Heat moves in 3 ways.
- Convection (air-movement)
- Conduction (direct transfer through solid objects)
- Radiation (light waves move from hot objects to cold objects)
A radiant barrier simply blocks light waves and there are 3 grades to choose from:
- OPEN CELL BUBBLE WRAP
- INSULATING WRAP
Foil. As a building product doesn’t pass the field test. We have installed it, it worked okay, but it is too darn fragile, and the cost versus much better products is a joke. The stuff is perforated, so if you install it against the walls in an attic it lets unwanted convection occur.
Bubble wrap. Available in white or silver, and in 1′, 2′ & 4′ widths at Lowe’s or Home Depot. This product is great for air-sealing. All you need is a knife or scissors and a staple gun. It does reflect heat well, but the down side is that big bubbles just like the ones little kids like to pop, don’t insulate at all against conduction. In other words you miss out on some benefits when application is against wall studs.
Insulating Wrap. The best product we have found is PRODEX TOTAL RADIANT BARRIER which is durable, great to work with, and can be installed to prevent all three types of heat loss. I have seen a fiberglass filled version, but I try to stay away from fiberglass. We love PRODEX; the toughness of the product, dealing with the manufacturer, and the staple tabs. We use this product on attic ladders, water tanks, access doors, and crawlspace walls in addition to bonus rooms or other attic wall applications. It is such a great product because it is so versatile.
Be weary folks selling radiant barriers. If they propose installing the product against the roof or rafters, you might not get any noticeable results. It is more important to complete air-sealing, duct-sealing, sealed crawlspace, and duct-replacement first. Radiant Barrier isn’t all some folks say it is! In fact, it is often better to double the size of gable vents and add ridge venting than installing radiant barrier materials.
Even the plywood flooring in your attic is a radiant barrier, and at-least you can walk on it. Call for Questions. (919) 413-2326