Radiant Barriers in the Attic?

disneyjoe7

As anyone done this? If so did it help in cooling attic? Did this in the end help with power bill?


Foil or E-Barrier paint

unc2701

Don't have an apples- to- apples comparison, but my old house didn't have it and my new one does. They're both pretty unbearable in the summer, but the new one does feel a little bit cooler.

Do you have an attic fan? That made a huge difference in my first house (Talking about the kind that pushes hot air out the top and pulls it in from the eaves). I would start there if you don't have one, then make sure your blow-in is up to spec (relatively cheap), then go for the radiant barrier.

disneyjoe7

Yes I have an Attic fan, and think that works great. My blow-in is I think anyway R-19, I could go there.... But I think an E-barrier coat or foil would be better.

My Attic is pretty high and I have a RF therm sensor up there about eye level it records the high therm. My attic high was 128.5f last Saturday.

mufsoman

disneyjoe7 - i'm not an expert, however, from a logical standpoint, i don't think a foil E barrier or paint in the attic will do anything. The heat is already in the attic, e barrier won't stop that. To unc2701's point, make sure there's proper air movement in the attic. Even if you have an attic fan, if you don't have the right amount of soffit vents, you may not be getting the appropriate air movement/replacement in the attic. Make sure your soffit vents are not covered with insulation or clogged with dust/dirt. You can also check out website that help you to calculate if you have the proper amount of vents.

From a personal experience standpoint, I just had another layer of cellulose insulation blown into our attic and it has made a HUGE difference. I also crawled aound the attic (before the blown insulation) and caulked every opening I could find that was in the ceiling; such as crack around ceiling electrical boxes, bathroom fans, piping, vents, etc. It's really made a difference. I had approx. R25 insulation factor before. Now I have 50 - 60R, which is within spec for Chicago. In Florida, the spec is R30-R60. If you only have R19, your really under spec. Get some more insulation blown in there!!!

disneyjoe7

I know R-19 isn't current spec for attic insulation as of today, but think it had to be for the year it was built 1996. Spec's changed to R-30+ in 2006.


Steve

gdb

If.....you'd like to test a foil barrier cheaply, I suggest going to Costco, etc. and buying a BIG roll of aluminum foil in the food service supplies area. (or a couple) 18" X 1000' covers A LOT of attic space for basically,chump change.

disneyjoe7

Funny you state that I considered just that, but think it's a complete PITA with roof trusses. Also attic height to peak is an issue being so high, it's not safe up there as there's no place to stand. So liked the paint idea, even if not as effective overall.

potee

Go online and look at attic solar fans. My friend has one and I think I'll get one.

disneyjoe7

The problem IMHO is that solar fans are under-powered not moving enough air. But on that subject I use a large powered fan.

bmbguy

disneyjoe7 wrote: »

As anyone done this? If so did it help in cooling attic? Did this in the end help with power bill?
Foil or E-Barrier paint

We stapled foil up on the roof joists in much of our attic a few years ago (didn't have quite enough foil to do every spot). One area we noticed a huge difference in was the garage, the roof of which was covered completely with the barrier (because it was easy to get to!), and which has no insulation above its ceiling (6-8 feet between garage ceiling and roof). We also put the foil barrier on the inside of the sections of the garage door (which is in full sun in the afternoons). The garage, while still hot (hey, it's Texas in the summer...), is noticeably cooler than before the foil application.

Just my experience with the foil.

disneyjoe7

I could see a lower attic temp, I would think that could be little lower electric for AC system. Have you seen a difference of that?

dorokusai

We installed a fan for cross ventilation in our attic and it was a dramatic change in cooling and ambient temperature in the attic itself. It also created a vacuum so the also newly installed attic stairs needed to be sealed properly. We have an older home so until the roof is redone, no roof/ridge vent exists. It was a modest $250 install and has helped a lot with the air flow and migration around our bedroom area(The fan is in the hallway, at the end, near our Master). The next step for us is to vac all the old insulation out and get some higher R blown insulation distributed above. That combined with our upgrade in siding and sheathing SHOULD be quite noticeable in the end and lower our costs quite a bit.

bmbguy

disneyjoe7 wrote: »

I could see a lower attic temp, I would think that could be little lower electric for AC system. Have you seen a difference of that?

Since we've also made many other changes -- added insulation in the attic, used/not used just a window A/C unit at night, added acrylic sheets to inside of windows -- we didn't get a good apples-to-apples comparison of just the foil's effect. But the difference in the garage was one we noticed right away.

Everything helps though. Problem is that you have to actually check KWH used, as power prices go up all the time. And last year in TX, with 80-or-so days of 100+ temps, nothing helped!

disneyjoe7

Well I use an online payment of my electric bill and I can see 24 months ago to see what the other year bill was is.


My current bill Kw per day.

DAILY AVG. USE - 56 KWH/DAY
USE ONE YEAR AGO - 62 KWH/DAY
DAILY AVG. ELECTRIC COST - $7.00


My house is all electric, and I have a refrig in the garage, a pool, and run house / pool lights every night. My pool lights are LED and the house lights are CFL.

A savings but also looking to reduce my electric bill.

