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Frequently Asked Questions about rFoil reflective insulation and No-Tear Radiant Barrier

If you've discovered rFoil reflective insulation for the first time, you've probably got lots of questions. So we've developed this page from the questions we've heard from our customers to help you with yours.

But if you don't find the answer to your questions here, let us know. Who knows? Maybe you'll be the latest addition to our FAQ page.

If you don't know some of the construction terms we use here, please check out our Construction Techniques and Terms page.

(Hint: you're getting awfully close to the hidden rFoil special if you do).

    Get rFoil Reflective Insulation Quote Get rFoil Reflective Insulation Literature
    FAQ about rFoil reflective insulation and No-Tear radiant barrier Get rFoil Reflective Insulation Installation Instructions

    The questions

    What are the reflective insulation products you have?

    There are several products in the rFoil line:

    • rFoil Single Bubble Foil and Double Bubble Foil
    • Concrete Barrier
    • No-Tear Radiant Barrier
    • rFoil Ruff Rap housewrap
    • rFoil Single Bubble Poly and Double Bubble Poly

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    How does reflective insulation work?

    Hopefully you've been reading about this throughout the website, but we're happy to tell you again:

    Reflective insulation and radiant barrier are designed to block RADIANT heat. Radiant heat travels through space from a warm surface to a cooler surface. It can be heat from the sun, an electric heater, or even holding your hand above a warm stovetop.

    Reflective insulation will block up to 97% of radiant heat, while regular bulk insulation (fiberglass, foam, etc.) will only block 10 - 20% of it.

    This is extremely important to remember because up to 90% of all summer heat gain and up to 75% of all winter heat loss is radiant heat.

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      What about the R-Value?

      Some of our products do have an R-Value. For example, Single Bubble Foil has an R-Value of 14.3, Double Bubble Foil is R-14.8. However, No-Tear has no real R-Value.

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      What does R-Value actually mean?

      This is probably one of the most misunderstood values in construction today, and here's why. R-Value only measures an insulation's resistance to CONDUCTIVE heat, which is heat by physical contact. That's important when you are filling up a wall cavity with bulk insulation, and there's contact between the interior drywall and the exterior sheathing.

      But think about your attic. How much conductive heat is up there? Almost none! In the summer, heat is absorbed into the shingles, through the plywood sheathing, where it radiates into the attic. It's then absorbed into the insulation, conducted to the drywall, where it radiates into your house. So what can R-Value do for you here? Not much.

      By installing No-Tear into your attic, you can stop almost all of that radiant heat from getting into your house. So even though No-Tear doesn't have an R-Value, in this case, it works much better than bulk insulation that's already up there. Why? Because No-Tear reflects radiant heat, fiberglass just slows it down.

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      What's the inside scoop on R-Value?

      R-Value is a measurement of how well insulation performs against conductive heat loss. It represents resistance to one square meter of the insulation to a ONE DEGREE TEMPERATURE DIFFERENCE.

      In other words, in a laboratory setting, a piece of insulation is placed between a warm surface of, say, 72 degrees, and a cool surface of 71 degrees. The time it takes for the cool surface to warm up to 72 degrees is the basis for how R-Value is calculated.

      This test does not take the real world setting into account, like humidity, wind, moisture, or the fact that rarely is a house only 1 degree cooler or warmer than the outside temperature.

      So what does all of this mean to you, the home owner? Not a darn thing. Even though we know what it actually means, unfortunately you still have to meet the building codes required for your area.

      However, that does not mean that you can't also use what actually works too, like rFoil and No-Tear. So make sure you meet your building codes, but then add the products that will make your house or building more comfortable, and save you money.

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      What do you mean, "Single Bubble" and "Double Bubble?"

      Single Bubble has a single layer of polyester bubbles between two layers of foil (or a layer of foil and poly). Double Bubble has two layers of bubbles. Double Bubble products are usually sold to the metal building industry; they're rarely used in residential construction.

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      What's the difference between "Foil" and "Poly"?

      Single Bubble Foil is also called Foil/Bubble/Foil, because it's made up of a layer of bubbles sandwiched between two layers of foil; Single Bubble Poly is also called Foil/Bubble/Poly because there is a layer of white poly replacing one of the layers of foil.

      And of course, the same is true for the Double Bubble products.

      We also call Concrete Barrier "Bubble/Foil/Bubble."

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      Should I use Double Bubble?

      It depends. Normally, you can use either Double Bubble Foil or Single Bubble Foil and get the same performance. However, there are a few important exceptions where you want Double Bubble instead of Single Bubble:

      • a crawlspace
      • a garage
      • a wood-frame or steel-frame building
      • if you live in a cold climate (i.e. Minnesota, North Dakota, etc.)
      • when you're only using rFoil and nothing else (i.e. most garages, ag buildings, and crawlspaces)

      If you're not sure, just ask, and we'll give you our recommendation.

