muckyp
Member
Does anyone have any experience with the spray on radiant barriers I keep hearing about? From what I have seen, it looks like silver paint applied to the roof decking from inside the attic. Does it do all they say it will do?
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Spray on attic Radiant barrier
- Thread starter muckyp
- Start date
bigdav160
Well-known member
Radiant Barriers work!
Beware that most paints are not "radiant barriers" because they do not reflect enough.
True radiant barriers need to be 90% before they can be claim the name. The best paints are 75% some are 0%
Somewhere on the web are independent test results from the various paints.
Beware that most paints are not "radiant barriers" because they do not reflect enough.
True radiant barriers need to be 90% before they can be claim the name. The best paints are 75% some are 0%
Somewhere on the web are independent test results from the various paints.
Here is some good info comparing radiant barrier spray to radiant barrier foil. I installed the foil and it made a big difference.
http://atticfoil.com/radiant-barrier-spray.htm
http://atticfoil.com/radiant-barrier-spray.htm
Frank
Well-known member
Does anyone have any experience with the spray on radiant barriers I keep hearing about? From what I have seen, it looks like silver paint applied to the roof decking from inside the attic. Does it do all they say it will do?
Small world. I'm in Mesquite too.
I have been seeing the commercials and wondering about them too. Seems more effective than just attic vents/fans alone
dodgepolara500
Well-known member
when i added onto my home, i did not know that you could buy plywood with the foil backing attached. My house in San Jose, CA gets very warm in the summer due to my black asphalt shingles. I have two electric fans in the attic and it still gets over 80+ in the house on some days. I was thinking of adding the foil to my attic but did not want to do so unless I was sure it was going to work.
Anyone try this yet?
Thanks
John
Anyone try this yet?
Thanks
John
dodgepolara500
Well-known member
I sent my post without catching your respone SpuMaker. How much cooler did it make the inside of your home?Here is some good info comparing radiant barrier spray to radiant barrier foil. I installed the foil and it made a big difference.
http://atticfoil.com/radiant-barrier-spray.htm
thanks
John
It's hard to say exactly. The attic is a lot cooler. The main thing we had to do was Raise our thermostat 3º from 75º to 78º. It actually got too cold keeping it where we used to. So, I know that this alone is saving me money and the house is more comfortable.
I too am a firm believer in the radiant barrier.
We just finished building our new house several months ago and I spec'd the roof sheathing to be the foil backed variety. Using that coupled with ridge vents and the continous soffit vent hardi-board has made a huge difference.
Since it is new construction, I really don't have any prior energy usage to compare it to, but I had to go into the attic in the middle of the day last week when it was 102* outside. When I climbed up there it was basically the equivalent of being in the shade outside. I didn't even break a sweat, and I was having to climb around getting the serial numbers off of the air handlers.
In our last house that didn't have the barrier, used turtle-backs instead of the ridge vent, and had a limited number of soffit vents; it would have been at least 130*-140* on a day like that in the attic.
Now I didn't pay a lot of attention in thermodynamics class, but do remember a little bit about heat transfer phenomenon; hence, having your attic about 30*-40* cooler has to decrease the load on your HVAC units. If you can't reduce the heat in the attic, you can achieve the same heat transfer rate by increasing the resistance between the attic and the living space by adding extra insulation.
The barrier cost a little bit more than the standard sheathing, but in the overall scheme of the house, the added expense was not an issue. Especially since it will keep paying for itself as energy cost continue to rise.
Now after typing all of that I realize that the OP was asking about the spray on variety. When researching radiant barriers in the planning stages of our house, I recall that the spray on worked, not as good as the foil barrier, but it did block some/most of the heat and if that is your only option, I would still go with it. Especially if you couple it with added insulation. I don't see the cost of energy going down anytime soon, so anything extra that you do now will continue to pay for itself.
Sherwin Williams sells the paint if you want to DIY, but IIRC you have to have a special sprayer to spray the paint since it has metal particles suspended in it.
We just finished building our new house several months ago and I spec'd the roof sheathing to be the foil backed variety. Using that coupled with ridge vents and the continous soffit vent hardi-board has made a huge difference.