B Run

I do home inspections so I spend a lot of time in attics, and I think radiant barriers do help to an extent. Honestly I think the best two things you can have to keep your attic cool is proper ventilation (ridge vents are bullet proof) and at least 10-13 of insulation. A combination of the three can drastically reduce attic temperatures and help keep bills lower.

disneyjoe7

In this thread some good ideas have come up and I was thinking same.

A.) sealed / caulked electrical boxes, bathroom fans, piping, vents, and everything else I can find.

B.) add insulation to R-38

The question is the radiant barrier, if I was to do that I would before the R-38 insulation upgrade. I think and believe my vent for the attic is great, with the attic fan.

disneyjoe7

My roof is hip roof where the all side come up. So I have 3 vents not sure what they are called, but maybe "Static Roof Vent". They are like 4' wide and 4" high.

VR3

I installed 24"+++ of Insulation and an attic fan a little over a year ago... I actually am making money compared to my old power bill at this point...

disneyjoe7

dorokusai wrote: »

We installed a fan for cross ventilation in our attic and it was a dramatic change in cooling and ambient temperature in the attic itself. It also created a vacuum so the also newly installed attic stairs needed to be sealed properly. We have an older home so until the roof is redone, no roof/ridge vent exists. It was a modest $250 install and has helped a lot with the air flow and migration around our bedroom area(The fan is in the hallway, at the end, near our Master). The next step for us is to vac all the old insulation out and get some higher R blown insulation distributed above. That combined with our upgrade in siding and sheathing SHOULD be quite noticeable in the end and lower our costs quite a bit.

Mark, is this a whole house fan? The kind which is like 3' feet wide and in the ceiling to the attic?

dorokusai

disneyjoe7 wrote: »

Mark, is this a whole house fan? The kind which is like 3' feet wide and in the ceiling to the attic?

No, just an attic fan.

Don't forget to seal your dryer vent. I could feel cold air out of mine until I had my siding and attention changed.

disneyjoe7

Thanks Mark, I would have missed that, since the dryer vent is on a wall to outside.

disneyjoe7

Thinking to go with this product.

http://hytechsales.com/prod85.html


Then see this page.

http://hytechsales.com/testimonials.html

rpf65

I do this kind of work for a living, in central Texas. The place that had close to 100 days of 100+ degree temps last year. I've been in may really hot attics. The best value will be adding insulation, this keeps the heat load away from the cieling, which helps keep the coolon the house.

I didn't believe radiant barriers worked either, until you actually experience it. The best on the market currently in heatbloc-ultra(www.heatbloc.net). This stuff really works. As far as solar fans, there are some very good ones, we deal with a manufaturer that garuntees within 15 degrees of ambiant, if you have enough supply ventilation. Pricey at over $1,000 each, but agin they work and are guaranteed for life.

goofyGAguy

^^^^^^^^^^^ :rolleyes:

pitdogg2

gdb wrote: »

If.....you'd like to test a foil barrier cheaply, I suggest going to Costco, etc. and buying a BIG roll of aluminum foil in the food service supplies area. (or a couple) 18" X 1000' covers A LOT of attic space for basically,chump change.

yea that won't work you need a thermal break.
one word
Reflectix here's a link it works. I line my windows in the winter really knocked down my heat bill(single pane windows)

http://www.energyefficientsolutions.com/radiantbarrier.asp?gclid=COP-2Z2RybECFc_IKgoddkUAqQ
you must use the metal tape or you're just wasting time and money

gdb

Yeah, you're wrong. A foil film is a reflective surface, and thus performs as a thermal barrier when used in conjuction with existing insulation materials or without them. If you choose to swallow one manufacturer's propaganda and view it as "gospel".....

disneyjoe7

Back on foil paint / coatings....


Foil based only or....

Foil / Ceramic coating any merit?

samfraser

Aluminum foil can be used as a thermal break, as it has a low emissivity value, meaning it reflects a higher amount of radiant energy than it emits, however, aluminum is a very good conductor.

dkg999

You need to watch the heat reflectivity of whatever radiant barrier you install. There was an article in one of my remodeling trade journals not too long ago about shingle and roofing failure due to excessive heating of the roof deck due to either the heat reflectivity or installation of the radiant barrier. As has been noted, proper air-sealing of all ceiling air leakage and the right amount of ceiling insulation combined with adequate venting is the first step(s).

tonyb

Man Steve, you and that attic have a rocky relationship. Rodents....now heat....before long a Python will take kindly to your attic. Good luck on the foil or whatever you use.

disneyjoe7

Plan to seal up any and all holes in walls to bring down some wiring. Also many ceiling light cans which I sure could use some help, they are all IC type. I'm not sure what to do with the Radiant barrier idea, I like the foil or foil type boards but with trusses and attic height its a no go. I have talked with several people I know whom have or had a Radiant barrier foil type and they find value in it as they feel or know for a fact it helps. But all people I talked to need to redo / replace or rethink foil thing since it has been destroyed by the hurricanes several years ago. So I still like the Radiant paint / coating idea, knowing it maybe not 100% of foil but something is better then nothing in my book. Also like do to fact it can't be damaged so easy in a storm, which I can get a crazy storms everyday here.