About Reflective Technology

The Scottish chemist and physicist Sir James Dewar invented the Thermos flask, also known as the Dewar flask or vacuum flask, in the 1890's for the purpose of storing liquid gases at very low temperatures. The basic function of the vacuum flask is to thermally insulate the contents and prevent heat flowing either in or out.

In our illustration, radiation is reduced to a minimum by silvering the glass, generally on the two internal faces, so that the radiant heat waves are reflected. Different types of insulation products reduce the heat transferred by conduction, convection and radiation to varying degrees. As a result, each provides different thermal performance and corresponding "R" values. The primary function of reflective insulation is to reduce radiant heat transfer across open spaces. The low emittance metal (usually aluminum) surface of reflective insulation blocks up to 97% of the radiation and therefore, a significant part of the heat transfer.

Reflective Insulation vs. Mass Insulation
A foam cup "insulates" a cup of coffee as mass insulation does and attains an actual R-value. The reflective surface of a Thermos jug lining keeps liquid hot or cold. If, for example, you take hot coffee the heat within a Thermos is reflected back inside while the cold outside is reflected away. Like the Thermos jug in the illustration, Reflectix® Insulation reflects and separates "heat" from -60 degrees to a +180 degrees without an R-value. Would you rather drink coffee from a Thermos jug or a foam cup hours later?

If you would like to learn more about Reflective Insulation and Radiant Barrier, download the RIMA Handbook (1MB PDF).