Double foil bubble insulation is a flexible reflective insulation family built around one or more layers of trapped air. The “double foil” part usually refers to foil facings on both sides; the “bubble” part refers to the polyethylene bubble core. Buyers often compare single-bubble and double-bubble constructions, then choose a facing: aluminum foil, metallized film, or a woven-backed laminate. This article describes construction differences in generic terms and lists the checks that matter on a spec sheet. It does not assign R-values to bubble/foil products, because radiant products are not specified the same way as mass insulation.
Single bubble vs double bubble in double foil bubble insulation
Single-bubble material typically has one bubble layer between two facings. The bubble layer creates a thin, discontinuous air space. The facings provide the reflective surfaces. In a double foil bubble insulation product, both outer surfaces are foil or foil-laminate facings. Single-bubble rolls are generally thinner and more flexible. They conform to irregular surfaces, wrap around corners, and are easier to cut with hand tools. The trade-off is less thickness and fewer trapped-air gaps than a double-bubble core.
Double-bubble material typically has two bubble layers. The layers may be bonded directly or separated by an additional film or membrane, depending on construction. The result is a thicker profile with more trapped air spaces. Double-bubble rolls are often stiffer and heavier than single-bubble rolls. That can help where the material must span small gaps or stay flat across a frame, but it can make tight wrapping more difficult. Neither construction should be selected by bubble count alone. Edge sealing, facing type, installation compression, and reflective-surface direction all affect service performance.
Reflective facings reduce radiant heat transfer. They do not stop conductive or convective heat flow. The bubble core reduces conduction and convection by limiting air movement. In a roof or wall assembly, the reflective surface must face an open air space to be effective. If the foil is sandwiched tightly between materials, the radiant benefit is reduced. For installation details, see radiant barrier installation. For a broader look at foil products, see foil insulation uses.
Foil facing options for double foil bubble insulation
Facing choice is as important as bubble count. The two common facing families are aluminum foil and metallized film. Aluminum foil facing uses a thin aluminum sheet laminated to the bubble core. It is opaque and reflective. Metallized film facing uses a polymer film with a deposited metal layer. It is also reflective, but the reflective layer is much thinner than a foil sheet. The two facings can look similar in a photograph, so the spec sheet should identify the facing material rather than only the color.
Woven backing is another option. A woven scrim can be laminated behind or between foil layers to add tear resistance and dimensional stability. This is common in products intended for walls, roofs, or wrap applications where the material may be pulled over purlins or framing. Qiyao lists examples such as “Aluminum Foil Woven Fabric Build Sarking Radiant Barrier Wall Roof Wrap” and “Reflective Woven Foil Blankets Thermal Heat Reflective Radiant Barrier.” A foil laminate example is “Reflective Pet Al PE Laminated Foil Pet+Alu+PE,” which shows how PET, aluminum, and PE layers can be combined in one facing. More foil-facing options are described in the foil product section.
When comparing facings, ask whether the foil is perforated or non-perforated. Perforation changes how the facing interacts with moisture vapor and can affect whether the product acts as a vapor retarder. Ask about the reflective surface: is it exposed, coated, or laminated under a protective film? Ask whether the facing is intended for indoor or outdoor exposure. The answers should come from the manufacturer’s data sheet, not a generic description. For reflective foil products, thermal conductivity is not the main published value; the products work by reflecting radiant heat.
Where bubble insulation is used
Bubble insulation appears in several B2B categories. In metal buildings, single- or double-bubble foil products are used as roof and wall wrap, sarking, and radiant barriers behind cladding. The reflective facing is oriented toward the air space. The material can also be used over purlins or as a liner in framed assemblies. Installation method matters: fasteners, seams, and compression can create thermal bridges or reduce the reflective air space.
In HVAC work, bubble insulation is used as duct wrap. The foil facing reflects radiant heat, while the bubble core limits air movement around the duct. The wrap is typically cut to width and secured with suitable tape or mechanical fasteners. Because ducts can be irregular, single-bubble material is sometimes easier to conform than double-bubble material. Double-bubble material may be preferred where a thicker, less compressible wrap is needed.
In packaging and cold-chain transport, reflective bubble liners are used in boxes, bags, and container covers. Qiyao product names include “20FT Reusable Aluminum Foil Thermal Insulated Bag” and “40FT Aluminum Foil Thermal Insulated Bag Custom Container Liner.” Bubble insulation also appears in pallet covers and thermal pallet shippers, such as the “140 Hours Thermal Large Size 1000L Pallet Shipper for Cold Chain Transport” and “Cold Chain Pallet Shipper 168 Hour Shipment.” These products pair reflective facings with insulated shipping formats; confirm the construction per product page.
Window applications are another use. Double foil bubble insulation can be cut to size for temporary or seasonal window panels. It is often installed with the reflective side facing the interior or exterior air space, depending on the goal. The material is not transparent, so it blocks light. It is also not a substitute for a sealed glazing system. For more application notes, see foil insulation uses.
What to check on a spec sheet
A useful bubble insulation spec sheet should list the facing material, not just “foil.” It should state whether the facing is aluminum foil or metallized film, and whether a woven scrim or laminate is present. It should state the bubble layer count: single or double. It should give the nominal thickness, width, and roll length. If the product is sold by the roll, confirm whether the stated width is the total width or the usable width after overlap.
Check perforation. A perforated facing allows vapor movement through the facing; a non-perforated facing may be selected where a lower-permeance surface is required. Check the reflective surface orientation and any installation instructions. Check temperature limits if the product will be used near hot equipment. Industry-typical lead times are 15–25 days for standard orders and 25–35 days for custom sizes; samples are available; confirm at time of order. Certificates are available upon request.
Hangzhou Qiyao New Material Co., Ltd., an insulation materials manufacturer established 2017 in Hangzhou, Zhejiang, China, lists reflective foil insulation (from $0.15) and foil laminated barrier film among its on-sale lines on Made-in-China. OEM/ODM and samples are available. For pricing and custom sizes, contact Judy at +86 0571 8606 2609 or [email protected].