Electron spin resonance was used to characterize concentrations of thermal equilibrium defects from room temperature of 280 °C in a 60‐micron‐thick hydrogenated amorphous silicon (a‐Si:H) film. I found a defect formation energy of 0.35 eV in material with 1×1015cm−3spins at 190 °C; an assumed two‐level configuration coordinate diagram would then have a ‘‘source’’ density of 1019cm−3. Annealing of defects quenched in from 250 °C yields an activation energy of 2.1 eV. When annealings of defects quenched in from high and low temperature are comparedthe defects introduced at the higher temperature always anneal faster; The metastable states with higher formation energies have smaller annealing activation energies. Additionally, the time constant for generation of defects at 205 °C is 10 times longer than the corresponding annealing time constant, consistent with the very high formation barrier expected for this two‐level system. The stretch parameter for defect generation is much closer to unity than for defect annealing. Easy‐to‐anneal, light‐induced defects can be described as a very high‐temperature distribution similar to that which might be quenched in as a result of kT&bartil;0.5 eV.