Foamed concrete technology has led to the production of lighter concretes in the general building and construction industry. By varying the batch composition, it is possible to adjust the bulk density within a wide range (0,5...2,0 g/cm 3 ). By way of introduction, this paper outlines foamed concrete technology, presenting results and findings relevant to this material. Following on from this, possibilities for using this technology for thermal insulation at high temperatures are suggested. The results of tests, including tests with special raw materials, show thatfoamed castables technology can offer interesting solutions for kiln and furnace construction.