Reflective insulation is sold under many trade names, but almost every product is one of three constructions: aluminium foil on a bubble core, on a foam core, or on a woven scrim with no core at all. Each solves a different problem. Picking the wrong one is the most common mistake we see in inquiries.
The physics in one paragraph
Heat crosses an air gap mostly as radiation. A clean aluminium surface reflects most of it, which is why all three constructions work as radiant barriers when the foil faces an air space. The core, if there is one, adds a little resistance to conduction and gives the sheet body. The core does not make the foil reflect better; it makes the product easier to handle and slightly better in assemblies without a proper air gap.
Foil-bubble
Aluminium foil or metallised film bonded to one or two layers of polyethylene bubble. Light, cheap, easy to cut with a knife and staple to timber. The standard choice for under-roof radiant barriers, wall wraps behind cladding, pallet covers and insulated mailers. Its weakness is temperature: the bubble is polyethylene and softens well below the temperature of a hot pipe or an engine cover. Keep it in buildings and packaging.
Foil-foam
Foil bonded to closed-cell polyethylene foam. Denser and quieter than bubble, cushions as well as insulates, and gives a flatter, more finished surface. The usual choice for cooler-bag and delivery-box liners, equipment wraps that must not rattle, and floor underlays. Same temperature limit as bubble, for the same reason.
Foil-scrim
Foil laminated to a woven scrim, sometimes with a kraft or film backing, and no core. Thin, strong and the only one of the three that tolerates real heat, because there is no polyethylene inside. Used for duct wrap, pipe and tank wraps, industrial thermal blankets and any radiant barrier that will be stretched or stapled under tension.
Questions to answer before you specify
- Will the foil face an air gap? If not, none of these will perform as a radiant barrier and you need conventional insulation.
- What temperature will the material see? Above the comfort range of polyethylene, foil-scrim is the only option.
- One foil face or two? Two faces reflect in both directions but cost more and are unnecessary if one side is against a solid surface.
- Does it need to breathe? Perforated versions are available for wall assemblies that must let vapour out.
- Is there a fire rating to meet? Building applications often require an EN 13501-1 classification; tell us the class and we quote a fire-rated grade with its report.
We laminate all three constructions and slit them to width. Send us the application and we will recommend one and provide the test data for it.