Since it is new construction, I really don't have any prior energy usage to compare it to, but I had to go into the attic in the middle of the day last week when it was 102* outside. When I climbed up there it was basically the equivalent of being in the shade outside. I didn't even break a sweat, and I was having to climb around getting the serial numbers off of the air handlers.
In our last house that didn't have the barrier, used turtle-backs instead of the ridge vent, and had a limited number of soffit vents; it would have been at least 130*-140* on a day like that in the attic.
Now I didn't pay a lot of attention in thermodynamics class, but do remember a little bit about heat transfer phenomenon; hence, having your attic about 30*-40* cooler has to decrease the load on your HVAC units. If you can't reduce the heat in the attic, you can achieve the same heat transfer rate by increasing the resistance between the attic and the living space by adding extra insulation.
The barrier cost a little bit more than the standard sheathing, but in the overall scheme of the house, the added expense was not an issue. Especially since it will keep paying for itself as energy cost continue to rise.
Now after typing all of that I realize that the OP was asking about the spray on variety. When researching radiant barriers in the planning stages of our house, I recall that the spray on worked, not as good as the foil barrier, but it did block some/most of the heat and if that is your only option, I would still go with it. Especially if you couple it with added insulation. I don't see the cost of energy going down anytime soon, so anything extra that you do now will continue to pay for itself.
Sherwin Williams sells the paint if you want to DIY, but IIRC you have to have a special sprayer to spray the paint since it has metal particles suspended in it.
dodgepolara500
Well-known member
This makes me even more bent that my contractor did not add the ridge vents or radiant foil plywood to my home. I have powered mushroom fans and eyebrow vents and they dont seem to help worth a damn. I would have gladly paid the difference at the time, but did not know about it. I may add radiant foil to the attic studs now, but what a pain.
I have been in Texas (Plano) for almost two years, and have been prepping for summer and the pending high electricity bills.
From my research, the biggest "bang for the buck" comes from weatherization. I have added an attic tent, fireplace plug (or balloon), gasketed all of my outlet plates (especially those on exterior walls), caulked my windows, sealed my ac intakes inside the house, added door sweeps and weatherstripping where needed and used "Great Stuff" to seal plumbing around the house.
I just had a blower door test performed to see where I was and if I had missed anything. BTW, this test is pretty cool, and does a great job pinpointing air leaks. Well worth the $120.
I spent a while talking to the tech that performed the test. He said the order of importance was insulation, ventilation, radiant. The radiant barrier, paint or film, needs to be able to evacuate the heat. He said that if you have ventilation and your attic gets to 140 degrees, add radiant, it will save you money, in time. If less than 140 degrees in the attic, radiant barrier is a house comfort item, but has a 5 year + payback.
His company sold the paint system, and its cheaper than the foil. he said the foil works better, but by a small percentage. Dust on the foil negates this difference pretty quickly he said. His perspective was that the paint was quicker (and therefore cheaper) to apply, which gets you positive savings faster. This reduced offset cost overcame the small difference in efficiency between the paint and the film.
This is his opinion, and not necessarily mine.
From my research, the biggest "bang for the buck" comes from weatherization. I have added an attic tent, fireplace plug (or balloon), gasketed all of my outlet plates (especially those on exterior walls), caulked my windows, sealed my ac intakes inside the house, added door sweeps and weatherstripping where needed and used "Great Stuff" to seal plumbing around the house.
I just had a blower door test performed to see where I was and if I had missed anything. BTW, this test is pretty cool, and does a great job pinpointing air leaks. Well worth the $120.
I spent a while talking to the tech that performed the test. He said the order of importance was insulation, ventilation, radiant. The radiant barrier, paint or film, needs to be able to evacuate the heat. He said that if you have ventilation and your attic gets to 140 degrees, add radiant, it will save you money, in time. If less than 140 degrees in the attic, radiant barrier is a house comfort item, but has a 5 year + payback.
His company sold the paint system, and its cheaper than the foil. he said the foil works better, but by a small percentage. Dust on the foil negates this difference pretty quickly he said. His perspective was that the paint was quicker (and therefore cheaper) to apply, which gets you positive savings faster. This reduced offset cost overcame the small difference in efficiency between the paint and the film.
This is his opinion, and not necessarily mine.