An aeroderivative gas turbine provided with a casing, a compressor including a rotor mounted on a generator shaft supported for rotation in the casing, a high pressure turbine arranged in the casing and with a rotor mounted on the generator shaft for co-rotation with the compressor rotor, a combustor, a power turbine arranged in the casing and including a rotor mounted on a turbine shaft to drive a load, wherein a thermal insulation coating is present to reduce heat dispersion through the casing.