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      What's the difference between rFoil and No-Tear?

      It all comes down to this:

      • rFoil has bubbles, No-Tear does not.
      • No-Tear is perforated, rFoil is a vapor barrier (we also have a solid/vapor barrier version of No-Tear).
      • No-Tear is made specifically to use on the attic floor; since rFoil is a vapor barrier, you shouldn't use rFoil on the attic floor.
      • Use rFoil when you need an R-Value, use No-Tear when you don't.

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      Where should I use rFoil or No-Tear?

      There are two specific places to use No-Tear: on the attic floor, and as a housewrap. You should use only No-Tear here because it's perforated to allow moisture to escape.

      You can install rFoil everywhere else: walls, ceilings (under drywall), crawlspaces and basements, water heater, heating ducts, radiant floor heating systems (installed under a wooden floor).

      There is one exception to this: Concrete Barrier. Concrete Barrier should only be used under concrete. Do NOT use regular rFoil.

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      Why should I only use Concrete Barrier under concrete?

      Regular rFoil is made up of a layer of bubbles between two layers of foil. The lime in the concrete will dissolve the foil in just a few years.

      Concrete Barrier is made of a layer of foil between two layers of bubbles. The bubbles protect the foil from the lime, making it a better choice. It's also puncture resistant up to 85 psi, compression resistant up to 140 psi, is a vapor and radon barrier, and is much easier to use than 2" foam board.

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      Do I need an air gap when I install rFoil or No-Tear?

      YES! In order for heat to change from conductive to radiant, there should be at least a 1" air gap on one side of the foil. The best installation will have two air gaps on either side of the foil, but there are times you can't get that.

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      Where should the air gap be?

      The best way to think of this is: 1) The best way, 2) The second best way, and 3) The third best way.

      The best way: There are two air gaps of at least 1" on both sides of the foil.

      The second best way: There is a 1" air gap between the foil and the other building material (drywall, sheathing, roof, etc.). The placement of the gap will depend on where you live. If you live in a warm climate like California or Florida, the air gap should be toward the outside (i.e. between the wall insulation and the foil.

      There is not a major difference in performance between the first and second methods.

      The third best way: There is a 1" air gap on the opposite side of #2. For example, you live in Florida, but you put No-Tear directly against your roof sheathing, rather than underneath your rafters.

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      What if I can't get the best air gap?

      Let's say you can't install rFoil or No-Tear using the first two methods above ("Where should the air gap be?"), so you have to use method #3. A good example of this is putting No-Tear between the roof rafters, directly against the plywood. If you can install it this way without hurting yourself on the roofing nails, here's how it will work.

      rFoil and No-Tear performance is measured with two different numbers: Reflectivity and emittance.

      Reflectivity is how much heat it will block: 97%, or .97.

      Emittance is how much heat is given off: 3%, or .03.

      Now here's the amazing part about rFoil and No-Tear: Even though there is no air space to reflect the heat, the emittance will remain the same. This is because aluminum is a poor emitter of heat, but a great conductor (that's why it's used for cooking pots a lot).

      Think about a clothes iron. It has an aluminum surface. If you touch it, it's extremely hot. But if you hold your hand (your other hand, since you just burned your fingers) a few inches away from the iron, it doesn't feel that warm.

      If you install No-Tear on your roof, the roof will become a big iron, emitting very little heat. The same is true of installing it on the attic floor: in the winter, your attic floor will become a big iron.

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      Should I install No-Tear on the roof or the attic floor?

      That's almost a judgement call on your part. If you live in a hot climate, the roof would be better. If you live in a cold climate, the attic floor would be better. But there are a couple of factors to consider.

      1. If you install No-Tear on the roof, you also need to cover the gable ends (that's the part that looks like a big triangle).

      2. You need more for the roof line than you do the attic floor, because of the slope of the roof.

      3. If you live in a cold climate, installing it on the attic floor will also reduce winter heat loss (see "What if I can't get the best air gap?").

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      Where exactly should I install No-Tear/rFoil on the roof?

      For whatever reason, people want to install as close to the roof as possible. And while this will work (see "What if I can't get the best air gap?" for a great explanation of why), the installation will work better if there is that crucial 1" air gap between the roof and the No-Tear.

      The two best ways to achieve the air gap?

      1. Install No-Tear directly underneath the rafters, running them ACROSS the rafters, instead of with them (up and down). This will save you a lot of time with cutting and stapling.

      2. Install No-Tear between the rafters, but still 1" - 2" away from the roof. This is useful if you are going to finish your attic off later.

      IMPORTANT: If you install No-Tear on your roof, be sure to leave a 3" - 6" gap at the peak and down at the eaves (where the roof and floor meet). This will allow good ventilation behind the No-Tear.

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      How should I install this in my walls?

