Sorry to post a somewhat similar thread related to home cooling, but I didn’t think this would be seen in my HVAC thread.

So we need more insulation in our attic, that’s a given and going to be addressed ASAP. My question is if these radiant barrier foils are BS or not. My google searches seem to say the paint style is worthless. I’m in North Texas and it’s obviously a hot climate. If it is worth doing I’d just have it done while insulation is being put in.

Thanks again folks

A couple of my coworkers (engineers) retrofitted their houses with radiant barriers. They actually took before and after temperature measurements and were quite impressed. They talked about it for weeks as several people did it after hearing about others results.

Their retrofit was to the bottom side of the top chord of the truss so there was an air gap between the radiant barrier and the decking.

My 2016 constructed home has it. My house is 960 sq feet larger than my previous home (built in '05) in Houston and it's part of the reason my utility bills are 1/2.

Thanks for that! I’m on the fence without hearing personal experience, there’s lots of mixed info on the web. That helps a lot.

Our new place has it, it’s the type that’s built into the roof sheeting, the back side of the plywood has the foam/foil layer attached. So far pretty impressed with how much cooler it keeps the attic and rest of the house compared to our last place without.

^^. Good deal. Sounds like a good test would be putting a remote thermometer in my attic.

Just remember, it’s a no go with spray foam. Doesn’t jive too well with it.

quote:

Originally posted by smithnsig:
Just remember, it’s a no go with spray foam. Doesn’t jive too well with it.

Gotcha

I purchased rolls of it and installed in my attic myself one winter and it works. It’s easy to install and living in south Texas where it’s above 90 nine months out of the year it pays off. I even installed it in my shed. I believe this is where I got it: https://atticfoil.com

When we built our second house, we used it. The plywood that was used as the roof decking has the foil like material glued to the bottom side of each plyweed sheet. I believe it was called CoolPly. 2nd house was twice as big as first house and elect bill was a little less than the smaller house. Attic was noticably cooler.

Suggest you use along with ridge vents.

quote:

Originally posted by maxdog:
When we built our second house, we used it. The plywood that was used as the roof decking has the foil like material glued to the bottom side of each plyweed sheet. I believe it was called CoolPly. 2nd house was twice as big as first house and elect bill was a little less than the smaller house. Attic was noticably cooler.

Suggest you use along with ridge vents.

Thanks, got that covered. We had Ridge vents put in with a new roof 2 or 3 years ago.

I installed a radiant barrier on my home. I couldn't go into my attic space after 10 am in the summer. I finished the install in the summer in the afternoon. Yes it is still hot in my attic but not as hot as it was.

I installed Attic Foil during a very cool and wet May in 2016.

I live in Lewisville so you and I experience the same summers and metro heat.

My summer electric bills were (May-Sept)
2013: $125, $171, $273, $263, $301
2014: $153, $203, $266, $240, $276
2015: $140, $195, $282, $295, $295
after install-
2016: $134, $147, $217, $218, $198
2017: $125, $145, $200, $242, $200

My central AC unit is in the attic and it was working hard until I installed the Attic Foil.
Before on a 100 degree day it would cycle on for 15 minutes minimum. Now its like 5-7 minutes. And the air temp measured at the vent is a cold 55 degrees. You will want to blow in additional insulation after the install because
your current insulation will get packed somewhat from crawling around the attic. I haven't done that yet and I've already recouped my cost. Not to mention comfort level has vastly improved. I'm a big fan of Attic Foil. They are a local company. I've got some left over, email me if you would like to a sample or ask questions.

-TVz

I had my new shop wrapped in foil insulation. "Insulation" is kind of a misnomer as it's only about an R4, but it does have the foil. They did the walls and the roof. It doesn't do crap for keeping the heat in, but it does very well with keeping the heat out.

With metal siding and roofing, it was 88F here today and I was working out there all afternoon and it stayed nice and cool inside. I've been in metal buildings without it in those temps and was sweating like a whore in church, so my vote is that it works. It was a little spendy, but I'm glad I did it.

Well one of the better endorsed insulation outfits came out today. It’s over 140 degrees in our attic here in Dallas / Fort Worth. They suggested a three pronged approach. 1. Install a solar powered attic fan-approximately $1000 (definitely sounds high). 2. More insulation to get to R38- approximately $1300. 3. Radiant barrier foil approximately $3500. They were not pushy at all and admitted they were not the cheapest, but said they’d do the “best” job. BTW, our house is right at 1900sq ft.

Thoughts?

quote:

Originally posted by dry-fly:
Well one of the better endorsed insulation outfits came out today. It’s over 140 degrees in our attic here in Dallas / Fort Worth. They suggested a three pronged approach. 1. Install a solar powered attic fan-approximately $1000 (definitely sounds high). 2. More insulation to get to R38- approximately $1300. 3. Radiant barrier foil approximately $3500. They were not pushy at all and admitted they were not the cheapest, but said they’d do the “best” job. BTW, our house is right at 1900sq ft.

Thoughts?

NO to attic fan > total waste > RIDGE VENTS and Eve venting is a natural and accepted method that is VERY effective.

R35 is the standard for attic insulation

Radiant barrier is a definite > YES > spray or foil is TBD on your circumstances.


DO NOT waste money on a fan > RIDGE Vents WORK!

I already have a ridge vented roof, they claim I need more air flow. Soffit vents are blocked by insulation, which they will remedy if more insulation is put in.

You've got a ridge vent, you just need unobstructed soffit vents, with adequate insulation on the ceiling plane. As in, clear rafter bays, and use Raft-R-Mate or other product to make sure the air channel is clear.

Roof venting is about making sure there is no condensation inside the attic due to the exterior and interior being different temperatures, it's not really about keeping the roof or attic cool.

Passive air circulation is enough, and as long as you insulate the ceiling plane between the attic and your living space well, it's not a big deal if it's really hot in the attic.

Insulating the roof plane itself is worth it, if you have HVAC equipment in the attic space.

If I read correctly, the total cost of the job is $5800?

I would get a company in there to get a price on spraying open or closed cell foam in the roof rafters. Enough R value needs to be there to create a thermal break between interior temp and exterior temp.

Very good Arc, I do have two more companies coming for their take on things. $5800 would be on the high side quoted, supposedly. Of course there’s a package deal

quote:

Originally posted by smithnsig:
Just remember, it’s a no go with spray foam. Doesn’t jive too well with it.

Curious why is that?

quote:

Originally posted by ridewv:

quote:

Originally posted by smithnsig:
Just remember, it’s a no go with spray foam. Doesn’t jive too well with it.

Curious why is that?

Foam in Texas is not a good idea.
You are dealing with heat which is a much different approach than the cold parts of the country.
Radiant barriers with adequate insulation and good air flow is the correct answer.
Most new homes today use TechShield for the wood underlayment or if not a foil or sprayed on radiant barrier > not foam (foam while insulates does not reflect the heat properly).