The formal kinetics of self-ignition of solid bulk materials theoretically can be derived from just one single adiabatic hot-storage test. The question arises how uncertainties in the measurements can be quantified and how these uncertainties affect the results of the subsequent predictions. Adiabatic and isoperibolic hot-storage basket tests were performed for samples of lignite coal, black coal, cork dust, a polymer dust, and wax-coated silicid acid. In the adiabatic experiments, the starting temperature and the temperature control of the oven were varied systematically to study the uncertainty margin of adiabatic tests. The apparent activation energy and the pre-exponential factor of the lumped reaction were derived from the adiabatic tests including average values and standard deviations and compared to isoperibolic experiments performed according to the European standard EN 15188. It could be shown that with a precise temperature control of the adiabatic oven combined with an automated computation of the maximum rate of temperature rise the uncertainty of the apparent activation energy can be limited to less than 10%.