Certain materials regularly used in the thermal insulation of buildings are not fireproof. A different problem occurs with fireproof and thermal clothing. Appropriate fire and thermal insulation materials are often non-renewable. Sheep wool is a renewable and fireproof insulator. Because of these properties, I wanted to explore whether wool could be used as a substitute for fire-retardant and renewable material. I compared it to polystyrene insulation foam and found that wool has suitable physical properties for replacement. I also compared sheep wool to regularly used fabrics to determine if it is a satisfactory material for thermal and fireproof clothing. Wool is only partially suitable for building insulation, mainly due to its durability and fire-retardant properties. The polystyrene used to insulate the walls is extremely flammable and wool is an exceptional replacement. Unlike polystyrene, however, the mineral wool used to insulate attics is not as flammable and it does not make sense to replace the material. Sheep wool safety clothing is much more fireproof and resistant to heat and fire than other regularly used materials.