Aerogel-filled bricks are great at insulating, but not on the cheap
Why bother adding a layer of insulation to a brick wall, if you can just build that wall using hollow bricks that are stuffed with insulation? That's the thinking behind self-insulating bricks which incorporate materials such as perlite, mineral wool or polystyrene. 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.
The difference was even more pronounced when comparing the aerobricks to plain ol' non-insulting bricks, which conduct heat up to eight times better. According to Empa, this means that in order to match the insulating value of an aerobrick wall that was just 20 cm thick (7.9 in), a wall made from non-insulating bricks would have to be almost 2 meters thick (6.6 ft).
There is a catch, however. The aerogel used in the aerobricks is currently quite expensive – Wernery figures that one square meter of a wall made with them would generate additional costs of around 500 Swiss francs (about US$521). Nonetheless, he hopes that as technology advances and the price of the aerogel falls, the aerobricks will become a practical building material.