I put 6 propane gas blowers in an apartment, the kind that is used at construction sites. Let that run with thermostats and cameras for a few hours. Bedbug free. Have since done it at 2 other apartments after months of infestations, immediately fixed.
Source: personal experience, after trying lots of other methods.
https://www.orkin.com/pests/bed-bugs/does-heating-or-freezin...