40% that got through. - Still about 97%. It's like wearing having two umbrellas - if the first one works, you don't need a 2nd one.

[dogfan4lyfe]

I am looking to put some radiant barrier foil in both my garage and in my attic. My garage doesn't have any insulation or ventilation whatsoever. Would it be a good idear to install a ridge vent with some soffit vents first?

[AtticFoil]

@dogfan4lyfe Yes, any "hole" in the top will work. I'd go with a simple wind turbine. Then add some soffit vents. If you have a pull down staircase or a scuddle hole, leave/prop it open and then adjust the sensor on the garage door opener to stop about an inch before the concrete. This will allow air to come into and out of the actual garage. Combined with radiant barrier the garage will be significantly cooler.

[dogfan4lyfe]

@AtticFoil You think a wind turbine would be better than a ridge vent? I live in the midwest with both hot and cold. Is it going to make my garage freezing cold in the winter? Thanks for your videos and reply.

[AtticFoil]

@dogfan4lyfe It depends. You basically need a "hole". One wind turbine equals about 5-15 of ridge vent depending on the type. I like ridge vent for low-pitched roofs with lots of ridge. For higher pitched roofs or hip style roofs wind turbines work great and are cheap and easy to install.

Cold garage? The roof is supposed to be cold to prevent ice dams. Yes, an unheated, uninsulated garage will be cold in the winter. If you want to keep it warmer, add insulation and/or a heat source.

[jeevespreston]

I am sold on the concept of attic foil. If I am re-siding my house, can I use this as a barrier underneath the new siding? Would it be effective, any downsides? If I am having my roof re-done, can I have the roofers place this on top of the sheathing and underneath the shingles rather than crawling into the attic to mount it?

Thanks,

Gary

[AtticFoil]

Gary, you cannot put foil directly between shingles and the sheathing.

Go to my YouTube channel and look for the video "Radiant Barrier Under Shingles Won't Work Without An Air Space" Or here: atticfoil(dot)com/radiant-barr­ier-shingles.htm

It will work under/behind siding IF there is an air space. This can be done with furring strips. If the siding overlaps and has gaps behind, it will still work but will loose some if it's effectiveness where there is no space.

[2wheaties4me]

We just had it installed in my home. They rolled it on the floor of the attic over the master bedroom & the attic of the other bedrooms on the 2nd floor. I didnt like the way it looked, but I learned alot from your videos on the importance of the air gap needed. Its been 1 1/2 months since the install & cooling bills are still the same. This home is brand new construction in '08, & cant figure out where we went wrong? Attic air ishot, but under barrier on floor its cooler..its working i guess..?

[AtticFoil]

My guess is lack of attic ventilation. You say the attic is hot? Radiant barrier is really about reducing the top surface temp of the insulation. IF you have bad ventilation the AIR can STILL be 130º or more. So, your top surface temp will be 130º If you can get air temp down (more holes in your attic) you should see a difference. Same thing happens with ducts in poorly vented attic. Can't stay cool. Call me if you want some more tips. Ed

[MrGreenvision]

If the Radiant Foil was only installed on top of the bedrooms and not over the hallways, bathroom, kitchen, dining room, closets etc, then that a problem cause the hot air is still coming through "Conduction Heat" in those places. Insulation should be place all over the attic to have a greater effect. Also, like Mr. AtticFoil said, Poor Attic Ventilation can be another problem. Adding "Baffles at the eves, more fans, and more vents can help with this problem. Hope this help. Foil Rules!

[d1incharge]

As long as it is well vented I understand, but paint is not trying to be foil. There are many attics I have seen that would be a 3 hour spray job vs. 20+ hours for foil. How do you enjoy your time in Texas attics during a heat wave??My opinion: just start selling paints too, they are getting better. Ever installed roof sheathing upside down and tried walking on it, its pretty dang smooth. I dont think your real world numbers for paint effectiveness are realistic, your foil isnt perfectly smooth.

[AtticFoil]

I agree that the foil can and often does take longer to install. The video is about the differences between foil and spray and all the variables that can effect the performance of the spray. Whereas the foil always reflects 97% of radiant heat. The challenge with paint is you can't be certain if you are getting a 75% reflectivity install job or a 20% job. I've personally sprayed hundreds of homes and yes it can be a good product IF it is installed correctly and honestly.

[d1incharge]

can and often does??? are you trying to sell it as if it is not more labor to install foil 100% of the time????Not just way more labor,but laying on your back in rat turd infested 80 year old insulation in a 140* attic for AT LEAST twice the amount of time as spray.(which rarely involves being on your back) Another advantage to spray is 10-20% better coverage than foil. I can spray two feet past where you can foil, all of the way around the house.

[AtticFoil]

I think you may be lost. This video is not about ROI or ease of install. It's about the difference between foil and paint. I'm never going to dispute painting is faster. As far as coverage. It is all about btu heat flow. If you cover 50% with foil and block 90 +% of radiant heat, you will reduce more heat flow than full coverage with spray blocking about 50% of radiant heat. You are welcome to your own opinions, but not your own facts.

[d1incharge]

I understand your points, but most old homes and a lot of new have such tight or chopped up attics that it would be triple or quadruple labor and double or more the overall cost. If the goal is ROI, and the spray is only 15-20% less effective, but 1/3 the cost???? The feds rebate for spray, our local electric compay rebates and recommends spray or foil. You have to admit the foil gets hot, it doesn't reflect 97%, it just does not re-emit more than 3%.My point=4000sqft of foil x 2 heating air.

[AtticFoil]

Thanks for the comments. Because of it's emissivity foil does not get hot in the sense it does not "hold heat". This is why you can reach into a hot oven and pull out the foil off a turkey. As far as the feds rebate for spray. You are mistaken. Please cite an official source.

[RicardoSabong]

for a climate like Houston , where do you recommend i place the attic foil, should i place it on the floor or on the rafters? I am seriously considering your product. I will get some one to help me and still it will be cheaper than having a company install it.

[AtticFoil]

If you have ducts in the attic my preferred method would be to staple it up. If no ducts, then just lay it out. If stapling is too difficult, then lay it out even with ducts in the attic. There is perfect and good. Sometimes the enemy of good IS perfect. Don't overthink it. Just get foil between the roof and the insulation and get it done. Ed.

[Connect2Homes]

Disclaimer: I do install one of the four true radiant barrier paints mentioned in the video around the Houston area. (Lo-Mit II)  My concern with foils is that if that gap between the rafters is not closed off or properly vented the shingles will have a reduced life spam. The more complicated an attic the better looking paint products are. Smoore19's points are also legitimate. Plus what does gravity do to the foil over time?

[AtticFoil]

Lo-Mit II is a good products. However, it still is not a true "Radiant Barrier" It does meet the standard to be an IRCC (Interior Radiation Control Coating). As long as you leave a space at the top and bottom of all foil you can never "trap" the air. The DOE Oak Ridge Lab did some testing and found shingle temps only increase 2º-10º over radiant barriers which is insignificant. Gravity? With a few staples it will still be there long after we are gone.

[MrGreenvision]

Thanks for the info. Very informative and will do my research. My vote has always been with foil. Harder to put on, but better product.

[AtticFoil]

Thanks for the comment. As I mention in the video, paint is basically trying to BE foil. So, why not just use foil?

[rok30]

great job