Radient Barrier - does it work (Howe: apartment complex, home, neighborhoods)

[City Love]

Originally Posted by mtgmike

Virtually nothing. OSB with the radiant barrier on it is almost the exact same price as OSB. MAYBE a buck a sheet???


Edit*** Homedepot.com std osb $6.97 radiant barrier osb $8.97. That is for a 4 ft x 8 ft sheet.

Definitely worth it for an older home getting a new roof done. It's quite common to have to redeck some of the roof, might as well do it.

[texsn95]

AtticFoil® Do-It-Yourself Radiant Barrier Foil Insulation is where I got mine, next day shipping and works great.

[tstone]

Hate to go against the grain here, but I know someone who got one and says it was a complete waste of money.

I know they work in new builds where the barrier is engineered into the overall design of the home. But I've heard mixed results on those who retrofit older homes with one. I think it depends on how well-insulated and well-built the house is to begin with.

I'm suspicious of those "deals" where you get 'free' insulation with a radiant barrier.

I've also been told to avoid if you heard about it on 740AM.

[mtgmike]

Well, the barriers installed afterwards are harder to install properly, and have more problems than new decking with the barrier. A house with fresh barrier decking will be fine unless it has serious issues otherwise. My house is ten years old, and the before and after "sweat factor" in the attic was tremedous. Im waiting a full year of "after" bills to do the math on it.

My father went with the spray on version that I strongly advised against. Too many variables, but he already had a nice plywood decking, and his roof was fine. He claims the sweat factor was better in the attic. I got up there once, and it wasnt too bad, but he wont take the time to compare bills. You also need unusually easy access to the entire roof to make this a decent option.

[behtypa]

Originally Posted by texsn95

AtticFoil® Do-It-Yourself Radiant Barrier Foil Insulation is where I got mine, next day shipping and works great.

Ditto.
I checked AtticFoil price against Home Depot and Lowes and it was a little cheaper. I don't know about this season.

[behtypa]

Here is a few links to related articles here:

//www.city-data.com/forum/houst...-personal.html
//www.city-data.com/forum/houst...rth-money.html
//www.city-data.com/forum/houst...n-service.html
//www.city-data.com/forum/houst...fficiency.html
//www.city-data.com/forum/houst...t-another.html
//www.city-data.com/forum/houst...-possible.html
//www.city-data.com/forum/houst...th-answer.html

[behtypa]

Originally Posted by texas7

Looking at a nice older home (about 24 yrs old) and it has solar screens and a radiant barrier. As they have added both - am guessing they are trying to cut electric bills but wondering from anyone who has added the radiant barrier - does it really help significantly?

I have spent a lot of time researching this field. Short answer: It does help a bit.
- To give you an idea, the radiant barrier would cut the bill maybe 5%.
- Solar screens would cut more if windows are facing South. Say, 10%.
- Loose fill or bat insulation in the attic would add more - about 30%. Sealing all crevices (outlets, cracks in vents, door/window crevices) will add another 5-10%.

If that house solar screened windows face North, they are not as effective as for the Southern exposure.

Radiant barrier bounce back only some heat waves. It heats itself, so some air space is required between the foil and the roof decking + foil perforation preferably.

[behtypa]

Originally Posted by texas7

Looking at a nice older home (about 24 yrs old) and it has solar screens and a radiant barrier. As they have added both - am guessing they are trying to cut electric bills but wondering from anyone who has added the radiant barrier - does it really help significantly?

If the house is 24 yrs old it most likely means that:
- walls are R9 at best, which is not much. But most houses are like that.
- attic blown insulation is R30 at best, minus 30% for settling down over time = actual R20.
- etc.

If the price is right you can do the energy audit later:

- Infrared camera audit
Thermographic camera - Wikipedia, the free encyclopedia

- Blow door test
Blower door - Wikipedia, the free encyclopedia

[geraldreece]

Radiant barriers actually keep the attic from being so HOT! Having an oven above your home will cause your HVAC system to work harder...any reduction in the use of the HVAC is a energy cost saver as it represents about 50% of energy costs here in Houston.

[crone]

When we put a new roof on to replace the existing, worn out wooden shingle roof many of my neighbors were putting the roof decking with the foil on the attic side. I requested the same from our roofer. He said it would not do what I expected. I inquired why, what about all of this radiant barrier going in all over the neighborhood. He brought the manufacturer specifications that indicated that it does not work when replacing wood shingles due to the 1x3 boards the shingles were nailed to. 1/2 of the foil is covered. New construction, fine. Replace old decking on an ordinary asphalt roof, fine. Wood shingles, no. Everyone I have talked to also says when it gets dusty, it loses it's effectiveness. Folks in the business tell me to put in more insulation, rather than radiant barrier. And good attic ventilation.