Now, scientists from Swiss research group Empa have created what they claim is the best-insulating brick yet, using a type of aerogel.
Aerogels are manufactured materials derived from a gel in which the liquid component of the gel has been replaced with a gas. Along with being extremely lightweight, they have very high thermal insulation properties, which has led to their use in products such as jackets.
In the Empa study, lead scientist Jannis Wernery and his team developed a paste composed of aerogel particles, which can easily be stuffed into regular hollow clay bricks.
When compared to these so-called "aerobricks," perlite-filled bricks of the same structure and thickness insulated by about a third less. This means that in order to offer the same insulation value as an aerobrick wall, a wall made from the perlite-filled bricks would have to be about 35 percent thicker.