Reflective Foil Insulation

« back to Heating, Ventilating, Air Conditioning (HVAC) & Water Conditioning forum

Topic by Arnold posted 06-06-2011 12:17 AM 5288 views 1 time favorited 8 replies Add to Favorites Watch
View Arnold's profile


10 posts in 3917 days

06-06-2011 12:17 AM

Topic tags/keywords: insulation reflective foil insulation remodel

Anyone ever use reflective foil insulation?
Any facts, opinions?

Been looking at being advertised and sold lately.

I was wondering how effective it really is. I can see that its like what you would put in your car to shield out the suns rays, but Under a roof? They say it blocks radiant heat.

I’m just kinda lost on this. To me this seems like a new product and don’t know much about it.

My 2 story home was built in 1942 and I don’t have any insulation in it. I’m exploring options to try to retrofit my home. There’s different places and ways to install it, and I’m seeing some contradiction between explanations.

I’ve heard some say that if I don’t have insulation, that I don’t need it with this product. Which would be great if it were true. Then some say I need insulation. I believe the answers I’m getting is a mixture of science, old ways, and many opinions.

I see their demos of side by side comparisons and effectiveness of their product. The put two heat lamps side by side. They shine down on some insulation and their is a temperature probe in each. One side is only that which I described and the other has a a sheet of foil insulation protecting it. The foil insulation is definitely cooler by the temperature probe. Yet, This demo of sorts is defective. I agree it would keep the heat out, but the foil is sitting on top of all of it. Yet the product ends up being installed under your roof, and not over your roof on the outside which the demo thing is doing. I understand how it keeps the heat out if the foil insulation were to be installed over your whole house. Just fail to see how it would be as effective being installed under your roof. Your shingles, and wood are still over it and still get baked with the sun and still transmits heat through the roof and thereby through the foil. Same thing as in an over. Foil DOES prevent the heat source from burning your food, but it still cooks the turkey. But… the foil is on top… and not inside your turkey… you understand what I’m trying to say?

View Grandpa's profile


139 posts in 3330 days

06-07-2011 04:55 AM

I have seen a reflective material that was stapled on the bottom side of the rafters. This is a filmy product. the magazines tell us that will reduce the temperature of the attic by 40 degrees I think is the report. My son bought a home with this stuff in the attic. He has blown fiberglass on the floor of the attic. I think this product helps but I am not sure it helps as much as reported. I think attic ventilation is the most important thing we can have. I should say that I live in a part of the country where we cool about 7 months a year. It was 101 deg here today and it is June 6. I did go into an attic today and the 100 deg temp outdoors felt good when we got out of that attic. Not the first time we have reached 100 this spring. I think the best homes here have plenty of ventilation and 16 inches of blown fiberglass. That is where my money would go. Ventilation gives you longer life on the structure and a much longer life on comp shingles. If you live up north you probably know about ventilation that those of us in SW Oklahoma. BTW I am a licensed home inspector if that helps any. I dont’ know all and don’t claim to know all but I do study and have studied these things. I read a great deal about these things and try to retain most of it. That is getting more difficult with age…LOL Use air chutes along the edges of the roof so the air can get into the attic when you put that insulation in there if you have soffit vents. My Systems & Standards book says you need a sq ft of ventilation for every 150 sq ft of attic floor space. Half of this are ahould be high in the attic (ridge vents, turbines, power vents or turtles. the other hlaf should be soffit vents or vents that are low on the roof or in the lower part of the gables. A couple of gable vents high in the gable was used in the old days but we have found that this is not adequate especially with our modern “tight” homes. Think about that fiberglass insulation instead of the foil material. Blow it in and don’t disturb it for best results. Cloth wrapped electrical wiring doesn’t like insulation. The cloth material will come off the copper wiring with insulation. I hope some of this helps.

View SteveVo's profile


5 posts in 3032 days

03-21-2012 08:24 AM

If you have a roof that is flat, you can even consider planting a garden on your roof. They provide good insulation. I do not know much about these reflective insulation, but if you are able to crank up your radiators to provide enough warmth, then probably you do not need insulation. Unless you want to save on bills.

-- Steve | http://www.radiatorshowroom.co.uk

View dbhost's profile


4 posts in 3580 days

03-23-2012 08:15 PM

I am in the process of installing “Attic Foil” which is basically an alumized mylar type sheeting that staples to the bottom side of the rafters. A colleague of mine did his roof about 2 years ago with this product, and the temp difference in his attic in the summer is every bit of 30 degrees cooler up there. Cut his electric bill by about 1/3 during the peak A/C usage here in coastal Texas…

View Grandpa's profile


139 posts in 3330 days

03-27-2012 03:41 AM

dbhost, I have read information that is consistent with what you are saying. When the temps soar like they do in my area we should be looking at his stuff. Where did you find yours?

View adah1256's profile


5 posts in 2756 days

12-22-2012 09:54 AM

This is very nice to see this nice information in this community.

-- AC Replacement Houston

View adamjohn's profile


4 posts in 2697 days

02-20-2013 07:04 AM

hopefully this clip would be help for you in rectifying your problem, in which high grade commercial aluminum foil that is used to reflect radiant heat. , http://www.youtube.com/watch?v=kabzjaKvXIc
Heating repair Arlington VA

View Skidog's profile


8 posts in 2594 days

08-23-2013 02:41 PM

I have used foiled backed plywood on a roof deck, and it actually held down the temp in the attic by about 35 degrees. I built 2 identical buildings, with the same amount of sun exposier, and the first one I used regular plywood and the 2nd one had the foil backed plywood. I took readings of both during the hottest part of the summer, and the 2nd one was 35 degrees cooler in the attic than the other one!

View Arnold's profile


10 posts in 3917 days

08-23-2013 07:47 PM

Thanks for the info, anyone else use this product.

You must be signed in to reply.

DISCLAIMER: All views and comments posted by members are not necessarily those of HomeRefurbers.com or of those working on the site.

Latest Projects | Latest Blog Entries | Latest Forum Topics

LumberJocks.com :: woodworking showcase