      Before you start, realize that you're going to have to use bulk insulation in your walls as well. Most people use fiberglass, although we're partial to cellulose ourselves.

      The best way to install this is to have the air gap on the warm side of the house. That is, if you live in a hot weather climate, the air gap should be between the rFoil and the fiberglass. If you live in a cold weather climate, the air gap should be between the rFoil and the drywall.

      Since rFoil is a vapor barrier, you don't want to use another vapor barrier in the wall. Most fiberglass batts come with a kraft paper vapor barrier. After you install the fiberglass, put a few 6" cuts in the paper with your utility knife, then install the rFoil as you normally would.

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      I can't get an air gap in my walls. What can I do?

      First of all, check the thickness of your wall studs. Are you using 2x4s, 2x6s, or 2x8s?

      If you have 2x8s, just use regular 6" R-19 (code requirement in most states), push it far enough back, then install rFoil between the studs (or directly over them) to get the air gap.

      If you have 2x6s or 2x4s, there won't be any room for an air gap with 6" insulation (if you are building an R-19 wall with 2x4s, you'll have a tough time -- fiberglass loses its R-Value when it's compressed).

      So what can you do? It's possible to furr out the wall with furring strips. Depending on you climate, you'll need the air gap on the warm side of the house (see "How should I install this in my walls?").

      Let's assume you are in a cold climate, like Wisconsin or North Dakota. Install your fiberglass as usual. Place the furring strips every 16" perpendicular to the studs. Be sure to place them at the top and bottom of the wall too. Cover the strips with rFoil, tape up the seams, and then install your drywall as usual.

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      Can I install drywall directly over rFoil (and other questions)?
      • Yes you can.
      • No, it won't affect anything if you compress the bubbles.
      • Puncturing the bubbles won't be a problem either.
      • Yes, it's stable enough to support the drywall without causing waves.
      • You're right, it WILL be a little harder to install if you can't feel the studs. So just feel around to find them, measure the distance between them, and mark the lines on the drywall.
      • Yes, we have been asked this question more than a few times.

      It is also possible to install rFoil over studs, but wrap it around the studs so there is a small air gap between the rFoil and the drywall. You can download a pdf version of those instructions here.

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      What's the difference between rFoil and the stuff I see in the big stores?

      Well, for one thing, they don't have a cool website like this.

      But more importantly, rFoil is stronger, more durable, and has a 25 year manufacturer's warranty (the only one on the market). Here's why:

      Other reflective insulation manufacturers use foil that's 2.05 mils thick, polyester film (for the bubbles) that's 7 mils thick, but no EVA film. rFoil uses 2.75 mil foil, 10 mil polyester, and an EVA film (EVA film helps the foil laminate to the bubbles better).

      Because we use better components, we can offer a product that lasts longer and holds up better than anyone else in the industry.

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      How much does rFoil cost?

      Well, we'd love to tell you right here, but we can't. But there's an easy way to find out. Just click this link, fill out the quote request form, and you'll get an answer in 2 - 4 business days.

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      Can I get rFoil cut to a specific length or width?

      Sure you can. If you want pieces that are 23.75” wide and 119 feet long, we can do it. However, there may be an extra charge and a few extra weeks added to your lead time.

      Our most common requests are to have rFoil cut to a specific length. What we always recommend is this: rFoil comes in 125 foot lengths, and it’s very easy to cut with a utility knife or a pair of scissors -- it’s just like cutting plastic bubble wrap (in fact, it IS cutting plastic bubble wrap). Save yourself the extra money and delivery time by cutting it yourself.

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      I've got some extra material. What can I do with it?

      Lots of things. The two most obvious answers are:

      • wrap your water heater
      • wrap your heating/AC ducts

      But you can also:

      • wrap a cooler
      • cut out shoe inserts and stick them in your shoes to keep your feet warm in winter
      • stick shoe inserts in someone else's shoes to make their feet hot in summer
      • wrap it around a small refrigerator
      • wrap it around a large refrigerator
      • wrap a pizza box to keep it warm on the way home
      • insulate a garden shed
      • insulate a dog house
      • put it under a dog blanket or bed
      • put it over a tent
      • put it under a sleeping bag on a cold night
      • put it under someone else's sleeping bag on a warm night
      • wrap frozen fish
      • sit on a piece at a football game or other fall sporting event
      • sit on a piece while ice fishing
      • cut out pieces to wrap cold drink cans or bottles
      • use as java jackets for hot coffee
      • show it to your friends, tell them where you got it, and how to find our website

      Do you have any new ideas? Send us an email and give us your idea.

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      Location: Home » Products » rFoil » FAQ

      WE International, Inc.
      PO Box 97
      Syracuse, Indiana 46567 USA
      Tel: (574) 457-3066
      Fax: (574) 457-5661
      Email: weexport@we-intl.com